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Sample records for planetary atmospheres ii

  1. Exact results in modeling planetary atmospheres-II. Semi-gray atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Rutily, B. [Universite de Lyon, F-69003 Lyon (France); Universite Lyon 1, Observatoire de Lyon, 9 avenue Charles Andre, F-69230 Saint-Genis-Laval (France); CNRS, UMR 5574, Centre de Recherche Astrophysique de Lyon (France); Ecole Normale Superieure de Lyon, F-69007 Lyon (France); Chevallier, L. [Observatoire de Paris-Meudon, Laboratoire LUTH, 5 Place Jules Janssen, 92195 Meudon cedex (France); Pelkowski, J. [Institut fuer Atmosphaere und Umwelt, J.W. Goethe Universitaet Frankfurt, Campus Riedberg, Altenhaferallee 1, D-60438 Frankfurt a.M. (Germany)], E-mail: Pelkowski@meteor.uni-frankfurt.de; Bergeat, J. [Universite de Lyon, F-69003 Lyon (France); Universite Lyon 1, Observatoire de Lyon, 9 avenue Charles Andre, F-69230 Saint-Genis-Laval (France); CNRS, UMR 5574, Centre de Recherche Astrophysique de Lyon (France); Ecole Normale Superieure de Lyon, F-69007 Lyon (France)

    2008-01-15

    We solve the radiative transfer equation for a semi-gray planetary atmosphere in radiative equilibrium, in an attempt to define an entirely analytical non-gray model atmosphere of finite optical thickness. The salient feature of the model is that the incident solar radiation is partitioned between two adjacent spectral domains-the 'visible' and the 'infrared'-in each of which the atmosphere's (effective) opacity is assumed to be independent of frequency (the semi-gray assumption). We envisage a plane-parallel atmosphere illuminated by a beam of parallel radiation and bounded below by a partially reflecting and emitting ground. The former emits infrared radiation, induced by the absorption of radiation both visible and infrared, deriving from the external irradiation as well as from the emission of the planet's surface layer. For an atmosphere with given single-scattering albedos and optical thicknesses in both the visible and infrared domains, we compute the temperature at every depth of the atmosphere, as well as the ground's temperature.

  2. Planetary Atmospheric Electricity

    CERN Document Server

    Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M

    2008-01-01

    This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...

  3. Composition of early planetary atmospheres - II. Coupled Dust and chemical evolution in protoplanetary discs

    Science.gov (United States)

    Cridland, A. J.; Pudritz, Ralph E.; Birnstiel, Tilman; Cleeves, L. Ilsedore; Bergin, Edwin A.

    2017-08-01

    We present the next step in a series of papers devoted to connecting the composition of the atmospheres of forming planets with the chemistry of their natal evolving protoplanetary discs. The model presented here computes the coupled chemical and dust evolution of the disc and the formation of three planets per disc model. Our three canonical planet traps produce a Jupiter near 1 AU, a Hot Jupiter and a Super-Earth. We study the dependence of the final orbital radius, mass, and atmospheric chemistry of planets forming in disc models with initial disc masses that vary by 0.02 M⊙ above and below our fiducial model (M_{disc,0} = 0.1 M_{⊙}). We compute C/O and C/N for the atmospheres formed in our three models and find that C/Oplanet ˜ C/O_{disc}, which does not vary strongly between different planets formed in our model. The nitrogen content of atmospheres can vary in planets that grow in different disc models. These differences are related to the formation history of the planet, the time and location that the planet accretes its atmosphere, and are encoded in the bulk abundance of NH3. These results suggest that future observations of atmospheric NH3 and an estimation of the planetary C/O and C/N can inform the formation history of particular planetary systems.

  4. Lightning detection in planetary atmospheres

    CERN Document Server

    Aplin, Karen L

    2016-01-01

    Lightning in planetary atmospheres is now a well-established concept. Here we discuss the available detection techniques for, and observations of, planetary lightning by spacecraft, planetary landers and, increasingly, sophisticated terrestrial radio telescopes. Future space missions carrying lightning-related instrumentation are also summarised, specifically the European ExoMars mission and Japanese Akatsuki mission to Venus, which could both yield lightning observations in 2016.

  5. Multiple scattering of polarized light in planetary atmospheres. II - Sunlight reflected by terrestrial water clouds.

    Science.gov (United States)

    Hansen, J. E.

    1971-01-01

    The intensity and polarization of sunlight reflected by terrestrial water clouds are computed with the doubling method. The calculations illustrate that this method can be effectively used in problems involving strongly anisotropic phase matrices. The method can, therefore, be used to derive information about planetary clouds, including those of the earth, from polarimetric observations. The results of the computations indicate that the polarization is more sensitive than the intensity to cloud microstructure, such as particle size and shape.

  6. Planetary atmosphere processes

    Energy Technology Data Exchange (ETDEWEB)

    Sidorenkov, N.S.

    1991-01-01

    The papers presented in this volume focus on various atmospheric processes, including zonal circulation of the atmosphere, the quasi-biennial cycle, blocking processes, monsoon circulation, and the response of the atmosphere to solar corpuscular fluxes. Other topics discussed include climatic characteristics of atmospheric circulation in the Northern and Southern Hemispheres, seasonal changes of the geopotential in the tropical stratosphere, and characteristics of the Southern Oscillation-El Nino phenomenon.

  7. Clouds in Planetary Atmospheres

    Science.gov (United States)

    West, R.; Murdin, P.

    2000-11-01

    What are clouds? The answer to that question is both obvious and subtle. In the terrestrial atmosphere clouds are familiar as vast collections of small water drops or ice crystals suspended in the air. In the atmospheres of Venus, Mars, Jupiter, Saturn, Saturn's moon Titan, Uranus, Neptune, and possibly Pluto, they are composed of several other substances including sulfuric acid, ammonia, hydroge...

  8. Evolution of the solar activity over time and effects on planetary atmospheres. II. kappa^1 Ceti, an analog of the Sun when life arose on Earth

    CERN Document Server

    Ribas, I; Ferreira, L D; Hebrard, E; Selsis, F; Catalan, S; Garces, A; Nascimento, J D do; de Medeiros, J R

    2010-01-01

    The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigation of the atmospheric parameters, state of evolution and high-energy fluxes of the nearby star kap^1 Cet, previously thought to have properties resembling those of the early Sun. Atmospheric parameters were derived from the excitation/ionization equilibrium of Fe I and Fe II, profile fitting of Halpha and the spectral energy distribution. The UV irradiance was derived from FUSE and HST data, and the absolute chromospheric flux from the Halpha line core. From careful spectral analysis and the comparison of different methods we propose for kap^1 Cet the following atmospheric parameters: Teff = 5665+/-30 K (Halpha profil...

  9. Spectroscopic detection and characterisation of planetary atmospheres

    Directory of Open Access Journals (Sweden)

    Collier Cameron A.

    2011-07-01

    Full Text Available Space based broadband infrared observations of close orbiting extrasolar giant planets at transit and secondary eclipse have proved a successful means of determining atmospheric spectral energy distributions and molecular composition. Here, a ground-based spectroscopic technique to detect and characterise planetary atmospheres is presented. Since the planet need not be transiting, this method enables a greater sample of systems to be studied. By modelling the planetary signature as a function of phase, high resolution spectroscopy has the potential to recover the signature of molecules in planetary atmospheres.

  10. Submillimeter Planetary Atmospheric Chemistry Exploration Sounder

    Science.gov (United States)

    Schlecht, Erich T.; Allen, Mark A.; Gill, John J.; Choonsup, Lee; Lin, Robert H.; Sin, Seth; Mehdi, Imran; Siegel, Peter H.; Maestrini, Alain

    2013-01-01

    Planetary Atmospheric Chemistry Exploration Sounder (SPACES), a high-sensitivity laboratory breadboard for a spectrometer targeted at orbital planetary atmospheric analysis. The frequency range is 520 to 590 GHz, with a target noise temperature sensitivity of 2,500 K for detecting water, sulfur compounds, carbon compounds, and other atmospheric constituents. SPACES is a prototype for a powerful tool for the exploration of the chemistry and dynamics of any planetary atmosphere. It is fundamentally a single-pixel receiver for spectral signals emitted by the relevant constituents, intended to be fed by a fixed or movable telescope/antenna. Its front-end sensor translates the received signal down to the 100-MHz range where it can be digitized and the data transferred to a spectrum analyzer for processing, spectrum generation, and accumulation. The individual microwave and submillimeter wave components (mixers, LO high-powered amplifiers, and multipliers) of SPACES were developed in cooperation with other programs, although with this type of instrument in mind. Compared to previous planetary and Earth science instruments, its broad bandwidth (approx. =.13%) and rapid tunability (approx. =.10 ms) are new developments only made possible recently by the advancement in submillimeter circuit design and processing at JPL.

  11. Atmospheric escape, redox evolution, and planetary habitability

    Science.gov (United States)

    Catling, D. C.; Zahnle, K. J.

    2011-12-01

    Through the greenhouse effect, the presence and composition of an atmosphere is critical for defining a (conventional) circumstellar habitable zone in terms of planetary surface temperatures suitable for liquid water. Lack of knowledge of planetary atmospheres is likely to frustrate attempts to say with any certainty whether detected terrestrial-sized exoplanets may or may not be habitable. Perhaps an underappreciated role in such considerations is the evolutionary effect of atmospheric escape for determining atmospheric composition or whether an atmosphere exists in the first place. Whether atmospheres exist at all on planets is demonstrably connected to the effect of integrated atmospheric escape. When we observe our own Solar System and transiting exoplanets, the existence of an atmosphere is clearly delineated by a relative vulnerability to thermal escape and impact erosion. The prevalence of thermal escape as a key evolutionary determinant for the presence of planetary atmosphere is shown by a relationship between the relative solar (or stellar) heating and the escape velocity. Those bodies with too much stellar heating and too smaller escape velocity end up devoid of atmospheres. Impact erosion is evident in the relationship between impact velocity and escape velocity. Escape due to impacts is particularly important for understanding the large differences in the atmospheres of giant planet moons, such as Ganymede versus Titan. It is also significant for Mars-sized planets. The oxidation state of atmospheres is important for some theories of the origin of life (where an early reducing atmosphere is helpful for organic synthesis) and the evolution of advanced life (where free molecular oxygen is the best source of high energy metabolism). Surfaces on some relatively small planets and moons are observed to have evolved to an oxidized state, which theory and observation can explain through atmospheric escape. There are several examples in the Solar System where a

  12. Atmospheric Retrieval for Direct Imaging Spectroscopy of Gas Giants In Reflected Light II: Orbital Phase and Planetary Radius

    CERN Document Server

    Nayak, Michael; Marley, Mark; Fortney, Jonathan; Robinson, Tyler; Lewis, Nikole

    2016-01-01

    Future space-based telescopes, such as the Wide-Field Infrared Survey Telescope (WFIRST), will observe the reflected-light spectra of directly imaged extrasolar planets. Interpretation of such data presents a number of novel challenges, including accounting for unknown planet radius and uncertain stellar illumination phase angle. Here we report on our continued development of Markov Chain Monte Carlo retrieval methods for addressing these issues in the interpretation of such data. Specifically we explore how the unknown planet radius and potentially poorly known observer-planet-star phase angle impacts retrievals of parameters of interest such as atmospheric methane abundance, cloud properties and surface gravity. As expected, the uncertainty in retrieved values is a strong function of signal-to-noise ratio (SNR) of the observed spectra, particularly for low metallicity atmospheres, which lack deep absorption signatures. Meaningful results may only be possible above certain SNR thresholds; for cases across a ...

  13. Atmospheric Retrieval for Direct Imaging Spectroscopy of Gas Giants in Reflected Light. II. Orbital Phase and Planetary Radius

    Science.gov (United States)

    Nayak, Michael; Lupu, Roxana; Marley, Mark S.; Fortney, Jonathan J.; Robinson, Tyler; Lewis, Nikole

    2017-03-01

    Future space-based telescopes, such as the Wide-Field Infrared Survey Telescope (WFIRST), will observe the reflected light spectra of directly imaged extrasolar planets. Interpretation of such data presents a number of novel challenges, including accounting for unknown planet radius and uncertain stellar illumination phase angle. Here, we report on our continued development of Markov Chain Monte Carlo retrieval methods for addressing these issues in the interpretation of such data. Specifically, we explore how the unknown planet radius and potentially poorly known observer-planet-star phase angle impacts retrievals of parameters of interest such as atmospheric methane abundance, cloud properties, and surface gravity. As expected, the uncertainty in retrieved values is a strong function of the signal-to-noise ratio (S/N) of the observed spectra, particularly for low metallicity atmospheres, which lack deep absorption signatures. Meaningful results may only be possible above certain S/N thresholds; for cases across a metallicity range of 1–50 times solar, we find that only an S/N of 20 systematically reproduces a value close to the correct methane abundance at all phase angles. However, even in cases where the phase angle is poorly known we find that the planet radius can be constrained to within a factor of two. We find that uncertainty in planet radius decreases at phase angles past quadrature, as the highly forward-scattering nature of the atmosphere at these geometries limits the possible volume of phase space that relevant parameters can occupy. Finally, we present an estimation of possible improvement that can result from combining retrievals against observations at multiple phase angles.

  14. Chemistry of Planetary Atmospheres: Insights and Prospects

    Science.gov (United States)

    Yung, Yuk

    2015-11-01

    Using observations from the Mariners, Pioneers, Vikings, Voyagers, Pioneer Venus, Galileo, Venus Express, Curiosity, Cassini, New Horizons, and numerous observatories both in orbit of Earth and on the ground, I will give a survey of the major chemical processes that control the composition of planetary atmospheres. For the first time since the beginning of the space age, we understand the chemistry of planetary atmospheres ranging from the primitive atmospheres of the giant planets to the highly evolved atmospheres of terrestrial planets and small bodies. Our understanding can be distilled into three important ideas: (1) The stability of planetary atmospheres against escape of their constituents to space, (2) the role of equilibrium chemistry in determining the partitioning of chemical species, and (3) the role of disequilibrium chemistry, which produces drastic departures from equilibrium chemistry. To these three ideas we must also add a fourth: the role of biochemistry at Earth's surface, which makes its atmospheric chemistry unique in the cosmochemical environment. Only in the Earth's atmosphere do strong reducing and oxidizing species coexist to such a degree. For example, nitrogen species in the Earth's atmosphere span eight oxidation states from ammonia to nitric acid. Much of the Earth's atmospheric chemistry consists of reactions initiated by the degradation of biologically produced molecules. Life uses solar energy to drive chemical reactions that would otherwise not occur; it represents a kind of photochemistry that is special to Earth, at least within the Solar System. It remains to be seen how many worlds like Earth there are beyond the Solar System, especially as we are now exploring the exoplanets using Kepler, TESS, HST, Spitzer, soon to be launched missions such as JWST and WFIRST, and ground-based telescopes. The atmospheres of the Solar System provide a benchmark for studying exoplanets, which in turn serve to test and extend our current

  15. Diurnal Forcing of Planetary Atmospheres

    Science.gov (United States)

    Houben, Howard C.

    1997-01-01

    Much progress has been made on calculations of the Martian seasonal water cycle using the Mars Climate Model developed for this purpose. Two papers, documenting the model and the water transport results obtained with it have been published in the Journal of Geophysical Research - Planets. An additional paper describing results related to the evolution of the seasonal water cycle as a result of orbital changes was published in Advances in Space Research. Since that time, further studies have concentrated on the consequences of the soil adsorption required to match the observed water cycle and its relation to the stability of ground ice and other potential water reservoirs. Earth-related studies have concentrated on incorporating an efficient and realistic microphysical model into the Ames Stratospheric General Circulation Model used to simulate the spread of the ML Pinatubo and other volcanic clouds in the stratosphere. In addition, visualizations of the simulations are being incorporated into a video describing the UARS mission. A paper describing the new stratospheric aerosol microphysics package (and its consequences for volcanic cloud evolution) will be submitted in the near future. The paper will discuss the relative importance of condensation and coagulation to early particle growth and the separation of the cloud by sedimentation of the larger particles. A more general paper which highlights the observation that particle number densities did not increase dramatically after the ML Pinatubo eruption is planned. Simulations of atmospheric transport will be extended to include studies of terrestrial tropospheric tracers using the Fifth-Generation Penn State/NCAR Mesoscale Model.

  16. Exact results in modeling planetary atmospheres-I. Gray atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Chevallier, L. [Observatoire de Paris-Meudon, Laboratoire LUTH, 5 Place Jules Janssen, 92195 Meudon cedex (France)]. E-mail: loic.chevallier@obspm.fr; Pelkowski, J. [Institut fuer Meteorologie und Geophysik, J.W. Goethe Universitaet Frankfurt, Robert Mayer Strasse 1, D-60325 Frankfurt (Germany); Rutily, B. [Universite de Lyon, Lyon, F-69000 (France) and Universite Lyon 1, Villeurbanne, F-69622 (France) and Centre de Recherche Astronomique de Lyon, Observatoire de Lyon, 9 avenue Charles Andre, Saint-Genis Laval cedex, F-69561 (France) and CNRS, UMR 5574; Ecole Normale Superieure de Lyon, Lyon (France)

    2007-04-15

    An exact model is proposed for a gray, isotropically scattering planetary atmosphere in radiative equilibrium. The slab is illuminated on one side by a collimated beam and is bounded on the other side by an emitting and partially reflecting ground. We provide expressions for the incident and reflected fluxes on both boundary surfaces, as well as the temperature of the ground and the temperature distribution in the atmosphere, assuming the latter to be in local thermodynamic equilibrium. Tables and curves of the temperature distribution are included for various values of the optical thickness. Finally, semi-infinite atmospheres illuminated from the outside or by sources at infinity is dealt with.

  17. Carbon Monoxide Affecting Planetary Atmospheric Chemistry

    Science.gov (United States)

    He, Chao; Horst, Sarah

    2016-10-01

    Atmospheric hazes are present in a range of solar system and extrasolar planetary atmospheres, and organic hazes, such as that in Titan's atmosphere, could be a source of prebiotic molecules.1 However, the chemistry occurring in planetary atmospheres and the resulting chemical structures are still not clear. Numerous experimental simulations2 have been carried out in the laboratory to understand the chemistry in N2/CH4 atmospheres, but very few simulations4 have included CO in their initial gas mixtures, which is an important component in many N2/CH4 atmospheres including Titan, Triton, and Pluto.3 Here we have conducted a series of atmosphere simulation experiments using AC glow discharge (cold plasma) as energy source to irradiate reactions in gas mixtures of CO, CH4, and N2 with a range of CO mixing ratios (from 0, 0.05%, 0.2%, 0.5%, 1%, 2.5%, to 5%) at low temperature (~100 K). Gas phase products are monitored during the reaction by quadrupole mass spectrometer (MS), and solid phase products are analyzed by solution-state nuclear magnetic resonance spectroscopy (NMR). MS results show that with the increase of CO in the initial gases, the production of nitrogenous organic molecules increases while the production of hydrogen molecules decreases in the gas phase. NMR measurements of the solid phase products show that with the increase of CO, hydrogen atoms bonded to nitrogen or oxygen in unsaturated structures increase while those bonded to saturated carbon decrease, which means more unsaturated species and less saturated species formed with the addition of CO. MS and NMR results demonstrate that the inclusion of CO affects the compositions of both gas and solid phase products, indicating that CO has an important impact on the chemistry occurring in our experiments and probably in planetary atmospheres.1. Hörst, S. M., et al. 2012, AsBio, 12, 8092. Cable, M. L., et al. 2012, Chem. Rev., 112, 18823. Lutz, B. L., et al. 1983, Sci, 220, 1374; Greaves, J. S., et al

  18. The GISS global climate-middle atmosphere model. II - Model variability due to interactions between planetary waves, the mean circulation and gravity wave drag

    Science.gov (United States)

    Rind, D.; Suozzo, R.; Balachandran, N. K.

    1988-01-01

    The variability which arises in the GISS Global Climate-Middle Atmosphere Model on two time scales is reviewed: interannual standard deviations, derived from the five-year control run, and intraseasonal variability as exemplified by statospheric warnings. The model's extratropical variability for both mean fields and eddy statistics appears reasonable when compared with observations, while the tropical wind variability near the stratopause may be excessive possibly, due to inertial oscillations. Both wave 1 and wave 2 warmings develop, with connections to tropospheric forcing. Variability on both time scales results from a complex set of interactions among planetary waves, the mean circulation, and gravity wave drag. Specific examples of these interactions are presented, which imply that variability in gravity wave forcing and drag may be an important component of the variability of the middle atmosphere.

  19. Planetary Atmospheres and Evolution of Complex Life

    Science.gov (United States)

    Catling, D.

    2014-04-01

    Let us define "complex life" as actively mobile organisms exceeding tens of centimeter size scale with specialized, differentiated anatomy comparable to advanced metazoans. Such organisms on any planet will need considerable energy for growth and metabolism, and an atmosphere is likely to play a key role. The history of life on Earth suggests that there were at least two major hurdles to overcome before complex life developed. The first was biological. Large, three-dimensional multicellular animals and plants are made only of eukaryotic cells, which are the only type that can develop into a large, diverse range of cell types unlike the cells of microbes. Exactly how eukaryotes allow 3D multicellularity and how they originated are matters of debate. But the internal structure and bigger and more modular genomes of eukaryotes are important factors. The second obstacle for complex life was having sufficient free, diatomic oxygen (O2). Aerobic metabolism provides about an order of magnitude more energy for a given intake of food than anaerobic metabolism, so anaerobes don't grow multicellular beyond filaments because of prohibitive growth efficiencies. A precursor to a 2.4 Ga rise of oxygen was the evolution of water-splitting, oxygen-producing photosynthesis. But although the atmosphere became oxidizing at 2.4 Ga, sufficient atmospheric O2 did not occur until about 0.6 Ga. Earth-system factors were involved including planetary outgassing (as affected by size and composition), hydrogen escape, and processing of organic carbon. An atmosphere rich in O2 provides the largest feasible energy source per electron transfer in the Periodic Table, which suggests that O2 would be important for complex life on exoplanets. But plentiful O2 is unusual in a planetary atmosphere because O2 is easily consumed in chemical reactions with reducing gases or surface materials. Even with aerobic metabolism, the partial pressure of O2 (pO2) must exceed ~10^3 Pa to allow organisms that rely

  20. Molecular Dications in Planetary Atmospheric Escape

    Directory of Open Access Journals (Sweden)

    Stefano Falcinelli

    2016-08-01

    Full Text Available Fundamental properties of multiply charged molecular ions, such as energetics, structure, stability, lifetime and fragmentation dynamics, are relevant to understand and model the behavior of gaseous plasmas as well as ionosphere and astrophysical environments. Experimental determinations of the Kinetic Energy Released (KER for ions originating from dissociations reactions, induced by Coulomb explosion of doubly charged molecular ions (molecular dications produced by double photoionization of CO2, N2O and C2H2 molecules of interest in planetary atmospheres, are reported. The KER measurement as a function of the ultraviolet (UV photon energy in the range of 28–65 eV was extracted from the electron-ion-ion coincidence spectra obtained by using tunable synchrotron radiation coupled with ion imaging techniques at the ELETTRA Synchrotron Light Laboratory Trieste, Italy. These experiments, coupled with a computational analysis based on a Monte Carlo trajectory simulation, allow assessing the probability of escape for simple ionic species in the upper atmosphere of Mars, Venus and Titan. The measured KER in the case of H+, C+, CH+, CH2+, N+, O+, CO+, N2+ and NO+ fragment ions range between 1.0 and 5.5 eV, being large enough to allow these ionic species to participate in the atmospheric escape from such planets into space. In the case of Mars, we suggest a possible explanation for the observed behavior of the O+ and CO22+ ion density profiles.

  1. Meteoric Material: An Important Component of Planetary Atmospheres

    Science.gov (United States)

    Grebowsky, Joseph M.; Moses, Julianne I.; Pesnell, W. Dean; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Interplanetary dust particles (IDPs) interact with all planetary atmospheres and leave their imprint as perturbations of the background atmospheric chemistry and structure. They lead to layers of metal ions that can become the dominant positively charged species in lower ionospheric regions. Theoretical models and radio occultation measurements provide compelling evidence that such layers exist in all planetary atmospheres. In addition IDP ablation products can affect neutral atmospheric chemistry, particularly at the outer planets where the IDPs supply oxygen compounds like water and carbon dioxide to the upper atmospheres. Aerosol or smoke particles from incomplete ablation or recondensation of ablated IDP vapors may also have a significant impact on atmospheric properties.

  2. Alien skies planetary atmospheres from earth to exoplanets

    CERN Document Server

    Pont, Frédéric J

    2014-01-01

    Planetary atmospheres are complex and evolving entities, as mankind is rapidly coming to realise whilst attempting to understand, forecast and mitigate human-induced climate change. In the Solar System, our neighbours Venus and Mars provide striking examples of two endpoints of planetary evolution, runaway greenhouse and loss of atmosphere to space. The variety of extra-solar planets brings a wider angle to the issue: from scorching "hot jupiters'' to ocean worlds, exo-atmospheres explore many configurations unknown in the Solar System, such as iron clouds, silicate rains, extreme plate tectonics, and steam volcanoes. Exoplanetary atmospheres have recently become accessible to observations. This book puts our own climate in the wider context of the trials and tribulations of planetary atmospheres. Based on cutting-edge research, it uses a grand tour of the atmospheres of other planets to shine a new light on our own atmosphere, and its relation with life.

  3. Design and Simulation Tools for Planetary Atmospheric Entry Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric entry is one of the most critical phases of flight during planetary exploration missions. During the design of an entry vehicle, experimental and...

  4. Franklin Lecture: Lightning in Planetary Atmospheres

    Science.gov (United States)

    Gurnett, D. A.

    2006-12-01

    A broad overview is given of lightning in planetary atmospheres. Searches for lightning using spacecraft-borne instrumentation have now been conducted at almost all of the planets in the solar system, the exceptions being Mercury, which has no appreciable atmosphere, and Pluto which has not yet been visited by a spacecraft. The techniques used include (1) imaging observations to detect optical flashes produced by lightning; (2) high-frequency radio measurements to detect the impulsive broadband radio bursts, called spherics, produced by lightning discharges; and (3) low-frequency plasma wave measurements to detect the whistling tones, called whistlers, produced by lightning. Using these techniques, lightning has been reported at five planets other than Earth. These are: Venus, Jupiter, Saturn, Uranus, and Neptune. Of these, the existence of lightning at Venus is doubtful, and the evidence of lightning at Neptune is at best marginal. Jupiter and Saturn have by far the most intense and well documented lightning activity. During the Voyager 1 flyby of Jupiter, whistlers and intense optical flashes, comparable to those from terrestrial superbolts, were observed by the plasma wave and optical imaging instruments. However, no impulsive high-frequency radio bursts were observed. Two factors may be responsible for the absence of high-frequency radio signals: (1) the very strong magnetic field of Jupiter, which blocks the escape of the extra-ordinary mode; and (2) the relatively high electron collision frequency in the ionosphere, which increases the absorption of radio waves. During the Voyager 1 and 2 flybys of Saturn many very strong high-frequency radio bursts, called Saturn Electrostatic Discharges (SEDs), were detected. Although the origin of these impulsive radio bursts was initially uncertain, strong evidence now exists that SEDs are produced by lightning. Recent optical imaging and radio measurements from the Cassini spacecraft clearly show that SEDs originate from

  5. A New Perspective on Trapped Radiation Belts in Planetary Atmospheres

    Science.gov (United States)

    Diaz, A.; Lodhi, M. A. K.; Wilson, T. L.

    2005-01-01

    The charged particle fluxes trapped in the magnetic dipole fields of certain planets in our Solar System are interesting signatures of planetary properties in space physics. They also represent a source of potentially hazardous radiation to spacecraft during planetary and interplanetary exploration. The Earth s trapped radiation belts have been studied for years and the physical mechanisms by which primary radiation from the Sun and Galaxy is captured is well understood. The higher-energy particles collide with molecules in the planetary atmosphere and initiate large cascades of secondary radiation which itself becomes trapped by the magnetic dipole field of the planet. Some of it is even backscattered as albedo neutrons.

  6. Composition of Early Planetary Atmospheres I: Connecting Disk Astrochemistry to the Formation of Planetary Atmospheres

    CERN Document Server

    Cridland, Alex J; Alessi, Matthew

    2016-01-01

    We present a model of early planetary atmospheres which represents the cumulative gaseous chemical species that are accreted onto planets forming by core accretion from an evolving protoplanetary disk. The astrochemistry of the host disk is computed using ionization driven, non-equilibrium chemistry networks within viscously evolving disk models. We accrete gas giant planets whose evolution is controlled by planet traps using the standard core accretion model and track the chemical composition of the material that is accreted onto the protoplanet. We choose a fiducial disk model and evolve planets in 3 traps - water ice line, dead zone and heat transition. For a disk with a lifetime of $4.1$ Myr we produce two Hot Jupiters (M $= 1.43, 2.67$ M$_{\\rm Jupiter}$, r $= 0.15, 0.11$ AU) in the heat transition and ice line trap and one failed core (M $= 0.003$ M$_{\\rm Jupiter}$, r $=3.7$ AU) in the dead zone. These planets are found with mixing ratios for CO and H$_2$O of $1.99\\times 10^{-4}$, $5.0\\times 10^{-4}$ res...

  7. Crossing the Boundaries in Planetary Atmospheres - From Earth to Exoplanets

    Science.gov (United States)

    Simon-Miller, Amy A.; Genio, Anthony Del

    2013-01-01

    The past decade has been an especially exciting time to study atmospheres, with a renaissance in fundamental studies of Earths general circulation and hydrological cycle, stimulated by questions about past climates and the urgency of projecting the future impacts of humankinds activities. Long-term spacecraft and Earth-based observation of solar system planets have now reinvigorated the study of comparative planetary climatology. The explosion in discoveries of planets outside our solar system has made atmospheric science integral to understanding the diversity of our solar system and the potential habitability of planets outside it. Thus, the AGU Chapman Conference Crossing the Boundaries in Planetary Atmospheres From Earth to Exoplanets, held in Annapolis, MD from June 24-27, 2013 gathered Earth, solar system, and exoplanet scientists to share experiences, insights, and challenges from their individual disciplines, and discuss areas in which thinking broadly might enhance our fundamental understanding of how atmospheres work.

  8. Planetary nebulae abundances and stellar evolution II

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2010-01-01

    Context. In recent years mid-and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these objects. Aims. The observed abundances in planetary nebulae are

  9. The NEMESIS planetary atmosphere radiative transfer and retrieval tool

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, P.G.J. [Atmospheric, Oceanic, and Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)], E-mail: irwin@atm.ox.ac.uk; Teanby, N.A.; Kok, R. de; Fletcher, L.N.; Howett, C.J.A.; Tsang, C.C.C.; Wilson, C.F.; Calcutt, S.B. [Atmospheric, Oceanic, and Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Nixon, C.A. [Solar System Exploration Division, University of Maryland/NASA GSFC, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Parrish, P.D. [School of Geosciences, Institute of Atmospheric and Environmental Science, University of Edinburgh, Crew Building, King' s Buildings, Edinburgh EH9 3JN (United Kingdom)

    2008-04-15

    With the exception of in situ atmospheric probes, the most useful way to study the atmospheres of other planets is to observe their electromagnetic spectra through remote observations, either from ground-based telescopes or from spacecraft. Atmospheric properties most consistent with these observed spectra are then derived with retrieval models. All retrieval models attempt to extract the maximum amount of atmospheric information from finite sets of data, but while the problem to be solved is fundamentally the same for any planetary atmosphere, until now all such models have been assembled ad hoc to address data from individual missions. In this paper, we describe a new general-purpose retrieval model, Non-linear Optimal Estimator for MultivariatE Spectral analySIS (NEMESIS), which was originally developed to interpret observations of Saturn and Titan from the composite infrared spectrometer on board the NASA Cassini spacecraft. NEMESIS has been constructed to be generally applicable to any planetary atmosphere and can be applied from the visible/near-infrared right out to microwave wavelengths, modelling both reflected sunlight and thermal emission in either scattering or non-scattering conditions. NEMESIS has now been successfully applied to the analysis of data from many planetary missions and also ground-based observations.

  10. Composition of early planetary atmospheres - I. Connecting disc astrochemistry to the formation of planetary atmospheres

    Science.gov (United States)

    Cridland, A. J.; Pudritz, R. E.; Alessi, M.

    2016-09-01

    We present a model of the early chemical composition and elemental abundances of planetary atmospheres based on the cumulative gaseous chemical species that are accreted on to planets forming by core accretion from evolving protoplanetary discs. The astrochemistry of the host disc is computed using an ionization-driven, non-equilibrium chemistry network within viscously evolving disc models. We accrete gas giant planets whose orbital evolution is controlled by planet traps using the standard core accretion model and track the chemical composition of the material that is accreted on to the protoplanet. We choose a fiducial disc model and evolve planets in three traps - water ice line, dead zone and heat transition. For a disc with a lifetime of 4.1 Myr, we produce two hot Jupiters (M = 1.43, 2.67 MJupiter, r = 0.15, 0.11 au) in the heat transition and ice line trap and one failed core (M = 0.003 MJupiter, r = 3.7 au) in the dead zone. These planets are found with mixing ratios for CO and H2O of 1.99 × 10-4 and 5.0 × 10-4, respectively, for both hot Jupiters. Additionally, for these planets we find CO2 and CH4, with mixing ratios of 1.8 × 10-6 → 9.8 × 10-10 and 1.1 × 10-8 → 2.3 × 10-10, respectively. These ranges correspond well with the mixing ratio ranges that have been inferred through the detection of emission spectra from hot Jupiters by multiple authors. We compute a carbon-to-oxygen ratio of 0.227 for the ice line planet and 0.279 for the heat transition planet. These planets accreted their gas inside the ice line, hence the sub-solar C/O.

  11. Solar system astrophysics planetary atmospheres and the outer solar system

    CERN Document Server

    Milone, Eugene F

    2014-01-01

    The second edition of Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System provides a timely update of our knowledge of planetary atmospheres and the bodies of the outer solar system and their analogs in other planetary systems. This volume begins with an expanded treatment of the physics, chemistry, and meteorology of the atmospheres of the Earth, Venus, and Mars, moving on to their magnetospheres and then to a full discussion of the gas and ice giants and their properties. From here, attention switches to the small bodies of the solar system, beginning with the natural satellites. Then comets, meteors, meteorites, and asteroids are discussed in order, and the volume concludes with the origin and evolution of our solar system. Finally, a fully revised section on extrasolar planetary systems puts the development of our system in a wider and increasingly well understood galactic context. All of the material is presented within a framework of historical importance. This book and its sist...

  12. SOIR and NOMAD: Characterization of Planetary Atmospheres

    Science.gov (United States)

    Robert, S.; Chamberlain, S.; Mahieux, A.; Thomas, I.; Wilquet, V.; Vandaele, A. C.

    2014-06-01

    The Belgian Institute for Space Aeronomy is involved in the Venus Express mission (VeX), launched in 2006 and in the ExoMars Trace Gas Orbiter mission (TGO), due for launch in 2016. BISA is responsible for one instrument in each mission, SOIR onboard VeX and NOMAD onboard TGO respectively. The SOIR instrument onboard Venus Express allows observations of trace gases in the Venus atmosphere, at the terminator for both the morning and evening sides of the planet and for almost all latitudes. It has been designed to measure spectra in the IR region (2.2 - 4.3 µm) of the Venus atmosphere using the solar occultation technique1. This method derives unique information on the vertical composition and structure of the mesosphere and lower thermosphere2,3,4,5. It is unique in terms of spectral coverage and spectral resolution (0.15 cm-1), and is ideally designed to probe the Venus atmosphere for CO2 as well as trace gases, such as H2O, CO, HCl and HF. SOIR is capable of (1) providing vertical information on a broad series of species, such as CO2, CO, H2O, HCl, HF, SO26 and aerosols 7, covering the so far sparsely known region located above the clouds, (2) contributing to a better understanding of the dynamics and stability of the atmosphere by delivering total density and kinetic temperature profiles at the terminator, an up-to-now still unchartered region, and (3) detecting weak absorption bands of rare CO2 isotopologues8, due to the sensitivity of SOIR, the high concentration of CO2 on Venus and the long absorption paths sounded during solar occultations.

  13. A Study on Planetary Atmospheric Circulations using THOR

    Science.gov (United States)

    Mendonça, João; Grosheintz, Luc; Lukas Grimm, Simon; Heng, Kevin

    2015-12-01

    The large variety of planetary parameters observed leads us to think that exoplanets may show a large range of possible climates. It is therefore of the uttermost importance to investigate the influence of astronomical and planetary bulk parameters in driving the atmospheric circulations. In the solar system the results from planetary spacecraft missions have demonstrated how different the planetary climate and atmospheric circulations can be. The study of exoplanets will require probing a far wider range of physical and orbital parameters than the ones of our neighbor planets. For this reason, such a study will involve exploring an even larger diversity of circulation and climate regimes. Our new atmospheric model, THOR, is intended to be extremely flexible and to explore the large diversity of planetary atmospheres.THOR is part of the Exoclimes Simulation Platform, and is a project of the Exoplanet and Exoclimes Group (see www.exoclime.org). THOR solves the complex atmospheric fluid equations in a rotating sphere (fully compressible - nonhydrostatic system) using an icosahedral grid. The main advantages of using our new platform against other recent exoplanet models is that 1) The atmospheric fluid equations are completely represented and no approximations are used that could compromise the physics of the problem; 2) The model uses for the first time in exoplanet studies, a specific icosahedral grid that solves the pole problem; 3) The interface is user friendly and can be easily adapted to a multitude of atmospheric conditions; 4) By using GPU computation, our code greatly improves the typical code running time.We will present and discuss the first detailed results of our simulations, more specifically of two benchmark tests that are a representative sample of the large range of exoplanetary parameters: Earth-like conditions (the Held-Suarez test) and a tidally locked hot-Jupiter. THOR has successfully passed these tests and is able to determine the main

  14. An Analytic Radiative-Convective Model for Planetary Atmospheres

    CERN Document Server

    Robinson, Tyler D; 10.1088/0004-637X/757/1/104

    2012-01-01

    We present an analytic 1-D radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries, (2) worlds with some attenuation of sunli...

  15. On the radiative equilibrium of irradiated planetary atmospheres

    CERN Document Server

    Guillot, Tristan

    2010-01-01

    The evolution of stars and planets is mostly controlled by the properties of their atmosphere. This is particularly true in the case of exoplanets close to their stars, for which one has to account both for an (often intense) irradiation flux, and from an intrinsic flux responsible for the progressive loss of the inner planetary heat. The goals of the present work are to help understanding the coupling between radiative transfer and advection in exoplanetary atmospheres and to provide constraints on the temperatures of the deep atmospheres. This is crucial in assessing whether modifying assumed opacity sources and/or heat transport may explain the inflated sizes of a significant number of giant exoplanets found so far. I use a simple analytical approach inspired by Eddington's approximation for stellar atmospheres to derive a relation between temperature and optical depth valid for plane-parallel static grey atmospheres which are both transporting an intrinsic heat flux and receiving an outer radiation flux. ...

  16. Photochemical hazes in planetary atmospheres: solar system bodies and beyond

    Science.gov (United States)

    Imanaka, Hiroshi; Cruikshank, Dale P.; McKay, Christopher P.

    2015-11-01

    Recent transit observations of exoplanets have demonstrated the possibility of a wide prevalence of haze/cloud layers at high altitudes. Hydrocarbon photochemical haze could be the candidate for such haze particles on warm sub-Neptunes, but the lack of evidence for methane poses a puzzle for such hydrocarbon photochemical haze. The CH4/CO ratios in planetary atmospheres vary substantially from their temperature and dynamics. An understanding of haze formation rates and plausible optical properties in a wide diversity of planetary atmospheres is required to interpret the current and future observations.Here, we focus on how atmospheric compositions, specifically CH4/CO ratios, affect the haze production rates and their optical properties. We have conducted a series of cold plasma experiments to constrain the haze mass production rates from gas mixtures of various CH4/CO ratios diluted either in H2 or N2 atmosphere. The mass production rates in the N2-CH4-CO system are much greater than those in the H2-CH4-CO system. They are rather insensitive to the CH4/CO ratios larger than at 0.3. Significant formation of solid material is observed both in H2-CO and N2-CO systems without CH4 in the initial gas mixtures. The complex refractive indices were derived for haze samples from N2-CH4, H2-CH4, and H2-CO gas mixtures. These are the model atmospheres for Titan, Saturn, and exoplanets, respectively. The imaginary part of the complex refractive indices in the UV-Vis region are distinct among these samples, which can be utilized for modeling these planetary atmospheres.

  17. Modeling Planetary Atmospheric Energy Deposition By Energetic Ions

    Science.gov (United States)

    Parkinson, Christopher; Bougher, Stephen; Gronoff, Guillaume; Barthelemy, Mathieu

    2016-07-01

    The structure, dynamics, chemistry, and evolution of planetary upper atmospheres are in large part determined by the available sources of energy. In addition to the solar EUV flux, the solar wind and solar energetic particle (SEP) events are also important sources. Both of these particle populations can significantly affect an atmosphere, causing atmospheric loss and driving chemical reactions. Attention has been paid to these sources from the standpoint of the radiation environment for humans and electronics, but little work has been done to evaluate their impact on planetary atmospheres. At unmagnetized planets or those with crustal field anomalies, in particular, the solar wind and SEPs of all energies have direct access to the atmosphere and so provide a more substantial energy source than at planets having protective global magnetic fields. Additionally, solar wind and energetic particle fluxes should be more significant for planets orbiting more active stars, such as is the case in the early history of the solar system for paleo-Venus and Mars. Therefore quantification of the atmospheric energy input from the solar wind and SEP events is an important component of our understanding of the processes that control their state and evolution. We have applied a full Lorentz motion particle transport model to study the effects of particle precipitation in the upper atmospheres of Mars and Venus. Such modeling has been previously done for Earth and Mars using a guiding center precipitation model. Currently, this code is only valid for particles with small gyroradii in strong uniform magnetic fields. There is a clear necessity for a Lorentz formulation, hence, a systematic study of the ionization, excitation, and energy deposition has been conducted, including a comparison of the influence relative to other energy sources (namely EUV photons). The result is a robust examination of the influence of energetic ion transport on the Venus and Mars upper atmosphere which

  18. Constructing an advanced software tool for planetary atmospheric modeling

    Science.gov (United States)

    Keller, Richard M.; Sims, Michael; Podolak, Ester; Mckay, Christopher

    1990-01-01

    Scientific model building can be an intensive and painstaking process, often involving the development of large and complex computer programs. Despite the effort involved, scientific models cannot be easily distributed and shared with other scientists. In general, implemented scientific models are complex, idiosyncratic, and difficult for anyone but the original scientist/programmer to understand. We believe that advanced software techniques can facilitate both the model building and model sharing process. In this paper, we describe a prototype for a scientific modeling software tool that serves as an aid to the scientist in developing and using models. This tool includes an interactive intelligent graphical interface, a high level domain specific modeling language, a library of physics equations and experimental datasets, and a suite of data display facilities. Our prototype has been developed in the domain of planetary atmospheric modeling, and is being used to construct models of Titan's atmosphere.

  19. Towards a Carbon Nanotube Ionization Source for Planetary Atmosphere Exploration

    Science.gov (United States)

    Oza, A. V.; Leblanc, F.; Berthelier, J. J.; Becker, J.; Coulomb, R.; Gilbert, P.; Hong, N. T.; Lee, S.; Vettier, L.

    2015-12-01

    The characterization of planetary exospheres today, relies on the development of a highly efficient ionization source, due to the scant neutral molecules (n atmospheres provide insight on to physical processes known to occur such as: space weathering, magneto-atmosphere interactions, as well as atmospheric escape mechanisms, all of which are being heavily investigated via current 3D Monte Carlo simulations (Turc et al. 2014, Leblanc et al. 2016 in prep) at LATMOS. Validation of these studies will rely on in-situ observations in the coming decades. Neutral detection strongly depends on electron-impact ionization which via conventional cathode-sources, such as thermal filaments (heated up to 2000 K), may only produce the target ionization essential for energy-measurements with large power consumption. Carbon nanotubes (CNTs) however are ideal low-power, cold cathodes, when subject to moderate electric fields (E ~ 1 MV / m). We present our current device, a small CNT chip, of emission area 15 mm2, emitting electrons that pass through an anode grid and subsequent electrostatic analyzer. The device currently extracts hundreds of µAmperes with applied external voltages ~ -150 Volts, approaching minimum power consumption plasma sputtering the icy regolith with heavy ions and electrons (keV < E < MeV), producing predominately molecular oxygen (Johnson et al. 2002).

  20. Plasma Flow Past Cometary and Planetary Satellite Atmospheres

    Science.gov (United States)

    Combi, Michael R.; Gombosi, Tamas I.; Kabin, Konstantin

    2000-01-01

    The tenuous atmospheres and ionospheres of comets and outer planet satellites share many common properties and features. Such similarities include a strong interaction with their outer radiation, fields and particles environs. For comets the interaction is with the magnetized solar wind plasma, whereas for satellites the interaction is with the strongly magnetized and corotating planetary magnetospheric plasma. For this reason there are many common or analogous physical regimes, and many of the same modeling techniques are used to interpret remote sensing and in situ measurements in order to study the important underlying physical phenomena responsible for their appearances. We present here a review of various modeling approaches which are used to elucidate the basic properties and processes shaping the energetics and dynamics of these systems which are similar in many respects.

  1. Solar system astrophysics planetary atmospheres and the outer solar system

    CERN Document Server

    Milone, Eugene F

    2008-01-01

    Solar System Astrophysics opens with coverage of the atmospheres, ionospheres and magnetospheres of the Earth, Venus and Mars and the magnetosphere of Mercury. The book then provides an introduction to meteorology and treating the physics and chemistry of these areas in considerable detail. What follows are the structure, composition, particle environments, satellites, and rings of Jupiter, Saturn, Uranus and Neptune, making abundant use of results from space probes. Solar System Astrophysics follows the history, orbits, structure, origin and demise of comets and the physics of meteors and provides a thorough treatment of meteorites, the asteroids and, in the outer solar system, the Kuiper Belt objects. The methods and results of extrasolar planet searches, the distinctions between stars, brown dwarfs, and planets, and the origins of planetary systems are examined. Historical introductions precede the development and discussion in most chapters. A series of challenges, useful as homework assignments or as foc...

  2. Analytical theories for spacecraft entry into planetary atmospheres and design of planetary probes

    Science.gov (United States)

    Saikia, Sarag J.

    This dissertation deals with the development of analytical theories for spacecraft entry into planetary atmospheres and the design of entry spacecraft or probes for planetary science and human exploration missions. Poincare's method of small parameters is used to develop an improved approximate analytical solution for Yaroshevskii's classical planetary entry equation for the ballistic entry of a spacecraft into planetary atmospheres. From this solution, other important expressions are developed including deceleration, stagnation-point heat rate, and stagnation-point integrated heat load. The accuracy of the solution is assessed via numerical integration of the exact equations of motion. The solution is also compared to the classical solutions of Yaroshevskii and Allen and Eggers. The new second-order analytical solution is more accurate than Yaroshevskii's fifth-order solution for a range of shallow (-3 deg) to steep (up to -90 deg) entry flight path angles, thereby extending the range of applicability of the solution as compared to the classical Yaroshevskii solution, which is restricted to an entry flight path of approximately -40 deg. Universal planetary entry equations are used to develop a new analytical theory for ballistic entry of spacecraft for moderate to large initial flight path angles. Chapman's altitude variable is used as the independent variable. Poincare's method of small parameters is used to develop an analytical solution for the velocity and the flight path angle. The new solution is used to formulate key expressions for range, time-of-flight, deceleration, and aerodynamic heating parameters (e.g., stagnation-point heat rate, total stagnation-point heat load, and average heat input). The classical approximate solution of Chapman's entry equation appears as the zero-order term in the new solution. The new solution represents an order of magnitude enhancement in the accuracy compared to existing analytical solutions for moderate to large entry

  3. The Explicit Planetary Isentropic-Coordinate (EPIC) Atmospheric Model

    Science.gov (United States)

    Dowling, T. E.; Fischer, A. S.; Gierasch, P. J.; Harrington, J.; LeBeau, R. P.; Santori, C. M.

    1998-04-01

    We describe a new general circulation model (GCM) designed for planetary atmospheric studies called the EPIC model. This is a finite-difference model based on the isentropic-coordinate scheme of Hsu and Arakawa (1990.Mon. Wea. Rev.118, 1933-1959). We report on previously undocumented modifications, additions, and key practical issues that experience running the model has revealed to be important. The model integrates the hydrostatic primitive equations, which are valid for large-scale atmospheric dynamics and include gravity waves (buoyancy waves), planetary waves (Rossby waves), and horizontally propagating sound waves (Lamb waves), but not vertically propagating sound waves because of the hydrostatic approximation. The vertical coordinate is entropy in the form of potential temperature, which coincides with material surfaces for adiabatic motion. This means that there is no vertical velocity except where there is heating, which improves accuracy and helps the model maintain conservation properties over long integrations. An isentropic vertical coordinate is natural for the atmospheres of Jupiter, Saturn, Uranus, and Neptune, which are believed to have essentially adiabatic interiors that match up with the bottom of the model and is also excellent for middle-atmosphere studies on any planet. Radiative processes are parameterized by Newtonian cooling, and the latent heat of ortho-para hydrogen conversion is included when appropriate, with a suitably defined mean potential temperature. The model is written with general map factors that make it easy to configure in oblate spherical, cylindrical, or Cartesian coordinates. The code includes optional Message Passing Interface (MPI) library calls and hence runs on any Unix-based parallel computer or network cluster. An optional graphical user interface to commercial visualization software facilitates control of the model and analysis of output. Memory is allocated dynamically such that the user does not recompile to

  4. Plasma-induced Escape and Alterations of Planetary Atmospheres

    Science.gov (United States)

    Johnson, R. E.; Tucker, O. J.; Ewrin, J.; Cassidy, T. A.; Leblanc, F.

    2009-12-01

    The atmospheres of planets and planetary satellites are typically imbedded in space plasmas. Depending on the interaction with the induced or intrinsic fields energetic ions can have access to the thermosphere and the corona affecting their composition and thermal structure and causing loss to space. These processes are often lumped together as ‘atmospheric sputtering’ (Johnson 1994). In this talk I will review the results of simulations of the plasma bombardment at a number of solar system bodies and use those data to describe the effect on the upper atmosphere and on escape. Of considerable recent interest is the modeling of escape from Titan. Prior to Cassini’s tour of the Saturnian system, plasma-induced escape was suggested to be the dominant loss process, but recent models of enhanced thermal escape, often referred to as ‘slow hydrodynamic’ escape, have been suggested to lead to much larger Titan atmospheric loss rates (Strobel 2008; Cui et al. 2008). Such a process has been suggested to be active at some point in time on a number of solar system bodies. I will present hybrid fluid/ kinetic models of the upper atmosphere of certain bodies in order to test both the plasma-induced and thermal escape processes. Preliminary results suggest that the loss rates estimated using the ‘slow hydrodynamic’ escape process can be orders of magnitude too large. The implications for Mars, Titan and Pluto will be discussed. Background for this talk is contained in the following papers (Johnson 2004; 2009; Chaufray et al. 2007; Johnson et al. 2008; 2009; Tucker and Johnson 2009). References: Chaufray, J.Y., R. Modolo, F. Leblanc, G. Chanteur, R.E. Johnson, and J.G. Luhmann, Mars Solar Wind interaction: formation of the Martian corona and atmosphric loss to space, JGR 112, E09009, doi:10.1029/2007JE002915 (2007) Cui, J., Yelle, R. V., Volk, K. Distribution and escape of molecular hydrogen in Titan's thermosphere and exosphere. J. Geophys. Res. 113, doi:10

  5. On the parametrization of the planetary boundary layer of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, D. [Bulgarian Academy of Sciences, Geophysical Inst., Sofia (Bulgaria); Syrakov, D.; Kolarova, M. [Bulgarian Academy of Sciences, National Inst. of Meteorology and Hydrology, Sofia (United Kingdom)

    1997-10-01

    The investigation of the dynamic processes in the planetary boundary layer presents a definite theoretical challenge and plays a growing role for the solution of a number of practical tasks. The improvement of large-scale atmospheric weather forecast depends, to a certain degree, on the proper inclusion of the planetary boundary layer dynamics in the numerical models. The modeling of the transport and the diffusion of air pollutants is connected with estimation of the different processes in the Planetary Boundary Layer (PBL) and needs also a proper PBL parametrization. For the solution of these practical tasks the following PBL models;(i) a baroclinic PBL model with its barotropic version, and (ii) a convective PBL model were developed. Both models are one dimensional and are based on the similarity theory and the resistance lows extended for the whole PBL. Two different PBL parametrizations under stable and under convective conditions are proposed, on the basis of which the turbulent surface heat and momentum fluxes are estimated using generalized similarity theory. By the proposed parametrizations the internal parameters are calculated from the synoptic scale parameters as geostrophyc wind, potential temperature and humidity given at two levels (ground level and at 850 hPa) and from them - the PBL profiles. The models consists of two layers: a surface layer (SL) with a variable height and a second (Ekman layer) over it with a constant with height turbulent exchange coefficient. (au) 14 refs.

  6. The applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research

    Science.gov (United States)

    Fegley, Bruce, Jr.

    1990-01-01

    A review of the applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research during the past four decades is presented with an emphasis on chemical equilibrium models and thermochemical kinetics. Several current problems in planetary atmospheres research such as the origin of the atmospheres of the terrestrial planets, atmosphere-surface interactions on Venus and Mars, deep mixing in the atmospheres of the gas giant planets, and the origin of the atmospheres of outer planet satellites all require laboratory data on the kinetics of thermochemical reactions for their solution.

  7. The applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research

    Science.gov (United States)

    Fegley, Bruce, Jr.

    1990-05-01

    A review of the applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research during the past four decades is presented with an emphasis on chemical equilibrium models and thermochemical kinetics. Several current problems in planetary atmospheres research such as the origin of the atmospheres of the terrestrial planets, atmosphere-surface interactions on Venus and Mars, deep mixing in the atmospheres of the gas giant planets, and the origin of the atmospheres of outer planet satellites all require laboratory data on the kinetics of thermochemical reactions for their solution.

  8. Effects of the seasonal cycle on superrotation in planetary atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Jonathan L. [Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095 (United States); Vallis, Geoffrey K. [College of Engineering, Mathematics and Physical Science, Exeter University, Exeter (United Kingdom); Potter, Samuel F. [Atmospheric and Oceanic Sciences Program, Princeton University, NJ 08544 (United States)

    2014-05-20

    The dynamics of dry atmospheric general circulation model simulations forced by seasonally varying Newtonian relaxation are explored over a wide range of two control parameters and are compared with the large-scale circulation of Earth, Mars, and Titan in their relevant parameter regimes. Of the parameters that govern the behavior of the system, the thermal Rossby number (Ro) has previously been found to be important in governing the spontaneous transition from an Earth-like climatology of winds to a superrotating one with prograde equatorial winds, in the absence of a seasonal cycle. This case is somewhat unrealistic as it applies only if the planet has zero obliquity or if surface thermal inertia is very large. While Venus has nearly vanishing obliquity, Earth, Mars, and Titan (Saturn) all have obliquities of ∼25° and varying degrees of seasonality due to their differing thermal inertias and orbital periods. Motivated by this, we introduce a time-dependent Newtonian cooling to drive a seasonal cycle using idealized model forcing, and we define a second control parameter that mimics non-dimensional thermal inertia of planetary surfaces. We then perform and analyze simulations across the parameter range bracketed by Earth-like and Titan-like regimes, assess the impact on the spontaneous transition to superrotation, and compare Earth, Mars, and Titan to the model simulations in the relevant parameter regime. We find that a large seasonal cycle (small thermal inertia) prevents model atmospheres with large thermal Rossby numbers from developing superrotation by the influences of (1) cross-equatorial momentum advection by the Hadley circulation and (2) hemispherically asymmetric zonal-mean zonal winds that suppress instabilities leading to equatorial momentum convergence. We also demonstrate that baroclinic instabilities must be sufficiently weak to allow superrotation to develop. In the relevant parameter regimes, our seasonal model simulations compare favorably to

  9. On the averaging of ratios of specific heats in a multicomponent planetary atmosphere

    Science.gov (United States)

    Dubisch, R.

    1974-01-01

    The use of adiabatic relations in the calculation of planetary atmospheres requires knowledge of the ratio of specific heats of a mixture of gases under various pressure and temperature conditions. It is shown that errors introduced by simple averaging of the ratio of specific heats in a multicomponent atmosphere can be roughly 0.4%. Therefore, the gamma-averaging error can become important when integrating through the atmosphere to a large depth.

  10. On detecting biospheres from thermodynamic disequilibrium in planetary atmospheres

    CERN Document Server

    Krissansen-Totton, Joshua; Catling, David C

    2015-01-01

    Atmospheric chemical disequilibrium has been proposed as a method for detecting extraterrestrial biospheres from exoplanet observations. Chemical disequilibrium is potentially a generalized biosignature since it makes no assumptions about particular biogenic gases or metabolisms. Here, we present the first rigorous calculations of the thermodynamic chemical disequilibrium in the atmospheres of Solar System planets, in which we quantify the difference in Gibbs free energy of an observed atmosphere compared to that of all the atmospheric gases reacted to equilibrium. The purely gas phase disequilibrium in Earth's atmosphere, as measured by this available Gibbs free energy, is not unusual by Solar System standards and smaller than that of Mars. However, Earth's atmosphere is in contact with a surface ocean, which means that gases can react with water, and so a multiphase calculation that includes aqueous species is required. We find that the disequilibrium in Earth's atmosphere-ocean system (in joules per mole o...

  11. Eddy heat fluxes and stability of planetary waves. I, II

    Science.gov (United States)

    Lin, C. A.

    1980-01-01

    The stability of baroclinic Rossby waves in a zonal shear flow was analyzed by a linear, quasigeostrophic, two-level, adiabatic, and frictionless midlatitude beta-plane model. The ratio of the basic wave scale and the radius of deformation together with two nondimensional parameters which describe the amplitudes of the barotropic and baroclinic components of the basic wave constitute the three parameters of the stability problem. The parameter space is partitioned according to the dominant energy source for instability; the Lorenz and Kim conditions are characterized by significant horizontal and vertical shears of the basic wave, while the Phillips regime has a strong zonal flow. The stability analysis is then applied to the atmosphere, with the primary motivation being to examine the midlatitude planetary scale (zonal wavenumbers 1, 2, 3) transient waves that transport heat. It is found that the most unstable mode consists of a spectrum of waves, with a maximum amplitude at wavenumber 3; the response is thus maximum at a zonal scale intermediate between the basic wave scale and the radius of deformation.

  12. On Detecting Biospheres from Chemical Thermodynamic Disequilibrium in Planetary Atmospheres.

    Science.gov (United States)

    Krissansen-Totton, Joshua; Bergsman, David S; Catling, David C

    2016-01-01

    Atmospheric chemical disequilibrium has been proposed as a method for detecting extraterrestrial biospheres from exoplanet observations. Chemical disequilibrium is potentially a generalized biosignature since it makes no assumptions about particular biogenic gases or metabolisms. Here, we present the first rigorous calculations of the thermodynamic chemical disequilibrium in Solar System atmospheres, in which we quantify the available Gibbs energy: the Gibbs free energy of an observed atmosphere minus that of atmospheric gases reacted to equilibrium. The purely gas phase disequilibrium in Earth's atmosphere is mostly attributable to O2 and CH4. The available Gibbs energy is not unusual compared to other Solar System atmospheres and smaller than that of Mars. However, Earth's fluid envelope contains an ocean, allowing gases to react with water and requiring a multiphase calculation with aqueous species. The disequilibrium in Earth's atmosphere-ocean system (in joules per mole of atmosphere) ranges from ∼20 to 2 × 10(6) times larger than the disequilibria of other atmospheres in the Solar System, where Mars is second to Earth. Only on Earth is the chemical disequilibrium energy comparable to the thermal energy per mole of atmosphere (excluding comparison to Titan with lakes, where quantification is precluded because the mean lake composition is unknown). Earth's disequilibrium is biogenic, mainly caused by the coexistence of N2, O2, and liquid water instead of more stable nitrate. In comparison, the O2-CH4 disequilibrium is minor, although kinetics requires a large CH4 flux into the atmosphere. We identify abiotic processes that cause disequilibrium in the other atmospheres. Our metric requires minimal assumptions and could potentially be calculated from observations of exoplanet atmospheres. However, further work is needed to establish whether thermodynamic disequilibrium is a practical exoplanet biosignature, requiring an assessment of false positives, noisy

  13. Exact results in modeling planetary atmospheres-III

    Energy Technology Data Exchange (ETDEWEB)

    Pelkowski, J. [Institut fuer Atmosphaere und Umwelt, J.W. Goethe Universitaet Frankfurt, Campus Riedberg, Altenhoferallee 1, D-60438 Frankfurt a.M. (Germany)], E-mail: Pelkowski@meteor.uni-frankfurt.de; Chevallier, L. [Observatoire de Paris-Meudon, Laboratoire LUTH, 5 Place Jules Janssen, 92195 Meudon cedex (France); Rutily, B. [Universite de Lyon, F-69003 Lyon (France); Universite Lyon 1, Observatoire de Lyon, 9 avenue Charles Andre, F-69230 Saint-Genis-Laval (France); CNRS, UMR 5574, Centre de Recherche Astrophysique de Lyon (France); Ecole Normale Superieure de Lyon, F-69007 Lyon (France); Titaud, O. [Centro de Modelamiento Matematico, UMI 2807 CNRS-UChile, Blanco Encalada 2120 - 7 Piso, Casilla 170 - Correo 3, Santiago (Chile)

    2008-01-15

    We apply the semi-gray model of our previous paper to the particular case of the Earth's atmosphere, in order to illustrate quantitatively the inverse problem associated with the direct problem we dealt with before. From given climatological values of the atmosphere's spherical albedo and transmittance for visible radiation, the single-scattering albedo and the optical thickness in the visible are inferred, while the infrared optical thickness is deduced for given global average surface temperature. Eventually, temperature distributions in terms of the infrared optical depth will be shown for a terrestrial atmosphere assumed to be semi-gray and, locally, in radiative and thermodynamic equilibrium.

  14. Atmospheric Breathing Electric Thruster for Planetary Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This study will investigate the development of an atmosphere-breathing electric propulsion solar-powered vehicle to explore planets such as Mars. The vehicle would...

  15. Origin and Evolution of Planetary Atmospheres Implications for Habitability

    CERN Document Server

    Lammer, Helmut

    2013-01-01

    Based on the author’s own work and results obtained by international teams he coordinated, this SpringerBrief offers a concise discussion of the origin and early evolution of atmospheres of terrestrial planets during the active phase of their host stars, as well as of the environmental conditions which are necessary in order for planets like the Earth to obtain N_2-rich atmospheres. Possible thermal and non-thermal atmospheric escape processes are discussed in a comparative way between the planets in the Solar System and exoplanets. Lastly, a hypothesis for how to test and study the discussed atmosphere evolution theories using future UV transit observations of terrestrial exoplanets within the orbits of dwarf stars is presented.

  16. Band absorption in nonhomogeneous, isotropically-scattering planetary atmospheres - Theory and experiment

    Science.gov (United States)

    Page, W. A.; Sutton, R. E.; Miller, R. J.

    1973-01-01

    A computer program is developed which predicts the vertical distribution of an absorbing species in an isotropically-scattering, finite planetary atmosphere from measurements of the upwelling band radiance determined by a vertically traversing 2-channel radiometer. Comparison is made with experiment.

  17. Numerical model of a non-steady atmospheric planetary boundary layer, based on similarity theory

    DEFF Research Database (Denmark)

    Zilitinkevich, S.S.; Fedorovich, E.E.; Shabalova, M.V.

    1992-01-01

    A numerical model of a non-stationary atmospheric planetary boundary layer (PBL) over a horizontally homogeneous flat surface is derived on the basis of similarity theory. The two most typical turbulence regimes are reproduced: one corresponding to a convectively growing PBL and another correspon...

  18. On the Nature, Theory, and Modeling of Atmospheric Planetary Boundary Layers

    DEFF Research Database (Denmark)

    Baklanov, Alexander A.; Grisogono, Branko; Bornstein, Robert

    2011-01-01

    The gap between our modern understanding of planetary boundary layer physics and its decades-old representations in current operational atmospheric models is widening, which has stimulated this review of the current state of the art and an analysis of the immediate needs in boundary layer theory...

  19. Wide-Band Heterodyne Submillimetre Wave Spectrometer for Planetary Atmospheres

    Science.gov (United States)

    Schlecht, Erich

    2010-01-01

    We present calculations and measurements on a passive submillimetre wave spectroscopic sounder to gather data on the thermal structure, dynamics and composition of the upper atmosphere of a planet, e.g. the stratosphere of Jupiter, or the entire thickness of the atmosphere of Mars. The instrument will be capable of measuring wind speeds, temperature, pressure, and key constituent concentrations in the stratosphere of the target planet. This instrument consists of a Schottky diode based front end and a digital back-end spectrometer. It differs from previous space-based spectrometers in its combination of wide tunability (520-590 GHz), and rapid frequency switching between widely spaced lines within that range. This will enable near simultaneous observation of multiple lines, which is critical to the reconstruction of atmospheric pressure and density versus altitude profiles. At the same time frequency accuracy must be high to enable wind speeds to be determined directly by measurement of the line's Doppler shift.

  20. Planetary Atmosphere and Surfaces Chamber (PASC): A Platform to Address Various Challenges in Astrobiology

    Science.gov (United States)

    Mateo-Marti, Eva

    2014-08-01

    The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres' conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces. Furthermore, the

  1. Planetary Data Systems (PDS) Imaging Node Atlas II

    Science.gov (United States)

    Stanboli, Alice; McAuley, James M.

    2013-01-01

    The Planetary Image Atlas (PIA) is a Rich Internet Application (RIA) that serves planetary imaging data to the science community and the general public. PIA also utilizes the USGS Unified Planetary Coordinate system (UPC) and the on-Mars map server. The Atlas was designed to provide the ability to search and filter through greater than 8 million planetary image files. This software is a three-tier Web application that contains a search engine backend (MySQL, JAVA), Web service interface (SOAP) between server and client, and a GWT Google Maps API client front end. This application allows for the search, retrieval, and download of planetary images and associated meta-data from the following missions: 2001 Mars Odyssey, Cassini, Galileo, LCROSS, Lunar Reconnaissance Orbiter, Mars Exploration Rover, Mars Express, Magellan, Mars Global Surveyor, Mars Pathfinder, Mars Reconnaissance Orbiter, MESSENGER, Phoe nix, Viking Lander, Viking Orbiter, and Voyager. The Atlas utilizes the UPC to translate mission-specific coordinate systems into a unified coordinate system, allowing the end user to query across missions of similar targets. If desired, the end user can also use a mission-specific view of the Atlas. The mission-specific views rely on the same code base. This application is a major improvement over the initial version of the Planetary Image Atlas. It is a multi-mission search engine. This tool includes both basic and advanced search capabilities, providing a product search tool to interrogate the collection of planetary images. This tool lets the end user query information about each image, and ignores the data that the user has no interest in. Users can reduce the number of images to look at by defining an area of interest with latitude and longitude ranges.

  2. Planetary Probe Entry Atmosphere Estimation Using Synthetic Air Data System

    Science.gov (United States)

    Karlgaard, Chris; Schoenenberger, Mark

    2017-01-01

    This paper develops an atmospheric state estimator based on inertial acceleration and angular rate measurements combined with an assumed vehicle aerodynamic model. The approach utilizes the full navigation state of the vehicle (position, velocity, and attitude) to recast the vehicle aerodynamic model to be a function solely of the atmospheric state (density, pressure, and winds). Force and moment measurements are based on vehicle sensed accelerations and angular rates. These measurements are combined with an aerodynamic model and a Kalman-Schmidt filter to estimate the atmospheric conditions. The new method is applied to data from the Mars Science Laboratory mission, which landed the Curiosity rover on the surface of Mars in August 2012. The results of the new estimation algorithm are compared with results from a Flush Air Data Sensing algorithm based on onboard pressure measurements on the vehicle forebody. The comparison indicates that the new proposed estimation method provides estimates consistent with the air data measurements, without the use of pressure measurements. Implications for future missions such as the Mars 2020 entry capsule are described.

  3. Gamma-ray bursts and terrestrial planetary atmospheres

    CERN Document Server

    Thomas, B C; Thomas, Brian C.; Melott, Adrian L.

    2006-01-01

    We describe results of modeling the effects of gamma-ray bursts (GRBs) within a few kiloparsecs of an Earth-like planet. A primary effect is generation of nitrogen oxide compounds which deplete ozone. Ozone depletion leads to an increase in solar UVB radiation at the surface, enhancing DNA damage, particularly in marine microorganisms such as phytoplankton. In addition, we expect increased atmospheric opacity due to buildup of nitrogen dioxide produced by the burst and enhanced precipitation of nitric acid. We review here previous work on this subject and discuss recent developments.

  4. Planetary Entry Probes and Mass Spectroscopy: Tools and Science Results from In Situ Studies of Planetary Atmospheres and Surfaces

    Science.gov (United States)

    Niemann, Hasso B.

    2007-01-01

    Probing the atmospheres and surfaces of the planets and their moons with fast moving entry probes has been a very useful and essential technique to obtain in situ or quasi in situ scientific data (ground truth) which could not otherwise be obtained from fly by or orbiter only missions and where balloon, aircraft or lander missions are too complex and costly. Planetary entry probe missions have been conducted successfully on Venus, Mars, Jupiter and Titan after having been first demonstrated in the Earth's atmosphere. Future missions will hopefully also include more entry probe missions back to Venus and to the outer planets. 1 he success of and science returns from past missions, the need for more and better data, and a continuously advancing technology generate confidence that future missions will be even more successful with respect to science return and technical performance. I'he pioneering and tireless work of Al Seiff and his collaborators at the NASA Ames Research Center had provided convincing evidence of the value of entry probe science and how to practically implement flight missions. Even in the most recent missions involving entry probes i.e. Galileo and Cassini/Huygens A1 contributed uniquely to the science results on atmospheric structure, turbulence and temperature on Jupiter and Titan.

  5. Planetary Atmosphere and Surfaces Chamber (PASC: A Platform to Address Various Challenges in Astrobiology

    Directory of Open Access Journals (Sweden)

    Eva Mateo-Marti

    2014-08-01

    Full Text Available The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres’ conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces

  6. Dissociative recombination in reactive flows related to planetary atmospheric entries

    Directory of Open Access Journals (Sweden)

    Bultel Arnaud

    2015-01-01

    Full Text Available The Dissociative Recombination (DR processes play a significant role in plasma chemistry. This article illustrates this role from the modeling point of view in the case of reactive flows related to atmospheric entry plasmas. Two situations are investigated, for which the studied plasma is nitrogen. The first configuration corresponds to the relaxation process behind a strong shock wave moving at high Mach number in a shock tube, the second one to the recombination taking place in an expanding plasma flowing in a diverging nozzle. In both cases, the collisional-radiative model CoRaM-N2, involving N2, N, N2+, N+ and electrons, is implemented in an Eulerian 1D code able to compute the aerodynamic fields; calculations are performed in standard conditions. We show that, according to the rate coefficients used for the DR processes, the population density of the charged species especially N2+ is strongly modified only for the post-shock flow.

  7. Probing the extreme planetary atmosphere of WASP-12b

    CERN Document Server

    Swain, Mark; Tinetti, Giovanna; Hollis, Morgan; Tessenyi, Marcell; Line, Michael; Kawahara, Hajime; Fujii, Yuka; Showman, Adam; Yurchenko, Sergey

    2012-01-01

    We report near-infrared measurements of the terminator region transmission spectrum and dayside emission spectrum of the exoplanet WASP-12b obtained using the HST WFC3 instrument. The disk-average dayside brightness temperature averages about 2900 K, peaking to 3200 K around 1.46 {\\mu}m. Both the dayside and terminator region spectra can be explained in terms of opacity due to the metal hydrides CrH and TiH together with a dayside temperature inversion with a deep tropopause. Although our measurements do not constrain the C/O ratio, the combination of TiH and high temperatures could imply the atmosphere of WASP-12b may be significantly metal poor. The dayside flux distribution reconstructed from the ingress light-curve shape shows indications of a hotspot. If located along the equatorial plane, the possible hot spot is near the sub-stellar point, indicating the radiative time scale may be shorter than the advection time scale. We also find the near-infrared primary eclipse light curve is consistent with small...

  8. Optical and Hygroscopic Studies of Aerosols In Simulated Planetary Atmospheres

    Science.gov (United States)

    Hasenkopf, Christa A.

    2011-08-01

    Basic characteristics of the early Earth climate, the only known environment in the Universe in which life has been known to emerge and thrive, remain a mystery. In particular, little is understood about the Earth's atmosphere 2.8 billion years ago. From climate models and laboratory studies, it is postulated that an organic haze, much like that found on Saturn's largest moon Titan, covered the early Earth. This haze, generated from photolysis of carbon dioxide (CO2) and methane (CH4), may have had profound climatic consequences. Climate models of the early Earth that include this haze have had to rely upon optical properties of a Titan laboratory analog. Titan haze, though thought to be similar, is formed from a different combination of precursor gases and by different energy sources than early Earth haze. This thesis examines the direct and indirect radiative effects of aerosol on early Earth climate by studying the optical and hygroscopic properties of a laboratory analog. A Titan analog is studied for comparison and to better understand spacecraft-retrieved haze chemical and optical properties from Titan. The properties of the laboratory analogs, generated in a flowing reactor cell with a continuum ultraviolet (UV) light source, were primarily measured using cavity ringdown aerosol extinction spectroscopy and UV-visible (UV-Vis) transmission spectroscopy. We find that the optical properties of our early Earth analog are significantly different than those of the Titan analog from Khare et al. (1984). In both the UV and visible, when modeled as fractals, particles with the optical properties of the early Earth analog have approximately 30% larger extinction efficiencies than particles with Khare et al. (1984) values. This result implies our early Earth haze analog would provide a more efficient UV shield and have a stronger antigreenhouse effect than the Khare et al. (1984) Titan analog. Our Titan analog has significantly smaller imaginary refractive index values

  9. Decadal regime shift linkage between global marine fish landings and atmospheric planetary wave forcing

    Science.gov (United States)

    Powell, A. M., Jr.; Xu, J.

    2015-04-01

    This investigation focuses on a global forcing mechanism for decadal regime shifts and their subsequent impacts. The proposed global forcing mechanism is that the global atmospheric planetary waves can lead to changes in the global surface air-sea conditions and subsequently fishery changes. In this study, the five decadal regime shifts (1956-1957, 1964-1965, 1977-1978, 1988-1989, and 1998-1999) in the most recent 59-year period (1950-2008) have been identified based on Student t tests and their association with global marine ecosystem change has been discussed. Changes in the three major oceanic (Pacific, Atlantic, and Indian) ecosystems will be explored with the goal of demonstrating the linkage between stratospheric planetary waves and the ocean surface forcing that leads to fisheries impacts. The global forcing mechanism is described with a top-down approach to help the multidisciplinary audience follow the analysis. Following previous work, this analysis addresses how changes in the atmospheric planetary waves may influence the vertical wind structure, surface wind stress, and their connection with the global ocean ecosystems based on a coupling of the atmospheric regime shifts with the decadal regime shifts determined from marine life changes. The multiple decadal regime shifts related to changes in marine life are discussed using the United Nations Food and Agriculture Organization's (FAO) global fish capture data (catch/stock). Analyses are performed to demonstrate that examining the interactions between the atmosphere, ocean, and fisheries is a plausible approach to explaining decadal climate change in the global marine ecosystems and its impacts. The results show a consistent mechanism, ocean wind stress, responsible for marine shifts in the three major ocean basins. Changes in the planetary wave pattern affect the ocean wind stress patterns. A change in the ocean surface wind pattern from longwave (relatively smooth and less complex) to shorter

  10. Decadal regime shift linkage between global marine fish landings and atmospheric planetary wave forcing

    Directory of Open Access Journals (Sweden)

    A. M. Powell Jr.

    2014-08-01

    Full Text Available This investigation focuses on a global forcing mechanism for decadal regime shifts and their subsequent impacts. The proposed global forcing mechanism is the global atmospheric planetary waves that can lead to changes in the global surface air–sea conditions and subsequently fishery changes. In this study, the five decadal regime shifts (1956–1957, 1964–1965, 1977–1978, 1988–1989, and 1998–1999 in the recent 59 years (1950–2008 have been identified based on student t tests and their association with global marine ecosystem change has been discussed. Changes in the three major oceanic (Pacific, Atlantic and Indian ecosystems will be explored with the goal of demonstrating the linkage between stratospheric planetary waves and the ocean surface forcing that leads to fisheries impacts. Due to the multidisciplinary audience, the global forcing mechanism is described from a top-down approach to help the multidisciplinary audience follow the analysis. Following previous work, this analysis addresses how changes in the atmospheric planetary waves may influence the vertical wind structure, surface wind stress, and their connection with the global ocean ecosystems based on a coupling of the atmospheric regime shifts with the decadal regime shifts determined from marine life changes. The multiple decadal regime shifts related to changes in marine life are discussed using the United Nations Food and Agriculture Organization's (FAO global fish capture data (catch/stock. Analyses are performed to demonstrate the interactions between the atmosphere, ocean, and fisheries are a plausible approach to explaining decadal climate change in the global marine ecosystems and its impacts. The results show a consistent mechanism, ocean wind stress, responsible for marine shifts in the three major ocean basins. Changes in the planetary wave pattern affect the ocean wind stress patterns. A change in the ocean surface wind pattern from long wave (relatively

  11. Detecting planetary geochemical cycles on exoplanets: Atmospheric signatures and the case of SO2

    CERN Document Server

    Kaltenegger, L

    2009-01-01

    We study the spectrum of a planetary atmosphere to derive detectable features in low resolution of different global geochemical cycles - using the sulfur cycle as our example to derive detectable features for first generation space- and ground- based telescopes that will characterize exoplanets. We assume that the surfaces and atmospheres of terrestrial exoplanets (Earth-like and super-Earths) will most often be dominated by a specific geochemical cycle. The sulfur cycle driven by outgassing of SO2 and H2S followed by their transformation to other sulfur-bearing species is clearly distinguishable from the carbon cycle which is driven by outgassing of CO2. We calculate planetary emission reflection and transmission spectrum from 0.4 to 40 micron with high and low resolution to assess detectable features for current and Archean Earth with varying SO2 and H2S concentrations. We find specific spectral signatures that are observable in a planetary atmosphere with high SO2 concentration. Therefore future measuremen...

  12. Primordial atmosphere incorporation in planetary embryos and the origin of Neon in terrestrial planets

    Science.gov (United States)

    Jaupart, Etienne; Charnoz, Sebatien; Moreira, Manuel

    2017-09-01

    The presence of Neon in terrestrial planet mantles may be attributed to the implantation of solar wind in planetary precursors or to the dissolution of primordial solar gases captured from the accretionary disk into an early magma ocean. This is suggested by the Neon isotopic ratio similar to those of the Sun observed in the Earth mantle. Here, we evaluate the second hypothesis. We use general considerations of planetary accretion and atmospheric science. Using current models of terrestrial planet formation, we study the evolution of standard planetary embryos with masses in a range of 0.1-0.2 MEarth, where MEarth is the Earth's mass, in an annular region at distances between 0.5 and 1.5 Astronomical Units from the star. We determine the characteristics of atmospheres that can be captured by such embryos for a wide range of parameters and calculate the maximum amount of Neon that can be dissolved in the planet. Our calculations may be directly transposed to any other planet. However, we only know of the amount of Neon in the Earth's solid mantle. Thus we use Earth to discuss our results. We find that the amount of dissolved Neon is too small to account for the present-day Neon contents of the Earth's mantle, if the nebular gas disk completely disappears before the largest planetary embryos grow to be ∼0.2 MEarth. This leaves solar irradiation as the most likely source of Neon in terrestrial planets for the most standard case of planetary formation models.

  13. The circulation pattern and day-night heat transport in the atmosphere of a synchronously rotating aquaplanet: Dependence on planetary rotation rate

    Science.gov (United States)

    Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Takehiro, S.; Onishi, M.; Hashimoto, G. L.; Kuramoto, K.; Hayashi, Y.-Y.

    2017-01-01

    In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aquaplanet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-III to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the

  14. A Mechanism for Land-Atmosphere Feedback Involving Planetary Wave Structures

    Science.gov (United States)

    Koster, Randal D.; Chang, Yehui; Schubert, Siegfried D.

    2014-01-01

    While the ability of land surface conditions to influence the atmosphere has been demonstrated in various modeling and observational studies, the precise mechanisms by which land-atmosphere feedback occurs are still largely unknown particularly the mechanisms that allow land moisture state in one region to affect atmospheric conditions in another. Such remote impacts are examined here in the context of atmospheric general circulation model (AGCM) simulations, leading to the identification of one potential mechanism: the phase-locking and amplification of a planetary wave through the imposition of a spatial pattern of soil moisture at the land surface. This mechanism, shown here to be relevant in the AGCM, apparently also operates in nature, as suggested by supporting evidence found in reanalysis data.

  15. The spectroscopic search for the trace aerosols in the planetary atmospheres - the results of numerical simulations

    Science.gov (United States)

    Blecka, Maria I.

    2010-05-01

    The passive remote spectrometric methods are important in examinations the atmospheres of planets. The radiance spectra inform us about values of thermodynamical parameters and composition of the atmospheres and surfaces. The spectral technology can be useful in detection of the trace aerosols like biological substances (if present) in the environments of the planets. We discuss here some of the aspects related to the spectroscopic search for the aerosols and dust in planetary atmospheres. Possibility of detection and identifications of biological aerosols with a passive InfraRed spectrometer in an open-air environment is discussed. We present numerically simulated, based on radiative transfer theory, spectroscopic observations of the Earth atmosphere. Laboratory measurements of transmittance of various kinds of aerosols, pollens and bacterias were used in modeling.

  16. Superrotation planetary atmospheres: Mechanical analogy, angular momentum budget and simulation of the spin up process

    Science.gov (United States)

    Mayr, H. G.; Harris, I.; Conrath, B. J.

    1981-01-01

    Superrotation rates observed in planetary atmospheres are analyzed based on the concept of a thermally driven zonally symmetric circulation. Specifically, how this superrotation is produced and maintained against the tendency for friction to oppose differential motions between the atmosphere and the underlying planet is addressed. The time evolution of a fluid leading from corotation under uniform heating to superrotation under globally nonuniform heating is simulated using a three dimensional zonally symmetric spectral model and Laplace transformation. The increased tendency toward geostrophy combined with the increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. The resulting viscous shear near the surface thus permits angular momentum to flow from the planet into the atmosphere where it propagates upwards and, combined with the change in moment of inertia, produces large superrotation rates at higher viscosities.

  17. The Chandra planetary nebula survey (CHANPLANS). II. X-ray emission from compact planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.; Kastner, J. H. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Montez, R. Jr. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Jones, D. [Departamento de Física, Universidad de Atacama, Copayapu 485, Copiapó (Chile); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía s/n, Granada, E-18008 (Spain); Lopez, J. A. [Instituto de Astronomía, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Bujarrabal, V. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Corradi, R. L. M. [Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Nordhaus, J. [NSF Astronomy and Astrophysics Fellow, Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); and others

    2014-10-20

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (CHANPLANS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ∼1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. CHANPLANS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. CHANPLANS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R {sub neb} ≲ 0.4 pc), young PNe that lie within ∼1.5 kpc. Results from these Cycle 14 observations include first-time X-ray detections of hot bubbles within NGC 1501, 3918, 6153, and 6369, and point sources in HbDs 1, NGC 6337, and Sp 1. The addition of the Cycle 14 results brings the overall CHANPLANS diffuse X-ray detection rate to ∼27% and the point source detection rate to ∼36%. It has become clearer that diffuse X-ray emission is associated with young (≲ 5 × 10{sup 3} yr), and likewise compact (R {sub neb} ≲ 0.15 pc), PNe with closed structures and high central electron densities (n{sub e} ≳ 1000 cm{sup –3}), and is rarely associated with PNe that show H{sub 2} emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, two of the five new diffuse X-ray detections (NGC 1501 and NGC 6369) host [WR]-type central stars, supporting the hypothesis that PNe with central stars of [WR]-type are likely to display diffuse X-ray emission.

  18. Atmospheric Modelling for the Removal of Telluric Features from Infrared Planetary Spectra

    CERN Document Server

    Cotton, Daniel V; Kedziora-Chudczer, Lucyna

    2013-01-01

    The effects of telluric absorption on infrared spectra present a problem for the observer. Strong molecular absorptions from species whose concentrations vary with time can be particularly challenging to remove precisely. Yet removing these effects is key to accurately determining the composition of many astronomical objects, planetary atmospheres in particular. Here we present a method for removing telluric effects based on a modelling approach. The method relies only on observations usually made by the planetary astronomer, and so is directly comparable with current techniques. We use the modelling approach to process observations made of Jupiter, and Saturnian moon Titan and compare the results with those of the standard telluric division technique, finding the modelling approach to have distinct advantages even in conditions regarded as ideal for telluric division.

  19. Planetary atmosphere models: A research and instructional web-based resource

    Science.gov (United States)

    Gray, Samuel Augustine

    The effects of altitude change on the temperature, pressure, density, and speed of sound were investigated. These effects have been documented in Global Reference Atmospheric Models (GRAMs) to be used in calculating the conditions in various parts of the atmosphere for several planets. Besides GRAMs, there are several websites that provide online calculators for the 1976 US Standard Atmosphere. This thesis presents the creation of an online calculator of the atmospheres of Earth, Mars, Venus, Titan, and Neptune. The websites consist of input forms for altitude and temperature adjustment followed by a results table for the calculated data. The first phase involved creating a spreadsheet reference based on the 1976 US Standard Atmosphere and other planetary GRAMs available. Microsoft Excel was used to input the equations and make a graphical representation of the temperature, pressure, density, and speed of sound change as altitude changed using equations obtained from the GRAMs. These spreadsheets were used later as a reference for the JavaScript code in both the design and comparison of the data output of the calculators. The websites were created using HTML, CSS, and JavaScript coding languages. The calculators could accurately display the temperature, pressure, density, and speed of sound of these planets from surface values to various stages within the atmosphere. These websites provide a resource for students involved in projects and classes that require knowledge of these changes in these atmospheres. This project also created a chance for new project topics to arise for future students involved in aeronautics and astronautics.

  20. Geochemical and planetary dynamical views on the origin of Earth's atmosphere and oceans

    CERN Document Server

    Dauphas, Nicolas

    2013-01-01

    Earth's volatile elements (H, C, and N) are essential to maintaining habitable conditions for metazoans and simpler life forms. However, identifying the sources (comets, meteorites, and trapped nebular gas) that supplied volatiles to Earth is not straightforward because secondary processes like mantle degassing, crustal recycling, and escape to space modified the composition of the atmosphere. Here, we review two complementary approaches to investigate the origin of Earth's atmosphere and oceans. The geochemical approach uses volatile element abundances and isotopic compositions to identify the possible contributors to the atmosphere and to disentangle the processes that shaped it. In that respect, noble gases (He, Ne, Ar, Kr, and Xe), elements that are chemically inert and possess several isotopes produced by radioactivity, play a critical role. The dynamical approach uses our knowledge of planetary dynamics to track volatile delivery to the Earth, starting with dust transport in the disk to planet-building ...

  1. Ultra-High Resolution Spectroscopic Remote Sensing: A Microscope on Planetary Atmospheres

    Science.gov (United States)

    Kostiuk, Theodor

    2010-01-01

    Remote sensing of planetary atmospheres is not complete without studies of all levels of the atmosphere, including the dense cloudy- and haze filled troposphere, relatively clear and important stratosphere and the upper atmosphere, which are the first levels to experience the effects of solar radiation. High-resolution spectroscopy can provide valuable information on these regions of the atmosphere. Ultra-high spectral resolution studies can directly measure atmospheric winds, composition, temperature and non-thermal phenomena, which describe the physics and chemistry of the atmosphere. Spectroscopy in the middle to long infrared wavelengths can also probe levels where dust of haze limit measurements at shorter wavelength or can provide ambiguous results on atmospheric species abundances or winds. A spectroscopic technique in the middle infrared wavelengths analogous to a radio receiver. infrared heterodyne spectroscopy [1], will be describe and used to illustrate the detailed study of atmospheric phenomena not readily possible with other methods. The heterodyne spectral resolution with resolving power greater than 1,000.000 measures the true line shapes of emission and absorption lines in planetary atmospheres. The information on the region of line formation is contained in the line shapes. The absolute frequency of the lines can be measured to I part in 100 ,000,000 and can be used to accurately measure the Doppler frequency shift of the lines, directly measuring the line-of-sight velocity of the gas to --Im/s precision (winds). The technical and analytical methods developed and used to measure and analyze infrared heterodyne measurements will be described. Examples of studies on Titan, Venus, Mars, Earth, and Jupiter will be presented. 'These include atmospheric dynamics on slowly rotating bodies (Titan [2] and Venus [3] and temperature, composition and chemistry on Mars 141, Venus and Earth. The discovery and studies of unique atmospheric phenomena will also be

  2. The Possible Role of Penning Ionization Processes in Planetary Atmospheres

    Directory of Open Access Journals (Sweden)

    Stefano Falcinelli

    2015-03-01

    Full Text Available In this paper we suggest Penning ionization as an important route of formation for ionic species in upper planetary atmospheres. Our goal is to provide relevant tools to researchers working on kinetic models of atmospheric interest, in order to include Penning ionizations in their calculations as fast processes promoting reactions that cannot be neglected. Ions are extremely important for the transmission of radio and satellite signals, and they govern the chemistry of planetary ionospheres. Molecular ions have also been detected in comet tails. In this paper recent experimental results concerning production of simple ionic species of atmospheric interest are presented and discussed. Such results concern the formation of free ions in collisional ionization of H2O, H2S, and NH3 induced by highly excited species (Penning ionization as metastable noble gas atoms. The effect of Penning ionization still has not been considered in the modeling of terrestrial and extraterrestrial objects so far, even, though metastable helium is formed by radiative recombination of He+ ions with electrons. Because helium is the second most abundant element of the universe, Penning ionization of atomic or molecular species by He*(23S1 is plausibly an active route of ionization in relatively dense environments exposed to cosmic rays.

  3. The o II recombination line abundance problem in planetary nebulae

    Directory of Open Access Journals (Sweden)

    D. R. Garnett

    2001-01-01

    Full Text Available Presentamos observaciones de l neas de recombinaci on de O II en diez nebu- losas planetarias brillantes, y mediciones de O II y [O III] con resoluci on espacial en NGC 6720. Esto es con el n de estudiar la discrepancia entre las abundancias calculadas con l neas de recombinaci on de O II y aquellas derivadas de l neas de excitaci on colisional de [O III]. Observamos una gran variaci on en la discrepan- cia, desde tener resultados consistentes hasta una diferencia de un factor de seis. La magnitud de esta discrepancia esta anti-correlacionada con el brillo super cial de la nebulosa (aquellas que son compactas y m as brillantes tienen las menores variaciones. Los niveles de O II poblados a trav es de recombinaci on di-electr onica dan abundancias mayores que otros niveles. Nuestra observaci on en rendija larga muestra que la emisi on en O II tiene su m aximo al interior de la c ascara brillante donde [O III] y H son m as brillantes. Con base en las correlaciones observadas, proponemos que la intensa emisi on en l neas de recombinaci on en nebulosas plan- etarias proviene de recombinaci on di-electr onica aumentada en el interior de la nebulosa, la cual posiblemente est e impulsada por un viento estelar caliente.

  4. Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures.

    Science.gov (United States)

    Stüeken, E E; Kipp, M A; Koehler, M C; Schwieterman, E W; Johnson, B; Buick, R

    2016-12-01

    Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean-presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere. Key Words: Biosignatures-Early Earth-Planetary atmospheres. Astrobiology 16, 949-963.

  5. Transfer of polarized light in planetary atmospheres basic concepts and practical methods

    CERN Document Server

    Hovenier, Joop W; Domke, Helmut

    2004-01-01

    The principal elements of the theory of polarized light transfer in planetary atmospheres are expounded in a systematic but concise way. Basic concepts and practical methods are emphasized, both for single and multiple scattering of electromagnetic radiation by molecules and particles in the atmospheres of planets in the Solar System, including the Earth, and beyond. A large part of the book is also useful for studies of light scattering by particles in comets, the interplanetary and interstellar medium, circumstellar disks, reflection nebulae, water bodies like oceans and suspensions of particles in a gas or liquid in the laboratory. Throughout the book symmetry principles, such as the reciprocity principle and the mirror symmetry principle, are employed. In this way the theory is made more transparent and easier to understand than in most papers on the subject. In addition, significant computational reductions, resulting from symmetry principles, are presented. Hundreds of references to relevant literature ...

  6. High Temperature, Controlled-Atmosphere Aerodynamic Levitation Experiments with Applications in Planetary Science

    Science.gov (United States)

    Macris, C. A.; Badro, J.; Eiler, J. M.; Stolper, E. M.

    2016-12-01

    The aerodynamic levitation laser apparatus is an instrument in which spherical samples are freely floated on top of a stream of gas while being heated with a CO2laser to temperatures up to about 3500 °C. Laser heated samples, ranging in size from 0.5 to 3.5 mm diameter, can be levitated in a variety of chemically active or inert atmospheres in a gas-mixing chamber (e.g., Hennet et al. 2006; Pack et al. 2010). This allows for containerless, controlled-atmosphere, high temperature experiments with potential for applications in earth and planetary science. A relatively new technique, aerodynamic levitation has been used mostly for studies of the physical properties of liquids at high temperatures (Kohara et al. 2011), crystallization behavior of silicates and oxides (Arai et al. 2004), and to prepare glasses from compositions known to crystallize upon quenching (Tangeman et al. 2001). More recently, however, aerodynamic levitation with laser heating has been used as an experimental technique to simulate planetary processes. Pack et al. (2010) used levitation and melting experiments to simulate chondrule formation by using Ar-H2 as the flow gas, thus imposing a reducing atmosphere, resulting in reduction of FeO, Fe2O3, and NiO to metal alloys. Macris et al. (2015) used laser heating with aerodynamic levitation to reproduce the textures and diffusion profiles of major and minor elements observed in impact ejecta from the Australasian strewn field, by melting a powdered natural tektite mixed with 60-100 μm quartz grains on a flow of pure Ar gas. These experiments resulted in quantitative modeling of Si and Al diffusion, which allowed for interpretations regarding the thermal histories of natural tektites and their interactions with the surrounding impact vapor plume. Future experiments will employ gas mixing (CO, CO2, H2, O, Ar) in a controlled atmosphere levitation chamber to explore the range of fO2applicable to melt-forming impacts on other rocky planetary bodies

  7. Intercomparison of Martian Lower Atmosphere Simulated Using Different Planetary Boundary Layer Parameterization Schemes

    Science.gov (United States)

    Natarajan, Murali; Fairlie, T. Duncan; Dwyer Cianciolo, Alicia; Smith, Michael D.

    2015-01-01

    We use the mesoscale modeling capability of Mars Weather Research and Forecasting (MarsWRF) model to study the sensitivity of the simulated Martian lower atmosphere to differences in the parameterization of the planetary boundary layer (PBL). Characterization of the Martian atmosphere and realistic representation of processes such as mixing of tracers like dust depend on how well the model reproduces the evolution of the PBL structure. MarsWRF is based on the NCAR WRF model and it retains some of the PBL schemes available in the earth version. Published studies have examined the performance of different PBL schemes in NCAR WRF with the help of observations. Currently such assessments are not feasible for Martian atmospheric models due to lack of observations. It is of interest though to study the sensitivity of the model to PBL parameterization. Typically, for standard Martian atmospheric simulations, we have used the Medium Range Forecast (MRF) PBL scheme, which considers a correction term to the vertical gradients to incorporate nonlocal effects. For this study, we have also used two other parameterizations, a non-local closure scheme called Yonsei University (YSU) PBL scheme and a turbulent kinetic energy closure scheme called Mellor- Yamada-Janjic (MYJ) PBL scheme. We will present intercomparisons of the near surface temperature profiles, boundary layer heights, and wind obtained from the different simulations. We plan to use available temperature observations from Mini TES instrument onboard the rovers Spirit and Opportunity in evaluating the model results.

  8. Planetary host stars: Evaluating uncertainties in ultra-cool model atmospheres

    CERN Document Server

    Bozhinova, I; Scholz, A

    2014-01-01

    M-dwarfs are discussed as promising targets for detecting planet at the lower mass end of the planetary mass distribution. An important step in this process is to accurately estimate the stellar parameters of the M-dwarf host star for which the results of stellar model atmosphere simulations are used. We present a comparison of the ATLAS9, MARCS, PHOENIX and Drift-PHOENIX model atmosphere families in the M-dwarf parameter space. We examine the differences in the (T$_{\\rm gas}$, p$_{\\rm gas}$)-structures, in synthetic photometric fluxes and in colour indices. We compiled the broad-band synthetic photometric fluxes for all available M-dwarf model atmospheres for the UKIRT WFCAM ZYJHK, 2MASS JHKs and Johnson UBVRI filters, and calculated related colour indices. We find that the synthetic colours in the IR wavelengths diverge by no more than 0.15 dex amongst all model families. For all bands considered, discrepancies in colour diminish for the higher T$_{\\rm eff}$-end of model atmosphere grids. We notice signific...

  9. Detecting and Constraining N$_2$ Abundances in Planetary Atmospheres Using Collisional Pairs

    CERN Document Server

    Schwieterman, Edward W; Meadows, Victoria S; Misra, Amit; Domagal-Goldman, Shawn

    2015-01-01

    Characterizing the bulk atmosphere of a terrestrial planet is important for determining surface pressure and potential habitability. Molecular nitrogen (N$_2$) constitutes the largest fraction of Earth$'$s atmosphere and is likely to be a major constituent of many terrestrial exoplanet atmospheres. Due to its lack of significant absorption features, N$_2$ is extremely difficult to remotely detect. However, N$_2$ produces an N$_2$-N$_2$ collisional pair, (N$_2$)$_2$, which is spectrally active. Here we report the detection of (N$_2$)$_2$ in Earth$'$s disk-integrated spectrum. By comparing spectra from NASA$'$s EPOXI mission to synthetic spectra from the NASA Astrobiology Institute$'$s Virtual Planetary Laboratory three-dimensional spectral Earth model, we find that (N$_2$)$_2$ absorption produces a ~35$\\%$ decrease in flux at 4.15 $\\mu$m. Quantifying N$_2$ could provide a means of determining bulk atmospheric composition for terrestrial exoplanets and could rule out abiotic O$_2$ generation, which is possible ...

  10. The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres.

    Science.gov (United States)

    Goldblatt, Colin; Watson, Andrew J

    2012-09-13

    The ultimate climate emergency is a 'runaway greenhouse': a hot and water-vapour-rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only after the surface reaches approximately 1400 K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that the Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here, we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon dioxide to the atmosphere. However, our understanding of the dynamics, thermodynamics, radiative transfer and cloud physics of hot and steamy atmospheres is weak. We cannot therefore completely rule out the possibility that human actions might cause a transition, if not to full runaway, then at least to a much warmer climate state than the present one. High climate sensitivity might provide a warning. If we, or more likely our remote descendants, are threatened with a runaway greenhouse, then geoengineering to reflect sunlight might be life's only hope. Injecting reflective aerosols into the stratosphere would be too short-lived, and even sunshades in space might require excessive maintenance. In the distant future, modifying Earth's orbit might provide a sustainable solution. The runaway greenhouse also remains relevant in planetary sciences and astrobiology: as extrasolar planets smaller and nearer to their stars are detected, some will be in

  11. The Dependence of Atmospheric Circulation and Heat Transport on the Planetary Rotation Rate

    Science.gov (United States)

    Basu, S.; Richardson, M. I.; Wilson, R. J.

    2002-12-01

    Simplified models of planetary climate require a parameterization for the equator-to-pole transport of heat and its dependence on factors, including the planetary rotation rate. Various such parameterizations exist, including ones based on the theory of baroclinic eddy mixing, and on principles of global entropy generation. However, such parameterizations are difficult to test given the limited available observational opportunities. In this study, we use a numerical model to examine heat flux dependencies, as part of a wider study of circulation regime sensitivity to rotation rates and other parameters. This study makes use of a simplified version of the Geophysical Fluid Dynamics Laboratory (GFDL) "Skyhi" General Circulation Model (GCM). All terrestrial hydrological processes have been stripped from the model, which in the form used here, is adapted from the Martian version of Skyhi. The atmosphere has the gas properties of CO2, except that it has been made uncondensible. No aerosols or surface ices are allowed. The model surface is flat, and of uniform albedo and thermal inertia. For the simulations presented in this study, the diurnal, seasonal, and eccentricity cycles have been disabled ({ i.e.} the surface and atmosphere receives constant, daily- and seasonally-averaged incident solar radiation). Radiative heating is treated with a band model for CO2 gas in the thermal and near-infrared bands. The use of a complex model to examine simplified theory of heat transport requires some justification since it is not necessarily clear that these models (GCM's) provide an accurate emulation of the real atmosphere (of any given planet). In this study, we have intentionally removed those aspects of GCM's that are of greatest concern. Especially for terrestrial GCM's, the hydrologic cycle is a major source of uncertainty due to radiative feedbacks, and cloud coupling to small-scale, convective mixing. For other planets, aerosols are important as radiatively and dynamical

  12. 3-D model for cosmic ray planetary ionisation in the middle atmosphere

    Directory of Open Access Journals (Sweden)

    P. I. Y. Velinov

    2005-11-01

    Full Text Available A 3-D planetary model of the cosmic ray electron production rate q(h (cm-3 s-1 has been developed for the strato-mesosphere and lower thermosphere (altitude range 30-100 km with a 10-km step. The spectrum of the primary cosmic rays is modelled by an analytical expression using input data from the CREME96 model. An isotropic penetration of the cosmic rays from the upper hemisphere is assumed in the model and a spherical shape of the Earth's atmosphere is taken into account. The longitudinal effect of ionisation from cosmic rays in the mesosphere and lower thermosphere is calculated. A graphical presentation of the computational results is given for 50 and 90 km at 0°, 40°, 50° and 70° N, S latitudes and all longitudes with a step of 30°. The results of this paper provide a basis for a quantitative understanding of the energetic processes of the middle atmosphere and mechanisms affecting the thermodynamical balance of the Earth's atmosphere.

  13. Impact of variations of gravitational acceleration on the general circulation of the planetary atmosphere

    Science.gov (United States)

    Kilic, Cevahir; Raible, Christoph C.; Stocker, Thomas F.; Kirk, Edilbert

    2017-01-01

    Fundamental to the redistribution of energy in a planetary atmosphere is the general circulation and its meridional structure. We use a general circulation model of the atmosphere in an aquaplanet configuration with prescribed sea surface temperature and investigate the influence of the gravitational acceleration g on the structure of the circulation. For g =g0 = 9.81 ms-2 , three meridional cells exist in each hemisphere. Up to about g /g0 = 1.4 all cells increase in strength. Further increasing this ratio results in a weakening of the thermally indirect cell, such that a two- and finally a one-cell structure of the meridional circulation develops in each hemisphere. This transition is explained by the primary driver of the thermally direct Hadley cell: the diabatic heating at the equator which is proportional to g. The analysis of the energetics of the atmospheric circulation based on the Lorenz energy cycle supports this finding. For Earth-like gravitational accelerations transient eddies are primarily responsible for the meridional heat flux. For large gravitational accelerations, the direct zonal mean conversion of energy dominates the meridional heat flux.

  14. Using the transit of Venus to probe the upper planetary atmosphere

    Science.gov (United States)

    Reale, Fabio; Gambino, Angelo F.; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-06-01

    During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultraviolet and soft X-rays with Hinode and Solar Dynamics Observatory missions. We find that, while Venus's optical radius is about 80 km larger than the solid body radius (the top of clouds and haze), the radius increases further by >70 km in the extreme ultraviolet and soft X-rays. This measures the altitude of the densest ion layers of Venus's ionosphere (CO2 and CO), useful for planning missions in situ, and a benchmark case for detecting transits of exoplanets in high-energy bands with future missions, such as the ESA Athena.

  15. Zones, spots, and planetary-scale waves beating in brown dwarf atmospheres

    Science.gov (United States)

    Apai, D.; Karalidi, T.; Marley, M. S.; Yang, H.; Flateau, D.; Metchev, S.; Cowan, N. B.; Buenzli, E.; Burgasser, A. J.; Radigan, J.; Artigau, E.; Lowrance, P.

    2017-08-01

    Brown dwarfs are massive analogs of extrasolar giant planets and may host types of atmospheric circulation not seen in the solar system. We analyzed a long-term Spitzer Space Telescope infrared monitoring campaign of brown dwarfs to constrain cloud cover variations over a total of 192 rotations. The infrared brightness evolution is dominated by beat patterns caused by planetary-scale wave pairs and by a small number of bright spots. The beating waves have similar amplitudes but slightly different apparent periods because of differing velocities or directions. The power spectrum of intermediate-temperature brown dwarfs resembles that of Neptune, indicating the presence of zonal temperature and wind speed variations. Our findings explain three previously puzzling behaviors seen in brown dwarf brightness variations.

  16. Potential Biosignatures in Super-Earth Atmospheres II. Photochemical Responses

    CERN Document Server

    Grenfell, J L; Godolt, M; Palczynski, K; Rauer, H; Stock, J; Paris, P v; Lehmann, R; Selsis, F

    2013-01-01

    Spectral characterization of Super-Earth atmospheres for planets orbiting in the Habitable Zone of M-dwarf stars is a key focus in exoplanet science. A central challenge is to understand and predict the expected spectral signals of atmospheric biosignatures (species associated with life). Our work applies a global-mean radiative-convective-photochemical column model assuming a planet with an Earth-like biomass and planetary development. We investigated planets with gravities of 1g and 3g and a surface pressure of one bar around central stars with spectral classes from M0 to M7. The spectral signals of the calculated planetary scenarios have been presented by Rauer et al. (2011). The main motivation of the present work is to perform a deeper analysis of the chemical processes in the planetary atmospheres. We apply a diagnostic tool, the Pathway Analysis Program, to shed light on the photochemical pathways that form and destroy biosignature species. Ozone is a potential biosignature for complex- life. An import...

  17. Laboratory Measurements and Modeling of Molecular Photoabsorption Cross Sections in the Ultraviolet for Planetary Atmospheres Applications

    Science.gov (United States)

    Stark, Glenn; Smith, P. L.; Lewis, B. R.; Heays, A. N.; Pickering, J.; Blackwell-Whitehead, R.; Blackie, D.

    2008-09-01

    Our research program is dedicated to the measurement and modeling of vacuum ultraviolet and UV molecular photoabsorption cross sections with the highest practical resolution. It supports efforts to interpret and model observations of planetary atmospheres. Measurement and modeling efforts on molecular nitrogen, carbon dioxide, sulfur dioxide, and diatomic sulfur are in progress. N2: We focus on the measurement of line f-values and line widths within the complex spectrum between 80 and 100 nm. Our measurements are incorporated into a theoretical model of the absorption spectrum of N2 which has established the mechanisms responsible for predissociation and reproduces all observed features in 14N2 and its isotopomers as a function of temperature. CO2: The photodissociation of CO2 is a fundamental photochemical process in the atmospheres of Mars and Venus. Our research centers on the measurement of high resolution cross sections from 91 to 120 nm. We have completed measurements at 295 K and 195 K over the 106 to 120 nm region, and we are analyzing recent measurements of cross sections between 91 and 106 nm. SO2: We provide astronomers with high-resolution cross section data for the complex ultraviolet absorption spectrum between 198 and 325 nm. Using the Imperial College VUV Fourier transform spectrometer, we have completed and published room temperature cross sections, and we are completing work on low-temperature measurements over the same spectral region. S2: Interpretations of atmospheric (Io, Jupiter, cometary comae) S2 absorption features are hindered by a complete lack of laboratory cross section data in the ultraviolet. We are beginning an effort to quantify the photoabsorption spectrum of S2 from 200 to 300 nm based on theoretical calculations and laboratory measurements. Coupled-channel calculations will be complemented by measurements of the absorption spectrum of S2 at high resolution.

  18. Helium 584 Å and H Lyman-α Airglow in Giant Planetary Atmospheres: Modeling, Observations, and Implications

    Science.gov (United States)

    Parkinson, Christopher; Esposito, Larry W.

    2016-07-01

    The atmosphere of the outer planets is mainly composed of H2 and neutral atomic helium. The study of He 584 Å and H Lyman-α brightnesses is interesting as the EUV and FUV (Extreme and Far Ultraviolet) planetary airglow have the potential to yield useful information about mixing and other important parameters in their thermospheres. Time variation, asymmetries, and polar enhancement of the airglow are also possible and analysis of the public archived NASA mission data sets (i.e. Voyager and Cassini) can help solve some of the outstanding problems associated with these phenomena. The comparison of observations with results from sophisticated photochemical and radiative transfer models can also help ameliorate unexplained differences in the dynamical processes operating within planetary upper atmospheres. Powerful analysis techniques allow us to extract information on atmospheric mixing, temperatures, and temporal changes due to the solar and seasonal cycles from the variations in distribution and intensity of airglow emissions that result. The presentation will discuss the implications of interpretations from comparison of modeling and observations in giant planetary atmospheres.

  19. Planetary wave signatures in the equatorial atmosphere ionosphere system, and mesosphere- E- and F-region coupling

    Science.gov (United States)

    Abdu, M. A.; Ramkumar, T. K.; Batista, I. S.; Brum, C. G. M.; Takahashi, H.; Reinisch, B. W.; Sobral, J. H. A.

    2006-02-01

    Upward transport of wave energy and momentum due to gravity, tidal and planetary waves from below and extra-tropics controls the phenomenology of the equatorial atmosphere ionosphere system. An important aspect of this phenomenology is the development of small- and large-scale structures including thin layers in the mesosphere and E-region, and the formation of wide spectrum plasma structures of the equatorial F-region, widely known as equatorial spread F/plasma bubble irregularities (that are known to have significant impact on space application systems based on trans-ionospheric radio waves propagation). It seems that the effects of tidal and gravity waves at mesospheric and thermospheric heights and their control of ionospheric densities, electric fields and currents are relatively better known than are the effects originating from vertical coupling due to planetary waves. Results from airglow, radar and ionospheric sounding observations demonstrate the existence of significant planetary wave influence on plasma parameters at E- and F-region heights over equatorial latitudes. We present and discuss here some results showing planetary wave oscillations in concurrent mesospheric winds and equatorial electrojet intensity variations in the Indian sector as well as in the mesospheric airglow and F-layer height variation in Brazil. Also presented are evidences of planetary wave-scale oscillations in equatorial evening pre-reversal electric field (F-region vertical drift) and their effects on equatorial spread F /plasma bubble irregularity development and day-to-day variability.

  20. A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres

    Science.gov (United States)

    Rimmer, P. B.; Helling, Ch

    2016-05-01

    There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic chemistry outside the solar system. We present an ion-neutral chemical network constructed from scratch, Stand2015, that treats hydrogen, nitrogen, carbon, and oxygen chemistry accurately within a temperature range between 100 and 30,000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmospheric chemistry models for HD 209458b, Jupiter, and the present-day Earth using a simple one-dimensional photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting for CO2, H2, CO, and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present. Very little glycine is produced in the absence of any molecular nitrogen and oxygen. This suggests that the production of glycine is inhibited if a gas is too strongly reducing. Possible applications and limitations of the chemical kinetics network are also discussed.

  1. A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres

    CERN Document Server

    Rimmer, Paul B

    2015-01-01

    There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic chemistry outside the solar system. We present an ion-neutral chemical network constructed from scratch, Stand2015, that treats hydrogen, nitrogen, carbon and oxygen chemistry accurately within a temperature range between 100 K and 30000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmospheric chemistry models for HD209458b, Jupiter and the present-day Earth using a simple 1D photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting (1993) for CO2, H2, CO and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The resul...

  2. The Runaway Greenhouse: implications for future climate change, geoengineering and planetary atmospheres

    CERN Document Server

    Goldblatt, Colin

    2012-01-01

    The ultimate climate emergency is a "runaway greenhouse": a hot and water vapour rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only once the surface reaches ~1400K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon diox...

  3. Global Transonic Solutions of Planetary Atmospheres in Hydrodynamic Region $\\mbox{--}$ Hydrodynamic Escape Problem due to Gravity and Heat

    OpenAIRE

    Huang, Bo-Chih; Chou, Shih-Wei; Hong, John M.; Yen, Chien-Chang

    2015-01-01

    The hydrodynamic escape problem (HEP), which is characterized by a free boundary value problem of Euler equation with gravity and heat, is crucial for investigating the evolution of planetary atmospheres. In this paper, the global existence of transonic solutions to the HEP is established using the generalized Glimm method. The new version of Riemann and boundary-Riemann solvers, are provided as building blocks of the generalized Glimm method by inventing the contraction matrices for the homo...

  4. A laboratory investigation of the production and properties of molecular and radical species pertinent to planetary atmospheres

    Science.gov (United States)

    Fahr, Askar; Herron, John; Laufer, Allan H.

    1990-01-01

    Vinylidene (H2C=C) is shown to be the largest photodecomposition channel in the direct photolysis of both C2H2 and C2H4. The chemistry of H2C=C as it relates to planetary atmospheres is discussed. The vinyl radical (C2H3), important in the acetylene chemistry cycle, has been directly observed spectroscopically and the kinetics of several key reactions of this species measured.

  5. A Balloon-Borne Telescope System for Planetary Atmosphere and Plasma Studies

    Science.gov (United States)

    Taguchi, M.; Yoshida, K.; Sakamoto, Y.; Kanazawa, T.; Shoji, Y.; Sawakami, T.; Takahashi, Y.; Hoshino, N.; Sato, T.; Sakanoi, T.

    2007-12-01

    A telescope floating in the polar stratosphere can continuously monitor planets for more than 24 hours. Thin, clear and stable air of the stratosphere makes it possible to observe planets in a condition free from cloud with fine seeing and high atmospheric transmittance. Moreover, a balloon-borne telescope system is less expensive compared with a huge terrestrial telescope or a direct planetary probe mission. Targets of a balloon-borne telescope system will extend over various atmospheric and plasma phenomena on almost all the planets, i.e., a sodium tail of Mercury, lightning, airglow and aurora in the atmospheres of Venus, Jupiter and Saturn, escaping atmospheres of the Earth-type planets, satellite-induced luminous events in the Jovian atmosphere, etc. The first target is global dynamics of the Venusian atmosphere by detecting cloud motion in UV and NIR imagery. A decoupling mechanism and a pair of control moment gyros (CMGs) are mounted at the top of the gondola. The decoupling mechanism isolates the gondola from a balloon and also transfers an excess angular momentum of the CMGs to the balloon. The attitude of the gondola is stabilized at a constant sun azimuthal angle so that a solar cell panel faces to the sun. A 300 mm F30 Schmidt-Cassegrain telescope is installed at the bottom of the gondola. DC/DC converters, a PC, a high voltage power supply for a piezo-electrically moving mirror and digital video recorders are contained in a sealed cell. The azimuthal angle is detected by a sun-sensor. A PC processes sensor output to control DC motors used in the decoupling mechanism and CMGs with an accuracy in azimuthal attitude of about 0.5 deg. The two-axis gimbal mount of the telescope is controlled by the same PC, guiding an object within a field-of-view of a guide telescope. Residual tracking error is detected by a position sensitive photomultiplier tube and corrected by the two-axis moving mirror installed in the optical system. The optical path is divided into

  6. The Atmospheric Lifetime Experiment. II - Calibration

    Science.gov (United States)

    Rasmussen, R. A.; Lovelock, J. E.

    1983-10-01

    The calibration standards used in the Atmospheric Lifetime Experiment (ALE) for CFCl3, CF2Cl2, CH3CCl3, and CCl4 are described. This includes the preparation of the primary standards by static dilution and their propagation and stability for the period 1977-1982. Two independent assessments of the absolute concentrations of the primary standards used to initiate the ALE measurements in 1977-1978 are reported. For consistency in the ALE program the values assigned to the primary standards and subsequent working standards used in the field were not altered during the experiment when results of better estimates of the original concentration values were obtained. Rather, the appropriate factors by which the ALE mixing ratios for a given species should be multiplied to obtain the best estimate of the current concentration of a given species, are provided.

  7. HITRAN2016 : new and improved data and tools towards studies of planetary atmospheres

    Science.gov (United States)

    Gordon, Iouli; Rothman, Laurence S.; Wilzewski, Jonas S.; Kochanov, Roman V.; Hill, Christian; Tan, Yan; Wcislo, Piotr

    2016-10-01

    The HITRAN2016 molecular spectroscopic database is scheduled to be released this year. It will replace the current edition, HITRAN2012 [1], which has been in use, along with some intermediate updates, since 2012.We have added, revised, and improved many transitions and bands of molecular species and their isotopologues. Also, the amount of parameters has also been significantly increased, now incorporating, for instance, broadening by He, H2 and CO2 which are dominant in different planetary atmospheres [2]; non-Voigt line profiles [3]; and other phenomena. This poster will provide a summary of the updates, emphasizing details of some of the most important or drastic improvements or additions.To allow flexible incorporation of the new parameters and improve the efficiency of the database usage, the whole database has been reorganized into a relational database structure and presented to the user by means of a very powerful, easy-to-use internet program called HITRANonline [4] accessible at . This interface allows the user many queries in standard and user-defined formats. In addition, a powerful application called HAPI (HITRAN Application Programing Interface) [5] was developed. HAPI is a set of Python libraries that allows much more functionality for the user. Demonstration of the power of the new tools will also be offered.This work is supported by the NASA PATM (NNX13AI59G), PDART (NNX16AG51G) and AURA (NNX14AI55G) programs.References[1] L.S. Rothman et al, JQSRT 130, 4 (2013)[2] J. S. Wilzewski et al., JQSRT 168, 193 (2016)[3] P. Wcislo et al., JQSRT 177, 75 (2016)[4] C. Hill et al, JQSRT 177, 4 (2016)[5] R.V. Kochanov et al, JQSRT 177, 15 (2016)

  8. Planetary-Scale Wave Structures of the Earth’s Atmosphere Revealed from the COSMIC Observations

    Institute of Scientific and Technical Information of China (English)

    P. S. BRAHMANANDAM; G. UMA; A. Narendra BABU; HUANG Ching-Yuang; G. Anil KUMAR; S. Tulasi RAM; WANG Hsiao-Lan; CHU Yen-Hsyang

    2014-01-01

    GPS radio occultation (GPS RO) method, an active satellite-to-satellite remote sensing technique, is capable of producing accurate, all-weather, round the clock, global refractive index, density, pressure, and temperature profiles of the troposphere and stratosphere. This study presents planetary-scale equatorially trapped Kelvin waves in temperature profiles retrieved using COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites during 2006-2009 and their interactions with background atmospheric conditions. It is found that the Kelvin waves are not only associated with wave periods of higher than 10 days (slow Kelvin waves) with higher zonal wave numbers (either 1 or 2), but also possessing downward phase progression, giving evidence that the source regions of them are located at lower altitudes. A thorough verification of outgoing longwave radiation (OLR) reveals that deep convection activity has developed regularly over the Indonesian region, suggesting that the Kelvin waves are driven by the convective activity. The derived Kelvin waves show enhanced (diminished) tendencies during westward (eastward) phase of the quasi-biennial oscillation (QBO) in zonal winds, implying a mutual relation between both of them. The El Ni˜no and Southern Oscillation (ENSO) below 18 km and the QBO features between 18 and 27 km in temperature profiles are observed during May 2006-May 2010 with the help of an adaptive data analysis technique known as Hilbert Huang Transform (HHT). Further, temperature anomalies computed using COSMIC retrieved temperatures are critically evaluated during different phases of ENSO, which has revealed interesting results and are discussed in light of available literature.

  9. Computing planetary atmospheres with algorithms derived from action thermodynamics and a novel version of the virial theorem for gravitating polyatomic molecules

    CERN Document Server

    Kennedy, Ivan R

    2015-01-01

    An objective revision of the Laplace barometric formula for isothermal planetary atmospheres is proposed. From Clausius virial theorem equating the root mean square kinetic energy to half the gravitational potential energy, planetary atmospheres are required to have declining temperature with altitude as a consequence of the interaction between thermodynamic heat flow and gravity. The virial action hypothesis predicts non adiabatic lapse rates in temperature yielding a practical means to calculate variations with altitude in atmospheric entropy, free energy, molecular density and pressure. Remarkably, the new formulae derived enable prediction of atmospheric profiles with physical properties closely resembling those observed on Earth, Venus and Mars. These new formulae provide an objective basis for computing the dynamic morphology of the atmosphere. Climate scientists may consider this explanatory hypothesis for self organisation of planetary atmospheres for its possible relevance for predicting global surfa...

  10. The aurora as a source of planetary-scale waves in the middle atmosphere. [atmospheric turbulence caused by auroral energy absorption

    Science.gov (United States)

    Chiu, Y. T.; Straus, J. M.

    1974-01-01

    Photographs of global scale auroral forms taken by scanning radiometers onboard weather satellites in 1972 show that auroral bands exhibit well organized wave motion with typical zonal wave number of 5 or so. The scale size of these waves is in agreement with that of well organized neutral wind fields in the 150- to 200-km region during the geomagnetic storm of May 27, 1967. Further, the horizontal scale size revealed by these observations are in agreement with that of high altitude traveling ionospheric disturbances. It is conjectured that the geomagnetic storm is a source of planetary and synoptic scale neutral atmospheric waves in the middle atmosphere. Although there is, at present, no observation of substorm related waves of this scale size at mesospheric and stratospheric altitudes, the possible existence of a new source of waves of the proper scale size to trigger instabilities in middle atmospheric circulation systems may be significant in the study of lower atmospheric response to geomagnetic activity.

  11. Laboratory and theoretical work in the service of planetary atmospheric research

    Science.gov (United States)

    Coustenis, Athena

    2015-08-01

    A large quantity of observations is obtained by instruments onboard space missions exploring our solar system and by large ground-based telescopes observing the planets and also the exoplanets. Spectroscopy plays a major role in this type of investigation. To analyze and exploit these observations, planetary scientists need spectroscopic data covering wide ranges in wavelength but also in temperature, pressure, distance, etc.The outer regions of our solar system in particular, including the giant gaseous planets Jupiter and Saturn and their satellites, have recently been the target of space missions such as Cassini-Huygens and several investigations from the ground. Titan, the largest moon of Saturn, in particular, offers many similarities with our own planet, among which a dense atmosphere whose major component is dinitrogen at about 95%. Combining with methane (at a few percent) and hydrogen, gives rise to a complex organic chemistry with hydrocarbons and nitriles. Oxygen compounds also exist in Titan’s atmosphere. By studying Titan, we learn about our own planet and our Solar system Solar as a whole [1,2,3]. To properly interpret the Cassini-Huygens data and in anticipation of future missions like ESA’s JUICE to the Jupiter system, spectroscopic data are crucially needed. In the field of exoplanets (over 1000 discovered to date), it also becomes urgent to have adequate data of several molecules in order to analyze the observations returned to us every day by major observatories on Earth and in the space [4,5]. I will discuss recent applications from theoretical and experimental studies on the investigation of Titan and exoplanets, with emphasis on methane. I will also present some needs for future analyses.References: [1] Campargue, A., et al. 2012. Icarus 219, 110-128. [2] Coustenis, A., et al. 2013. Astrophys. J. 799, 177, 9p. [3] Hirtzig, et al., 2013. Icarus 226, 470-486 and corrigendum 1182-1182. [4] Tinetti, G., Encrenaz, Th., Coustenis, A., 2013

  12. The Mg II index for upper atmosphere modelling

    Directory of Open Access Journals (Sweden)

    G. Thuillier

    Full Text Available The solar radio flux at 10.7 cm has been used in upper atmosphere density modelling because of its correlation with EUV radiation and its long and complete observational record. A proxy, the Mg II index, for the solar chromospheric activity has been derived by Heath and Schlesinger (1986 from Nimbus-7 data. This index allows one to describe the changes occurring in solar-activity in the UV Sun spectral irradiance. The use of this new proxy in upper atmosphere density modelling will be considered. First, this is supported by the 99.9% correlation between the solar radio flux (F10.7 and the Mg II index over a period of 19 years with, however, large differences on time scales of days to months. Secondly, correlation between EUV emissions and the Mg II index has been shown recently, suggesting that this last index may also be used to describe the EUV variations. Using the same density dataset, a model was first run with the F10.7 index as a solar forcing function and second, with the Mg II index. Comparison of their respective predictions to partial density data showed a 3–8% higher precision when the modelling uses the Mg II index rather than F10.7. An external validation, by means of orbit computation, resulted in a 20–40% smaller RMS of the tracking residuals. A density dataset spanning an entire solar cycle, together with Mg II data, is required to construct an accurate, unbiased as possible density model.

    Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; thermosphere – composition and chemistry – History of geophysics (atmospheric sciences

  13. On the origin of jets and vortices in turbulent planetary atmospheres.

    Science.gov (United States)

    Jougla, Thibault; Dritschel, David G.

    2016-04-01

    Stratified rotating fluids tend to form large scale coherent structures. These structures are present in many different geophysical fluids, for example jet streams in the Earth's atmosphere, the famous and conspicuous jets in the Jovian atmosphere, and oceanic jets like the latent jets and the well-known main currents including the Gulf stream and Kuroshio. Observations, numerical models, and laboratory experiments have sought to explain their origins and their evolutions. To investigate the coexistence, evolution and vertical structure of jets and vortices in turbulent planetary atmospheres, we make use of the widely studied two-layer quasi-geostrophic shallow water model on the β-plane. Numerical simulations at ultra-high resolution are carried out with the Combined Lagrangian Advection Method [1]. Following Panetta 1988 [2], to characterise the pole to equator heating variation on a planet, a vertical shear is imposed and maintained by thermal damping. To crudely represent convection from the bottom layer to the top layer, hetons are constantly added to the flow. Many numerical simulations covering a large range of parameters have been run. The thermal damping and vertical shear dependence has been widely studied and analysed. The baroclinicity of the flow is clearly evident in all cases studied. Moreover, the flow is strongly dependent on thermal damping. There is a competition between baroclinic instabilities trying to reduce the imposed vertical shear and thermal damping trying to maintain the vertical shear. Without any thermal damping, the imposed vertical shear quickly erodes. On the other hand if the thermal damping is very high, the flow is mainly dominated by incoherent, small-scale turbulence. For weaker thermal damping, the competition between baroclinic instability and thermal damping may lead to oscillations between stable and turbulent phases. However, thermal damping does not have a significant impact on the number of homogeneous regions and jets

  14. Analytic evaluation of the weighting functions for remote sensing of blackbody planetary atmospheres : the case of limb viewing geometry

    Science.gov (United States)

    Ustinov, Eugene A.

    2006-01-01

    In a recent publication (Ustinov, 2002), we proposed an analytic approach to evaluation of radiative and geophysical weighting functions for remote sensing of a blackbody planetary atmosphere, based on general linearization approach applied to the case of nadir viewing geometry. In this presentation, the general linearization approach is applied to the limb viewing geometry. The expressions, similar to those obtained in (Ustinov, 2002), are obtained for weighting functions with respect to the distance along the line of sight. Further on, these expressions are converted to the expressions for weighting functions with respect to the vertical coordinate in the atmosphere. Finally, the numerical representation of weighting functions in the form of matrices of partial derivatives of grid limb radiances with respect to the grid values of atmospheric parameters is used for a convolution with the finite field of view of the instrument.

  15. The Chandra Planetary Nebula Survey (ChanPlaNS). II. X-ray Emission from Compact Planetary Nebulae

    CERN Document Server

    Freeman, M; Montez, R; Balick, B; Frew, D J; Jones, D; Miszalski, B; Sahai, R; Blackman, E; Chu, Y -H; De Marco, O; Frank, A; Guerrero, M A; Lopez, J A; Zijlstra, A; Bujarrabal, V; Corradi, R L M; Nordhaus, J; Parker, Q A; Sandin, C; Schönberner, D; Soker, N; Sokoloski, J L; Steffen, M; Toalá, J A; Ueta, T; Villaver, E

    2014-01-01

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (ChanPlaNS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ~1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. ChanPlaNS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. ChanPlaNS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R_neb ~1000 cm^-3), and rarely associated with PNe that show H_2 emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, of the five new diffuse X-ray detections, two host [WR]-type CSPNe, NGC 1501 and NGC 6369, supporting the hypothes...

  16. Developments with the planetWRF and planetMPAS Planetary Atmospheric Models

    Science.gov (United States)

    Richardson, Mark I.; Lee, Christopher; Lian, Yuan; Mischna, Michael A.; Newman, Claire E.; Toigo, Anthony

    2016-10-01

    planetWRF is based upon the NCAR Weather Research and Forecasting (WRF) model and has been applied to Mars, Titan and Pluto. planetWRF offers global-scale, two-way interactive nested mesoscale, and microscale LES simulation of planetary atmospheres using a rectangular grid.Recently, a fully-coupled dust and water cycle aerosol scheme has been introduced based on Morrison and Gettelman [Lee et al., this conference]. The scheme treats both dust and water ice as two-moment distributions. Significantly, the scheme treats all processes (nucleation, growth, advection, sedimentation, radiation) using the two-moment distributions, with no lossy conversion between spectral and radius-bin representation.The LES modeing capability has been augmented with the ability to import HiRISE DTMs to allow simulation of small-scale flow over topography including the first order effects of local slope and shadowing. Simulations of Victoria crater (visited by Opportunity) show dramatic variations of surface temperature on scales of a few meters during the morning and distinct changes in the patterns of wind stress as the crater interior is coupled and decoupled from boundary layer convection at different times. The LES has also been augmented to run with dynamically and radiatively interactive dust.planetMPAS is based upon the NCAR Model for Prediction Across Scales (MPAS), an unstructured mesh model that allows for far more uniform resolution of the whole globe, uses a fully compressible nonhydrostatic dynamical core, and an advanced terrain-following coordinate system. The MPAS model been designed to use WRF physics routines. As such, planetMPAS and planetWRF are alternate dynamical cores within the same modeling system. planetMPAS has major advantages over WRF for certain kinds of global simulations: high-precision tracer problems, e.g. Argon transport on Mars; uniform resolution of polar regions, e.g. water ice cap interactions with the martian global water cycle; and convection

  17. Spectrophotometry near the atmospheric cutoff of the strongest Bowen resonance fluorescence lines of O III in two planetary nebulae

    Science.gov (United States)

    O'Dell, C. R.; Opal, Chet B.

    1989-01-01

    Spectrophotometric results are presented for the stronger, well-resolved Bowen O III resonance fluorescence emission lines in the planetary nebulae 7027 and NGC 7662 down to and including the intrinsically strong line at 3133 A. These data are combined with results from the IUE atlas of spectra and similar results for the longer wavelength lines by Likkel and Aller (1986) to give the first full coverage of the Bowen lines. Good agreement is found with fluorescence theory for the primary cascade lines, except for the Likkel and Aller results. The efficiency of conversion of the exciting He II Ly-alpha into O III lines is determined, and values comparable to other planetary nebulae are found.

  18. Working model of the atmosphere and near planetary space of Jupiter

    Science.gov (United States)

    Moroz, V. I. (Editor)

    1978-01-01

    Basic physical characteristics of Jupiter, its gravitational field, atmosphere, electromagnetic radiation, magnetosphere, meteorite situation and satellites are presented in tables, graphs and figures. Means of observation of the atmosphere and three models of the atmosphere are presented and analyzed.

  19. Galactic cosmic rays on extrasolar Earth-like planets: II. Atmospheric implications

    CERN Document Server

    Grießmeier, J --M; Stadelmann, A; Grenfell, J L; Atri, D

    2016-01-01

    (abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields. As described in the companion article (Paper I), a weak magnetic field results in a high flux of galactic cosmic rays to the top of the planetary atmosphere. We investigate effects that may result from a high flux of galactic cosmic rays both throughout the atmosphere and at the planetary surface. Using an air shower approach, we calculate how the atmospheric chemistry and temperature change under the influence of galactic cosmic rays for Earth-like (N_2-O_2 dominated) atmospheres. We evaluate the production and destruction rate of atmospheric biosignature molecules. We derive planetary emission and transmission spectra to study the influence of galactic cosmic rays on biosignature detectability. We then calculate the resulting surface UV flux, the surface particle flux, and the associated equivalent biological dose rates. We find that up to 20% of stratospheric ozone is destroyed by cosmic-ra...

  20. UV photoabsorption cross sections of CO, N2, and SO2 for studies of the ISM and planetary atmospheres

    Science.gov (United States)

    Smith, Peter L.; Rufus, J.; Yoshino, K.; Parkinson, W. H.; Stark, Glenn; Pickering, Juliet C.; Thorne, A. P.

    2002-01-01

    We report high-resolution laboratory measurements of photoabsorption cross sections of CO, N2, and SO2 in the wavelength range 80 to 320 nm. The motivation is to provide the quantitative data that are needed to analyze observations of absorption by, and to model photochemical processes in, the interstellar medium and a number of planetary atmospheres. Because of the high resolution of the spectrometers used, we can minimize distortion of the spectrum that occurs when instrument widths are greater than the widths of spectral features being measured. In many cases, we can determine oscillator strengths of individual rotational lines - a unique feature of our work.

  1. New Planetary Energy Balance, Ocean-Atmosphere Interaction and their Effects on Extreme Events in North Atlantic

    Science.gov (United States)

    Karrouk, Mohammed-Said

    2016-04-01

    Global warming has now reached the energetic phase of H2O's return to the ground after the saturation of the atmosphere in evaporation since the 80s and 90s of the last century, which were characterized by severe droughts, mainly in Africa. This phase is the result of the accumulation of thermal energy exchanges in the Earth-Ocean-Atmosphere system that resulted in the thrust reversal of the energy balance toward the poles. This situation is characterized by a new thermal distribution: above the ocean, the situation is more in surplus compared to the mainland, or even opposite when the balance is negative on the land, and in the atmosphere, warm thermal advection easily reach the North Pole (planetary crests), as well as cold advection push deep into North Africa and the Gulf of Mexico (planetary valleys). This "New Ground Energy Balance" establishes a "New Meridian Atmospheric Circulation (MAC)" with an undulating character throughout the year, including the winter characterized by intense latitudinal very active energy exchanges between the surplus areas (tropical) and the deficit (polar) on the one hand, and the atmosphere, the ocean and the continent on the other. The excess radiation balance increases the potential evaporation of the atmosphere and provides a new geographical distribution of H2O worldwide: the excess water vapor is easily converted by cold advection (polar vortex) to heavy rains that cause floods or snow storms that paralyze the normal functioning of human activities, which creates many difficulties for users and leaves damage and casualties, but ensures water availability missing since a long time in many parts of the world, in Africa, Europe and America. The new thermal distribution reorganizes the geography of atmospheric pressure: the ocean energy concentration is transmitted directly to the atmosphere, and the excess torque is pushed northward. The Azores anticyclone is strengthened and is a global lock by the Atlantic ridge at Greenland

  2. Transmission spectroscopy of HAT-P-32b with the LBT: confirmation of clouds/hazes in the planetary atmosphere

    CERN Document Server

    Mallonn, Matthias

    2016-01-01

    Spectroscopic observations of a transit event of an extrasolar planet offer the opportunity to study the composition of the planetary atmosphere. We observed a transit of the inflated Hot Jupiter HAT-P-32b with MODS at the LBT to characterize its atmosphere from 3300 to 10000 AA. A time series of target and reference star spectra was binned in two broad-band wavelength channels, from which differential transit light curves were constructed. These broad-band light curves were used to confirm previous transit parameter determinations. To derive the planetary transmission spectrum with a resolution of R ~ 60, we created a chromatic set of 62 narrow-band light curves with an average wavelength width of about 100 AA. The spectrum was corrected for the third-light of a near-by M star, whose spectrum was resolved in the individual exposures. Additionally, we undertook a photometric monitoring campaign of the host star to correct for the influence of starspots. The transmission spectrum of HAT-P-32b shows no pressure...

  3. MASH-II: More Planetary Nebulae from the AAO/UKST H\\alpha Survey

    CERN Document Server

    Miszalski, B; Acker, A; Birkby, J L; Frew, D J; Kovacevic, A

    2007-01-01

    We present a supplement to the Macquarie/AAO/Strasbourg H$\\alpha$ planetary nebulae (PNe) catalogue (MASH), which we denote MASH-II. The supplement consists of over 300 true, likely and possible new Galactic PNe found after re-examination of the entire AAO/UKST H$\\alpha$ survey of the southern Galactic Plane in digital form. We have spectroscopically confirmed over 240 of these new candidates as bona-fide PNe and we include other high quality candidates awaiting spectroscopic confirmation as possible PNe. These latest discoveries largely comprise two distinct groups: small, star-like or moderately resolved PNe at one end and mostly large, extremely low surface brightness PNe at the other. Neither group were easy to discover from simple visual scrutiny of the original survey exposures as for MASH but were relatively straightforward to uncover from the digital images via application of semi-automated discovery techniques. We suspect the few PNe still hidden in the H$\\alpha$ survey will lie outside our search cr...

  4. The Kinematics of the Permitted C ii λ6578 Line in a Large Sample of Planetary Nebulae

    Science.gov (United States)

    Richer, Michael G.; Suárez, Genaro; López, José Alberto; García Díaz, María Teresa

    2017-03-01

    We present spectroscopic observations of the C ii λ6578 permitted line for 83 lines of sight in 76 planetary nebulae at high spectral resolution, most of them obtained with the Manchester Echelle Spectrograph on the 2.1 m telescope at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir. We study the kinematics of the C ii λ6578 permitted line with respect to other permitted and collisionally excited lines. Statistically, we find that the kinematics of the C ii λ6578 line are not those expected if this line arises from the recombination of C2+ ions or the fluorescence of C+ ions in ionization equilibrium in a chemically homogeneous nebular plasma, but instead its kinematics are those appropriate for a volume more internal than expected. The planetary nebulae in this sample have well-defined morphology and are restricted to a limited range in Hα line widths (no large values) compared to their counterparts in the Milky Way bulge; both these features could be interpreted as the result of young nebular shells, an inference that is also supported by nebular modeling. Concerning the long-standing discrepancy between chemical abundances inferred from permitted and collisionally excited emission lines in photoionized nebulae, our results imply that multiple plasma components occur commonly in planetary nebulae.

  5. Efficiency Formulas for the 2K-H Type Planetary Gear Train (A II Type Planetary Gear Train with an Idie Planet Pinion)

    OpenAIRE

    岸, 佐年; 両角, 宗晴

    1989-01-01

    A new 2K-H type planetary gear train with an idle planet pinion is devised. This planetary gear train consists of only spur gears. The function of this planetary gear train is equal to those of the internal 2K-H type planetary gear train and the bevel gear type planetary gear train. The efficiency formulas of this planetary gear train are derived from the theoretical analysis and tabulated. The formulas tabulated can be utilized safely without any understanding of the underlying theory.

  6. Refraction in planetary atmospheres: improved analytical expressions and comparison with a new ray-tracing algorithm

    CERN Document Server

    Betremieux, Yan

    2015-01-01

    Atmospheric refraction affects to various degrees exoplanet transit, lunar eclipse, as well as stellar occultation observations. Exoplanet retrieval algorithms often use analytical expressions for the column abundance along a ray traversing the atmosphere as well as for the deflection of that ray, which are first order approximations valid for low densities in a spherically symmetric homogeneous isothermal atmosphere. We derive new analytical formulae for both of these quantities, which are valid for higher densities, and use them to refine and validate a new ray tracing algorithm which can be used for arbitrary atmospheric temperature-pressure profiles. We illustrate with simple isothermal atmospheric profiles the consequences of our model for different planets: temperate Earth-like and Jovian-like planets, as well as HD189733b, and GJ1214b. We find that, for both hot exoplanets, our treatment of refraction does not make much of a difference to pressures as high as 10 atmosphere, but that it is important to ...

  7. Origin of planetary atmospheres and their role in the evolution of life

    Science.gov (United States)

    Bauer, Siegfried J.

    2002-11-01

    The successful synthesis of amino acids in a reducing gas mixture presumably resembling the primary Earth atmosphere, by the Miller-Urey experiment, had a long lasting influence on the general perception of such an early atmosphere. Based on atmospheric escape, such a reducing atmosphere, however, has a lifetime of only millions of years. According to present view the early atmosphere of Earth may have resulted from mantle degassing of volatiles (H2O, CO2, N2), followed by later accumulation of O2 as product of life (photosynthesis). For Mars, with similar degassing products, evolution of life could have been possible in its early history. Non-reducing atmospheres (with liquid water) although not conductive for local synthesis of prebiotic molecules, may provide a benign environment for the evolution of life via ubiquitous supply of "building blocks" from external sources.

  8. International geophysics series theory of planetary atmospheres an introduction to their physics and chemistry

    CERN Document Server

    Marshall, John

    1978-01-01

    For advanced undergraduate and beginning graduate students in atmospheric, oceanic, and climate science, Atmosphere, Ocean and Climate Dynamics is an introductory textbook on the circulations of the atmosphere and ocean and their interaction, with an emphasis on global scales. It will give students a good grasp of what the atmosphere and oceans look like on the large-scale and why they look that way. The role of the oceans in climate and paleoclimate is also discussed. The combination of observations, theory and accompanying illustrative laboratory experiments sets this text apart by m

  9. Comparative planetary nitrogen atmospheres: Density and thermal structures of Pluto and Triton

    Science.gov (United States)

    Strobel, Darrell F.; Zhu, Xun

    2017-07-01

    Both atmospheres of Pluto and Neptune's largest satellite Triton have cold surfaces with surface gravitational accelerations and atmospheric surface pressures of comparable magnitude. To study their atmospheres we have updated Zhu et al. (2014) model for Pluto's atmosphere by adopting Voigt line profiles in the radiation module with the latest spectral database and extended the model to Triton's atmosphere by including additional parameterized heating due to the magnetospheric electron transport and energy deposition. The CH4 mixing ratio profiles play central roles in differentiating the atmospheres of Pluto and Triton. On Pluto the surface CH4 mole fraction is in the range of 0.3-0.8%, sufficiently high to ensure that it is well mixed in the lower atmosphere and not subject to photochemical destruction. Near the exobase CH4 attains comparable density to N2 due to gravitational diffusive separation and escapes at 500 times the N2 rate (= 1 × 1023 N2 s-1). In Triton's atmosphere, the surface CH4 mole fraction is on the order of 0.015%, sufficiently low to ensure that it is photochemically destroyed irreversibly in the lower atmosphere and that N2 remains the major species, even at the exobase. With solar EUV power only, Triton's upper thermosphere is too cold and magnetospheric heating, approximately comparable to the solar EUV power, is needed to bring the N2 tangential column number density in the 500-800 km range up to values derived from the Voyager 2 UVS observations (Broadfoot et al., 1989). Due to their cold exobase temperatures relative to the gravitational potential energy wells that N2 resides in, atmospheric escape from Triton and Pluto is not dominated by N2 Jeans escape but by CH4 from Pluto and H, C, N and H2 from Triton. The atmospheric thermal structure near the exobase is sensitive to the atmospheric escape rate only when it is significantly greater than 2 × 1027 amu s-1, above which enhanced Jeans escape and larger radial velocity adiabatically

  10. Methods of Celestial Mechanics Volume II: Application to Planetary System, Geodynamics and Satellite Geodesy

    CERN Document Server

    Beutler, Gerhard

    2005-01-01

    G. Beutler's Methods of Celestial Mechanics is a coherent textbook for students as well as an excellent reference for practitioners. Volume II is devoted to the applications and to the presentation of the program system CelestialMechanics. Three major areas of applications are covered: (1) Orbital and rotational motion of extended celestial bodies. The properties of the Earth-Moon system are developed from the simplest case (rigid bodies) to more general cases, including the rotation of an elastic Earth, the rotation of an Earth partly covered by oceans and surrounded by an atmosphere, and the rotation of an Earth composed of a liquid core and a rigid shell (Poincaré model). (2) Artificial Earth Satellites. The oblateness perturbation acting on a satellite and the exploitation of its properties in practice is discussed using simulation methods (CelestialMechanics) and (simplified) first order perturbation methods. The perturbations due to the higher-order terms of the Earth's gravitational potential and reso...

  11. To Cool is to Accrete: Analytic Scalings for Nebular Accretion of Planetary Atmospheres

    CERN Document Server

    Lee, Eve J

    2015-01-01

    Planets acquire atmospheres from their parent circumstellar disks. We derive a general analytic expression for how the atmospheric mass grows with time $t$, as a function of the underlying core mass $M_{\\rm core}$ and nebular conditions, including the gas metallicity $Z$. Planets accrete as much gas as can cool: an atmosphere's doubling time is given by its Kelvin-Helmholtz time. Dusty atmospheres behave differently from atmospheres made dust-free by grain growth and sedimentation. The gas-to-core mass ratio (GCR) of a dusty atmosphere scales as GCR $\\propto t^{0.4} M_{\\rm core}^{1.7} Z^{-0.4} \\mu_{\\rm rcb}^{3.4}$, where $\\mu_{\\rm rcb} \\propto 1/(1-Z)$ (for $Z$ not too close to 1) is the mean molecular weight at the innermost radiative-convective boundary. This scaling applies across all orbital distances and nebular conditions for dusty atmospheres; their radiative-convective boundaries, which regulate cooling, are not set by the external environment, but rather by the internal microphysics of dust sublimati...

  12. Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures

    Science.gov (United States)

    Stüeken, E. E.; Kipp, M. A.; Koehler, M. C.; Schwieterman, E. W.; Johnson, B.; Buick, R.

    2016-12-01

    Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean - presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere.

  13. Mass-independent isotope effects in planetary atmospheres and the early solar system.

    Science.gov (United States)

    Thiemens, M H

    1999-01-15

    A class of isotope effects that alters isotope ratios on a mass-independent basis provides a tool for studying a wide range of processes in atmospheres of Earth and other planets as well as early processes in the solar nebula. The mechanism for the effect remains uncertain. Mass-independent isotopic compositions have been observed in O3, CO2, N2O, and CO in Earth's atmosphere and in carbonate from a martian meteorite, which suggests a role for mass-independent processes in the atmosphere of Mars. Observed mass-independent meteoritic oxygen and sulfur isotopic compositions may derive from chemical processes in the presolar nebula, and their distributions could provide insight into early solar system evolution.

  14. Theory for planetary exospheres: II. Radiation pressure effect on exospheric density profiles

    CERN Document Server

    Beth, Arnaud; Toublanc, Dominique; Dandouras, Iannis; Mazelle, Christian

    2015-01-01

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this second part of our work, we present here the density profiles of atomic Hydrogen in planetary exospheres subject to the radiation pressure. We first provide the altitude profiles of ballistic particles (the dominant exospheric population in most cases), which exhibit strong asymmetries that explain the known geotail phenomenon at Earth. The radiation pressure strongly enhances the densities c...

  15. Zeppelin NT - Measurement Platform for the Exploration of Atmospheric Chemistry and Dynamics in the Planetary Boundary Layer

    Science.gov (United States)

    Hofzumahaus, Andreas; Holland, Frank; Oebel, Andreas; Rohrer, Franz; Mentel, Thomas; Kiendler-Scharr, Astrid; Wahner, Andreas; Brauchle, Artur; Steinlein, Klaus; Gritzbach, Robert

    2014-05-01

    The planetary boundary layer (PBL) is the chemically most active and complex part of the atmosphere where freshly emitted reactive trace gases, tropospheric radicals, atmospheric oxidation products and aerosols exhibit a large variability and spatial gradients. In order to investigate the chemical degradation of trace gases and the formation of secondary pollutants in the PBL, a commercial Zeppelin NT was modified to be used as an airborne measurement platform for chemical and physical observations with high spatial resolution. The Zeppelin NT was developed by Zeppelin Luftschifftechnik (ZLT) and is operated by Deutsche Zeppelin Reederei (DZR) in Friedrichshafen, Germany. The modification was performed in cooperation between Forschungszentrum Jülich and ZLT. The airship has a length of 75 m, can lift about 1 ton of scientific payload and can be manoeuvered with high precision by propeller engines. The modified Zeppelin can carry measurement instruments mounted on a platform on top of the Zeppelin, or inside the gondola beneath the airship. Three different instrument packages were developed to investigate a. gas-phase oxidation processes involving free radicals (OH, HO2) b. formation of secondary organic aerosols (SOA) c. new particle formation (nucleation) The presentation will describe the modified airship and provide an overview of its technical performance. Examples of its application during the recent PEGASOS flight campaigns in Europe will be given.

  16. Low-temperature Kinetic Studies of OH Radical Reactions Relevant to Planetary Atmospheres

    Science.gov (United States)

    Townsend, T. M.; Antiñolo, M.; Ballesteros, B.; Jimenez, E.; Canosa, A.

    2011-05-01

    In the solar system, the temperature (T) of the atmosphere of giant planets or their satellites is only several tens of Kelvin (K). The temperature of the tropopause of Titan (satellite of Saturn) and the surface of Mars is 70 K and 210 K, respectively. In the Earth's atmosphere, T decreases from 298 K (surface) to 210 K close to the T-inversion region (tropopause). The principal oxidants in the Earth's lower atmosphere are ozone, the hydroxyl (OH) radical and hydrogen peroxide. A number of critical atmospheric chemical problems depend on the Earth's oxidising capacity, which is essentially the global burden of these oxidants. In the interstellar clouds and circumstellar envelopes, OH radicals have also been detected. As the chemistry of atmospheres is highly influenced by temperature, the knowledge of the T-dependence of the rate coefficients for OH-reactions (k) is the key to understanding the underlying molecular mechanisms. In general, these reactions take place on a short temporal scale. Therefore, a detection technique with high temporal resolution is required. Measurements of k at low temperatures can be achieved by maintaining a thermalised environment using either cryogenic cooling (T>200 K) or supersonic gas expansion with a Laval nozzle (several tens of K). The pulsed laser photolysis technique coupled with laser induced fluorescence detection has been widely used in our laboratory to determine the rate coefficients of OH-reactions with different volatile organic compounds, such as alcohols (1), saturated and unsaturated aliphatic aldehydes (2), linear ketones (3), as a function of temperature (260 350 K). An experimental system based on the CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique is currently under construction. This technique will allow the performance of kinetic studies of OH-reactions of astrophysical interest at temperatures lower than 200 K.

  17. Theory for planetary exospheres: III. Radiation pressure effect on the Circular Restricted Three Body Problem and its implication on planetary atmospheres

    CERN Document Server

    Beth, Arnaud; Toublanc, Dominique; Dandouras, Iannis; Mazelle, Christian

    2015-01-01

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the stellar radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this third paper, we investigate the effect of the stellar radiation pressure on the Circular Restricted Three Body Problem (CR3BP), called also the photogravitational CR3BP, and its implication on the escape and the stability of planetary exospheres, especially for Hot Jupiters. In particular, we describe the transformation of the equipotentials and the location of the Lagrange points, an...

  18. Parameterization of the Planetary Boundary Layer in Atmospheric General Circulation Models - A Review

    Science.gov (United States)

    1975-03-01

    values of £ and S used by the GFDL and the UK-II GCMs; the formulations have also been used by Estoque & Bhumralkar (1969). Case III. Explicit b.l...of Am. Geophy. Union, 39 (6), 1048-1054. ~42- Estoque , M.A., and C. M. Bhumralkar, 1969: The Flow Over a Localized Heat Source, Mon. Wea. Rev., 97

  19. Pre-conditioned Backward Monte Carlo solutions to radiative transport in planetary atmospheres. Fundamentals: Sampling of propagation directions in polarising media

    CERN Document Server

    Muñoz, García; Mills,; P, F

    2014-01-01

    Context. The interpretation of polarised radiation emerging from a planetary atmosphere must rely on solutions to the vector Radiative Transport Equation (vRTE). Monte Carlo integration of the vRTE is a valuable approach for its flexible treatment of complex viewing and/or illumination geometries and because it can intuitively incorporate elaborate physics. Aims. We present a novel Pre-Conditioned Backward Monte Carlo (PBMC) algorithm for solving the vRTE and apply it to planetary atmospheres irradiated from above. As classical BMC methods, our PBMC algorithm builds the solution by simulating the photon trajectories from the detector towards the radiation source, i.e. in the reverse order of the actual photon displacements. Methods. We show that the neglect of polarisation in the sampling of photon propagation directions in classical BMC algorithms leads to unstable and biased solutions for conservative, optically-thick, strongly-polarising media such as Rayleigh atmospheres. The numerical difficulty is avoid...

  20. The occultation of Mariner 10 by Mercury. [planetary radius and atmospheric radio measurements

    Science.gov (United States)

    Fjeldbo, G.; Kliore, A.; Sweetnam, D.; Esposito, P.; Seidel, B.; Howard, T.

    1976-01-01

    Analysis of Mariner 10 dual-frequency radio-occultation recordings has yielded new information on the radius and atmosphere of Mercury. The ingress measurements, which were conducted near 1.1 deg north latitude and 67.4 deg east longitude on the night side of the planet, gave a value for the radius of 2439.5 + or - 1 km. Egress near 67.6 deg north latitude and 258.4 deg east longitude on the sunlit side yielded a radius of 2439.0 + or - 1 km. The atmospheric measurements showed the electron density to be less than 1000 per cu cm on both sides of the planet. From the latter result one may infer an upper limit to the dayside surface gas density of 1 million molecules per cu cm.

  1. Simulating influence of QBO phase on planetary waves during a stratospheric warming in a general circulation model of the middle atmosphere

    Science.gov (United States)

    Koval, Andrey; Gavrilov, Nikolai; Pogoreltsev, Alexander; Savenkova, Elena

    2016-04-01

    One of the important factors of dynamical interactions between the lower and upper atmosphere is energy and momentum transfer by atmospheric internal gravity waves. For numerical modeling of the general circulation and thermal regime of the middle and upper atmosphere, it is important to take into account accelerations of the mean flow and heating rates produced by dissipating internal waves. The quasi-biennial oscillations (QBOs) of the zonal mean flow at lower latitudes at stratospheric heights can affect the propagation conditions of planetary waves. We perform numerical simulation of global atmospheric circulation for the initial conditions corresponding to the years with westerly and easterly QBO phases. We focus on the changes in amplitudes of stationary planetary waves (SPWs) and traveling normal atmospheric modes (NAMs) in the atmosphere during SSW events for the different QBO phases. For these experiments, we use the global circulation of the middle and upper atmosphere model (MUAM). There is theory of PW waveguide describing atmospheric regions where the background wind and temperature allow the wave propagation. There were introduced the refractive index for PWs and found that strongest planetary wave propagation is in areas of large positive values of this index. Another important PW characteristic is the Eliassen-Palm flux (EP-flux). These characteristics are considered as useful tools for visualizing the PW propagation conditions. Sudden stratospheric warming (SSW) event has significant influence on the formation of the weather anomalous and climate changes in the troposphere. Also, SSW event may affect the dynamical and energy processes in the upper atmosphere. The major SSW events imply significant temperature rises (up to 30 - 40 K) at altitudes 30 - 50 km accompanying with corresponding decreases, or reversals, of climatological eastward zonal winds in the stratosphere.

  2. New planetary atmosphere simulations: application to the organic aerosols of Titan.

    Science.gov (United States)

    Coll, P; Cosia, D; Gazeau, M C; Raulin, F

    1997-01-01

    The atmosphere of Titan partly consists of hazes and aerosol particles. Experimental simulation is one of the powerful approaches to study the processes which yield these particles, and their chemical composition. It provides laboratory analogues, sometimes called tholins. Development and optimization of experimental tools were undertaken in order to perform chemical and physical analyses of analogues under conditions free from contamination. A "Titan aerosol generator" was developed in the frame of the Cassini-Huygens mission, in order to produce Titan's aerosol analogues within conditions closer to those of the titanian atmosphere: cold plasma simulation system, low pressure and low temperature. The direct current (DC) glow discharge is produced by applying a DC voltage between two conductive electrodes inserted into the gas mixture-model of the studied atmosphere- at low pressure. A high-impedance power supply is used to provide the electrical field. All the system is installed in a glove box, which protect samples from any contamination. Finally the research program expected with this new material is presented.

  3. THIS -- next-generation mid-infrared remote sensing of planetary atmospheres using a tuneable heterodyne infrared spectrometer

    Science.gov (United States)

    Sonnabend, G.; Wirtz, D.; Vetterle, V.; Schieder, R.

    2003-12-01

    The Cologne spectrometer THIS (Tuneable Heterodyne Infrared Spectrometer) opens the mid-infrared wavelength region from 8 to 17 microns to ultra-high-resolution spectroscopy. The main scientific goal of THIS is to analyze highly resolved lineshape data of molecules (e.g. O3, NH3, CH4, N2O, HxCy etc.) to deduce physical parameters like wind velocities or height profiles of gases in either the Earth's or other planetary atmospheres. Also astronomical observations of non-solar-system IR-sources like IRC+10216 as well as the measurement of pure rotational transitions of H2 in the interstellar-medium from ground based telescopes are planned in the near future. THIS is a proposed second-generation instrument for the stratospheric observatory SOFIA. With a system noise temperature of less than three times the quantum limit THIS is the first widely tuneable and transportable infrared heterodyne receiver having a sensitivity equivalent to CO2-laser based heterodyne systems. A quantum-cascade-laser is used as local oscillator. Its radiation is superimposed to that from the signal by use of a Fabry-Perot ring-resonator to provide optimum efficiency. The frequency mixing is done by a Mercury-Cadmium-Telluride photomixer and spectral analysis with a resolution of up to 3x107 is performed by means of an Acousto-Optical spectrometer. We report on THIS' successful first observing run performed at the west auxiliary telescope at McMath-Pierce solar observatory on Kitt Peak/Arizona in 11/2002. Very weak non-LTE CO2 emission from the atmosphere of Venus have been observed as well as trace gases in Earth's atmosphere and molecular features in sunspots.

  4. Transmission spectroscopy of HAT-P-32b with the LBT: confirmation of clouds/hazes in the planetary atmosphere

    Science.gov (United States)

    Mallonn, M.; Strassmeier, K. G.

    2016-05-01

    Aims: Spectroscopic observations of a transit event of an extrasolar planet offer the opportunity to study the composition of the planetary atmosphere. This can be done with comparably little telescope time using a low-resolution multi-object spectrograph at a large aperture telescope. We observed a transit of the inflated hot Jupiter HAT-P-32b with the Multi-Object Double Spectrograph at the Large Binocular Telescope to characterize its atmosphere from 3300 to 10 000 Å. Methods: A time series of target and reference star spectra was binned in two broad-band wavelength channels, from which differential transit light curves were constructed. These broad-band light curves were used to confirm previous transit parameter determinations. To derive the planetary transmission spectrum with a resolution of R ~ 60, we created a chromatic set of 62 narrow-band light curves. The spectrum was corrected for the third light of a nearby M star. Additionally, we undertook a photometric monitoring campaign of the host star to correct for the influence of starspots. Results: The transmission spectrum of HAT-P-32b shows no pressure-broadened absorption features from Na and K, which is interpreted by the presence of clouds or hazes in the planetary atmosphere. This result is in agreement with previous studies on the same planet. The presence of TiO in gas phase could be ruled out. We find a 2.8σ indication of increased absorption in the line core of potassium (K I 7699 Å). No narrow absorption features of Na and Hα were detected. Furthermore, tentative indications were found for a slope of increasing opacity toward blue wavelengths from the near-IR to the near-UV with an amplitude of two scale heights. If confirmed by follow-up observations, it can be explained by aerosols either causing Mie scattering or causing Rayleigh scattering with an aerosol - gas scale height ratio below unity. The host star was found to be photometrically stable within the measurement precision. Based on

  5. Collaborative project. Ocean-atmosphere interaction from meso- to planetary-scale. Mechanics, parameterization, and variability

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, Ramalingam [Texas A & M Univ., College Station, TX (United States); Small, Justin [National Center for Atmospheric Research (NCAR), Boulder, CO (United States)

    2015-12-01

    Most climate models are currently run with grid spacings of around 100km, which, with today’s computing power, allows for long (up to 1000 year) simulations, or ensembles of simulations to explore climate change and variability. However this grid spacing does not resolve important components of the weather/climate system such as atmospheric fronts and mesoscale systems, and ocean boundary currents and eddies. The overall aim of this project has been to look at the effect of these small-scale features on the weather/climate system using a suite of high and low resolution climate models, idealized models and observations. High-resolution global coupled integrations using CAM/CESM were carried out at NCAR by the lead PI. At TAMU, we have complemented the work at NCAR by analyzing datasets from the high-resolution (28km) CESM integrations (Small et al., 2014) as well as very high resolution (9km, 3km) runs using a coupled regional climate (CRCM) carried out locally. The main tasks carried out were: 1. Analysis of surface wind in observations and high-resolution CAM/CCSM simulations 2. Development of a feature-tracking algorithm for studying midlatitude air-sea interaction by following oceanic mesoscale eddies and creating composites of the atmospheric response overlying the eddies. 3. Applying the Lagrangian analysis technique in the Gulf Stream region to compare data from observational reanalyses, global CESM coupled simulations, 9km regional coupled simulations and 3km convection-resolving regional coupled simulations. Our main findings are that oceanic mesoscale eddies influence not just the atmospheric boundary layer above them, but also the lower portions of the free troposphere above the boundary layer. Such a vertical response could have implications for a remote influence of Gulf Stream oceanic eddies on North Atlantic weather patterns through modulation of the storm track, similar to what has been noted in the North Pacific. The coarse resolution

  6. Collaborative project. Ocean-atmosphere interaction from meso- to planetary-scale. Mechanics, parameterization, and variability

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, Ramalingam [Texas A & M Univ., College Station, TX (United States); Small, Justin [National Center for Atmospheric Research (NCAR), Boulder, CO (United States)

    2015-12-01

    Most climate models are currently run with grid spacings of around 100km, which, with today’s computing power, allows for long (up to 1000 year) simulations, or ensembles of simulations to explore climate change and variability. However this grid spacing does not resolve important components of the weather/climate system such as atmospheric fronts and mesoscale systems, and ocean boundary currents and eddies. The overall aim of this project has been to look at the effect of these small-scale features on the weather/climate system using a suite of high and low resolution climate models, idealized models and observations. High-resolution global coupled integrations using CAM/CESM were carried out at NCAR by the lead PI. At TAMU, we have complemented the work at NCAR by analyzing datasets from the high-resolution (28km) CESM integrations (Small et al., 2014) as well as very high resolution (9km, 3km) runs using a coupled regional climate (CRCM) carried out locally. The main tasks carried out were: 1. Analysis of surface wind in observations and high-resolution CAM/CCSM simulations 2. Development of a feature-tracking algorithm for studying midlatitude air-sea interaction by following oceanic mesoscale eddies and creating composites of the atmospheric response overlying the eddies. 3. Applying the Lagrangian analysis technique in the Gulf Stream region to compare data from observational reanalyses, global CESM coupled simulations, 9km regional coupled simulations and 3km convection-resolving regional coupled simulations. Our main findings are that oceanic mesoscale eddies influence not just the atmospheric boundary layer above them, but also the lower portions of the free troposphere above the boundary layer. Such a vertical response could have implications for a remote influence of Gulf Stream oceanic eddies on North Atlantic weather patterns through modulation of the storm track, similar to what has been noted in the North Pacific. The coarse resolution

  7. Using the transit of Venus to probe the upper planetary atmosphere

    CERN Document Server

    Reale, Fabio; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-01-01

    The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus during the transit in three different bands with subpixel accuracy: optical (4500A), UV (1600A, 1700A), Extreme UltraViolet (EUV, 171-335A) and soft X-rays (about 10A). We find that, while the Venus optical radius is about 80 km larger than the solid body radius (the expected opacity mainly due to clouds and haze), the radius i...

  8. Evolution of Earth-like Extrasolar Planetary Atmospheres: Assessing the Atmospheres and Biospheres of Early Earth Analog Planets with a Coupled Atmosphere Biogeochemical Model

    Science.gov (United States)

    Gebauer, S.; Grenfell, J. L.; Stock, J. W.; Lehmann, R.; Godolt, M.; von Paris, P.; Rauer, H.

    2017-01-01

    Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models. In this work, we present results from our newly developed Coupled Atmosphere Biogeochemistry model in which atmospheric O2 concentrations are fixed to values inferred by geological evidence. Applying a unique tool (Pathway Analysis Program), ours is the first quantitative analysis of catalytic cycles that governed O2 in early Earth's atmosphere near the Great Oxidation Event. Complicated oxidation pathways play a key role in destroying O2, whereas in the upper atmosphere, most O2 is formed abiotically via CO2 photolysis. The O2 bistability found by Goldblatt et al. (2006) is not observed in our calculations likely due to our detailed CH4 oxidation scheme. We calculate increased CH4 with increasing O2 during the Great Oxidation Event. For a given atmospheric surface flux, different atmospheric states are possible; however, the net primary productivity of the biosphere that produces O2 is unique. Mixing, CH4 fluxes, ocean solubility, and mantle/crust properties strongly affect net primary productivity and surface O2 fluxes. Regarding exoplanets, different "states" of O2 could exist for similar biomass output. Strong geological activity could lead to false negatives for life (since our analysis suggests that reducing gases remove O2 that

  9. Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data

    CERN Document Server

    Borucki, William J; Basri, Gibor; Batalha, Natalie; Brown, Timothy M; Bryson, Stephen T; Caldwell, Douglas; Christensen-Dalsgaard, Jørgen; Cochran, William D; DeVore, Edna; Dunham, Edward W; Gautier, Thomas N; Geary, John C; Gilliland, Ronald; Gould, Alan; Howell, Steve B; Jenkins, Jon M; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Rowe, Jason; Sasselov, Dimitar; Boss, Alan; Charbonneau, David; Ciardi, David; Doyle, Laurance; Dupree, Andrea K; Ford, Eric B; Fortney, Jonathan; Holman, Matthew J; Seager, Sara; Steffen, Jason H; Tarter, Jill; Welsh, William F; Allen, Christopher; Buchhave, Lars A; Christiansen, Jessie L; Clarke, Bruce D; Désert, Jean-Michel; Endl, Michael; Fabrycky, Daniel; Fressin, Francois; Haas, Michael; Horch, Elliott; Howard, Andrew; Isaacson, Howard; Kjeldsen, Hans; Kolodziejczak, Jeffery; Kulesa, Craig; Li, Jie; Machalek, Pavel; McCarthy, Donald; MacQueen, Phillip; Meibom, Søren; Miquel, Thibaut; Prsa, Andrej; Quinn, Samuel N; Quintana, Elisa V; Ragozzine, Darin; Sherry, William; Shporer, Avi; Tenenbaum, Peter; Torres, Guillermo; Twicken, Joseph D; Van Cleve, Jeffrey; Walkowicz, Lucianne

    2011-01-01

    On 1 February 2011 the Kepler Mission released data for 156,453 stars observed from the beginning of the science observations on 2 May through 16 September 2009. There are 1235 planetary candidates with transit like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class-sizes; 68 candidates of approximately Earth-size (radius < 1.25 Earth radii), 288 super-Earth size (1.25 Earth radii < radius < 2 Earth radii), 662 Neptune-size (2 Earth radii < radius < 6 Earth radii), 165 Jupiter-size (6 Earth radii < radius < 15 Earth radii), and 19 up to twice the size of Jupiter (15 Earth radii < radius < 22 Earth radii). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Five are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune....

  10. Theory for planetary exospheres: II. Radiation pressure effect on exospheric density profiles

    Science.gov (United States)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Mazelle, C.

    2016-03-01

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this second part of our work, we present here the density profiles of atomic Hydrogen in planetary exospheres subject to the radiation pressure. We first provide the altitude profiles of ballistic particles (the dominant exospheric population in most cases), which exhibit strong asymmetries that explain the known geotail phenomenon at Earth. The radiation pressure strongly enhances the densities compared with the pure gravity case (i.e. the Chamberlain profiles), in particular at noon and midnight. We finally show the existence of an exopause that appears naturally as the external limit for bounded particles, above which all particles are escaping.

  11. THOR: A New and Flexible Global Circulation Model to Explore Planetary Atmospheres

    CERN Document Server

    Mendonça, João M; Grosheintz, Luc; Heng, Kevin

    2016-01-01

    We have designed and developed, from scratch, a global circulation model named THOR that solves the three-dimensional non-hydrostatic Euler equations. Our general approach lifts the commonly used assumptions of a shallow atmosphere and hydrostatic equilibrium. We solve the "pole problem" (where converging meridians on a sphere lead to increasingly smaller time steps near the poles) by implementing an icosahedral grid. Irregularities in the grid, which lead to grid imprinting, are smoothed using the "spring dynamics" technique. We validate our implementation of spring dynamics by examining calculations of the divergence and gradient of test functions. To prevent the computational time step from being bottlenecked by having to resolve sound waves, we implement a split-explicit method together with a horizontally explicit and vertically implicit integration. We validate our global circulation model by reproducing the Earth and also the hot Jupiter-like benchmark tests. THOR was designed to run on Graphics Proces...

  12. Laboratory measurements and modeling of molecular photoabsorption in the ultraviolet for planetary atmospheres applications: diatomic sulfur and sulfur monoxide

    Science.gov (United States)

    Stark, Glenn

    2016-07-01

    Our research program comprises the measurement and modeling of ultraviolet molecular photoabsorption cross sections with the highest practical resolution. It supports efforts to interpret and model observations of planetary atmospheres. Measurement and modeling efforts on diatomic sulfur (S _{2}) and sulfur monoxide (SO) are in progress. S _{2}: Interpretations of atmospheric (Io, Jupiter, cometary comae) S _{2} absorption features are hindered by a complete lack of laboratory cross section data in the ultraviolet. We are working to quantify the photoabsorption spectrum of S _{2} from 240 to 300 nm based on laboratory measurements and theoretical calculations. We have constructed an experimental apparatus to produce a stable column of S _{2} vapor at a temperature of 800 K. High-resolution measurements of the absorption spectrum of the strong B - X system of S _{2} were completed using the NIST VUV-FTS at Gaithersburg, Maryland. These measurements are currently being incorporated into a coupled-channel model of the absorption spectrum of S _{2} to quantify the contributions from individual band features and to establish the mechanisms responsible for the strong predissociation signature of the B - X system. A successful coupled channels model can then be used to calculate the B - X absorption spectrum at any temperature. SO: There has been a long-standing need for high-resolution cross sections of sulfur monoxide radicals in the ultraviolet and vacuum ultraviolet regions, where the molecule strongly predissociates, for modeling the atmospheres of Io and Venus, and most recently for understanding sulfur isotope effects in the ancient (pre-O _{2}) atmosphere of Earth. We have produced a measurable column of SO in a continuous-flow DC discharge cell, using SO _{2} as a parent molecule. Photoabsorption measurements were recently recorded on the DESIRS beamline of the SOLEIL synchrotron, taking advantage of the high-resolution VUV-FTS on that beamline. A number of

  13. Characteristics of mid-latitude planetary waves in the lower atmosphere derived from radiosonde data

    Directory of Open Access Journals (Sweden)

    R. Wang

    2012-10-01

    Full Text Available The activities of mid-latitude planetary waves (PWs in the troposphere and lower stratosphere (TLS are presented by using the radiosonde data from 2000 to 2004 over four American stations (Miramar Nas, 32.9° N, 117.2° W; Santa Teresa, 31.9° N, 106.7° W; Fort Worth, 32.8° N, 97.3° W; and Birmingham, 33.1° N, 86.7° W and one Chinese station (Wuhan, 30.5° N, 114.4° E. Statistically, strong PWs mainly appear around subtropical jet stream in the troposphere and lower stratosphere. In the troposphere, the activities of the mid-latitude PWs are strong around the centre of the subtropical jet stream in winter and become small near the tropopause, which indicates that the subtropical jet stream may strengthen the propagation of PWs or even be one of the PW excitation sources. Among the three disturbance components of temperature, zonal and meridional winds, PWs at Wuhan are stronger in the temperature component, but weaker in the zonal wind component than at the other four American stations. While in the meridional wind component, the strengths of PW spectral amplitudes at the four American stations decrease from west to east, and their amplitudes are all larger than that of Wuhan. However, the PWs are much weaker in the stratosphere and only the lower frequency parts remain. The amplitudes of the PWs in the stratosphere increase with height and are strong in winter with the zonal wind component being the strongest. Using the refractive index, we found that whether the PWs could propagate upward to the stratosphere depends on the thickness of the tropopause reflection layer. In the case study of the 2000/2001 winter, it is observed that the quasi 16-day wave in the troposphere is a quasi standing wave in the vertical direction and propagates upward slowly with vertical wavelength greater than 24 km in the meridional component. It propagates eastward with the zonal numbers between 5 and 8, and the quasi 16-day wave at Wuhan is probably the same

  14. Planetcam: A Visible And Near Infrared Lucky-imaging Camera To Study Planetary Atmospheres And Solar System Objects

    Science.gov (United States)

    Sanchez-Lavega, Agustin; Rojas, J.; Hueso, R.; Perez-Hoyos, S.; de Bilbao, L.; Murga, G.; Ariño, J.; Mendikoa, I.

    2012-10-01

    PlanetCam is a two-channel fast-acquisition and low-noise camera designed for a multispectral study of the atmospheres of the planets (Venus, Mars, Jupiter, Saturn, Uranus and Neptune) and the satellite Titan at high temporal and spatial resolutions simultaneously invisible (0.4-1 μm) and NIR (1-2.5 μm) channels. This is accomplished by means of a dichroic beam splitter that separates both beams directing them into two different detectors. Each detector has filter wheels corresponding to the characteristic absorption bands of each planetary atmosphere. Images are acquired and processed using the “lucky imaging” technique in which several thousand images of the same object are obtained in a short time interval, coregistered and ordered in terms of image quality to reconstruct a high-resolution ideally diffraction limited image of the object. Those images will be also calibrated in terms of intensity and absolute reflectivity. The camera will be tested at the 50.2 cm telescope of the Aula EspaZio Gela (Bilbao) and then commissioned at the 1.05 m at Pic-duMidi Observatory (Franca) and at the 1.23 m telescope at Calar Alto Observatory in Spain. Among the initially planned research targets are: (1) The vertical structure of the clouds and hazes in the planets and their scales of variability; (2) The meteorology, dynamics and global winds and their scales of variability in the planets. PlanetCam is also expected to perform studies of other Solar System and astrophysical objects. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

  15. Planetary wave coupling processes in the middle atmosphere (30 90 km): A study involving MetO and MFR data

    Science.gov (United States)

    Chshyolkova, T.; Manson, A. H.; Meek, C. E.; Avery, S. K.; Thorsen, D.; MacDougall, J. W.; Hocking, W.; Murayama, Y.; Igarashi, K.

    2006-02-01

    The MetO assimilated data and mesospheric winds provided by five medium frequency radars (MFR) from the Canada US Japan Opportunity (CUJO) network have been used to study coupling processes due to planetary waves (PWs) in the middle atmosphere. It is shown that there is strong vertical coupling between the stratosphere and mesosphere especially during winter months. However, not all observed disturbances in mesospheric winds can be explained by the simple propagation of PWs from below. In addition to the vertical coupling there is also weaker horizontal “inter-hemispheric” coupling during equinoxes. The data used are from December 2000 to December 2002. The time interval was chosen to include austral winters and springs of 2 years: the dynamically unusual year 2002, during which a major stratospheric warming involving a split vortex and wind reversals occurred in the Southern Hemisphere, and a more typical year 2001. The character of PW activity during these 2 years is compared. In contrast to the usually weak PW activity dominated by eastward motions, both strong eastward and westward propagating waves existed during austral winter of 2002. Wavelet spectra of MetO winds show strong peaks near 14 days that match similar signals observed in mesospheric winds at Antarctic stations [Dowdy et al., 2004. The large-scale dynamics of the mesosphere lower thermosphere during the SH stratospheric warming of 2002. Geophysical Research Letters 31, L14102. doi:10.1029/2004GL020282] during the stratospheric warming. It is suggested that this oscillation was generated at low atmospheric heights and propagated upward. The longer duration of the stratospheric mesospheric winter vortex (7 months) compared to that of the summer jet in the Northern Hemisphere provide equinoctial months when eastward winds dominate globally. Results suggest that during equinoxes, with favourable conditions, the PWs with ˜10-, 16- and 25-day periods can penetrate to the opposite hemisphere.

  16. Collaborative project. Ocean-atmosphere interaction from meso-to planetary-scale. Mechanisms, parameterization, and variability

    Energy Technology Data Exchange (ETDEWEB)

    Small, Richard [National Center for Atmospheric Research, Boulder, CO (United States); Bryan, Frank [National Center for Atmospheric Research, Boulder, CO (United States); Tribbia, Joseph [National Center for Atmospheric Research, Boulder, CO (United States); Park, Sungsu [National Center for Atmospheric Research, Boulder, CO (United States); Dennis, John [National Center for Atmospheric Research, Boulder, CO (United States); Saravanan, R. [National Center for Atmospheric Research, Boulder, CO (United States); Schneider, Niklas [National Center for Atmospheric Research, Boulder, CO (United States); Kwon, Young-Oh [National Center for Atmospheric Research, Boulder, CO (United States)

    2015-06-11

    This project aims to improve long term global climate simulations by resolving ocean mesoscale activity and the corresponding response in the atmosphere. The main computational objectives are; i) to perform and assess Community Earth System Model (CESM) simulations with the new Community Atmospheric Model (CAM) spectral element dynamical core; ii) use static mesh refinement to focus on oceanic fronts; iii) develop a new Earth System Modeling tool to investigate the atmospheric response to fronts by selectively filtering surface flux fields in the CESM coupler. The climate research objectives are 1) to improve the coupling of ocean fronts and the atmospheric boundary layer via investigations of dependency on model resolution and stability functions: 2) to understand and simulate the ensuing tropospheric response that has recently been documented in observations: and 3) to investigate the relationship of ocean frontal variability to low frequency climate variability and the accompanying storm tracks and extremes in high resolution simulations. This is a collaborative multi-institution project consisting of computational scientists, climate scientists and climate model developers. It specifically aims at DOE objectives of advancing simulation and predictive capability of climate models through improvements in resolution and physical process representation.

  17. Venus as a laboratory for studying planetary surface, interior, and atmospheric evolution

    Science.gov (United States)

    Smrekar, S. E.; Hensley, S.; Helbert, J.

    2013-12-01

    As Earth's twin, Venus offers a laboratory for understanding what makes our home planet unique in our solar system. The Decadal Survey points to the role of Venus in answering questions such as the supply of water and its role in atmospheric evolution, its availability to support life, and the role of geology and dynamics in controlling volatiles and climate. On Earth, the mechanism of plate tectonics drives the deformation and volcanism that allows volatiles to escape from the interior to the atmosphere and be recycled into the interior. Magellan revealed that Venus lacks plate tectonics. The number and distribution of impact craters lead to the idea Venus resurfaced very rapidly, and inspired numerous models of lithospheric foundering and episodic plate tectonics. However we have no evidence that Venus ever experienced a plate tectonic regime. How is surface deformation affected if no volatiles are recycled into the interior? Although Venus is considered a ';stagnant' lid planet (lacking plate motion) today, we have evidence for recent volcanism. The VIRTIS instrument on Venus Express mapped the southern hemisphere at 1.02 microns, revealing areas likely to be unweathered, recent volcanic flows. Additionally, numerous studies have shown that the crater population is consistent with ongoing, regional resurfacing. How does deformation and volcanism occur in the absence of plates? At what rate is the planet resurfacing and thus outgassing? Does lithospheric recycling occur with plate tectonics? In the 25 years since Magellan, the design of Synthetic Aperture Radar has advanced tremendously, allowing order of magnitude improvements in altimetry and imaging. With these advanced tools, we can explore Venus' past and current tectonic states. Tesserae are highly deformed plateaus, thought to be possible remnants of Venus' earlier tectonic state. How did they form? Are they low in silica, like Earth's continents, indicating the presence of abundant water? Does the plains

  18. Evolution of Earth-like Extrasolar Planetary Atmospheres: Assessing the Atmospheres and Biospheres of Early Earth Analog Planets with a Coupled Atmosphere Biogeochemical Model.

    Science.gov (United States)

    Gebauer, S; Grenfell, J L; Stock, J W; Lehmann, R; Godolt, M; von Paris, P; Rauer, H

    2017-01-01

    Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models. In this work, we present results from our newly developed Coupled Atmosphere Biogeochemistry model in which atmospheric O2 concentrations are fixed to values inferred by geological evidence. Applying a unique tool (Pathway Analysis Program), ours is the first quantitative analysis of catalytic cycles that governed O2 in early Earth's atmosphere near the Great Oxidation Event. Complicated oxidation pathways play a key role in destroying O2, whereas in the upper atmosphere, most O2 is formed abiotically via CO2 photolysis. The O2 bistability found by Goldblatt et al. ( 2006 ) is not observed in our calculations likely due to our detailed CH4 oxidation scheme. We calculate increased CH4 with increasing O2 during the Great Oxidation Event. For a given atmospheric surface flux, different atmospheric states are possible; however, the net primary productivity of the biosphere that produces O2 is unique. Mixing, CH4 fluxes, ocean solubility, and mantle/crust properties strongly affect net primary productivity and surface O2 fluxes. Regarding exoplanets, different "states" of O2 could exist for similar biomass output. Strong geological activity could lead to false negatives for life (since our analysis suggests that reducing gases remove O2 that

  19. THOR: A New and Flexible Global Circulation Model to Explore Planetary Atmospheres

    Science.gov (United States)

    Mendonça, João M.; Grimm, Simon L.; Grosheintz, Luc; Heng, Kevin

    2016-10-01

    We have designed and developed, from scratch, a global circulation model (GCM) named THOR that solves the three-dimensional nonhydrostatic Euler equations. Our general approach lifts the commonly used assumptions of a shallow atmosphere and hydrostatic equilibrium. We solve the “pole problem” (where converging meridians on a sphere lead to increasingly smaller time steps near the poles) by implementing an icosahedral grid. Irregularities in the grid, which lead to grid imprinting, are smoothed using the “spring dynamics” technique. We validate our implementation of spring dynamics by examining calculations of the divergence and gradient of test functions. To prevent the computational time step from being bottlenecked by having to resolve sound waves, we implement a split-explicit method together with a horizontally explicit and vertically implicit integration. We validate our GCM by reproducing the Earth and hot-Jupiter-like benchmark tests. THOR was designed to run on graphics processing units (GPUs), which allows for physics modules (radiative transfer, clouds, chemistry) to be added in the future, and is part of the open-source Exoclimes Simulation Platform (www.exoclime.org).

  20. Theory for planetary exospheres: III. Radiation pressure effect on the Circular Restricted Three Body Problem and its implication on planetary atmospheres

    Science.gov (United States)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Mazelle, C.

    2016-12-01

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the stellar radiation pressure on planetary exospheres. In a series of papers, we present with a Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain [1989] Icarus, 81, 145-163. In this third paper, we investigate the effect of the stellar radiation pressure on the Circular Restricted Three Body Problem (CR3BP), called also the photogravitational CR3BP, and its implication on the escape and the stability of planetary exospheres, especially for hot Jupiters. In particular, we describe the transformation of the equipotentials and the location of the Lagrange points, and we provide a modified equation for the Hill sphere radius that includes the influence of the radiation pressure. Finally, an application to the hot Jupiter HD 209458b and hot Neptune GJ 436b reveals the existence of a blow-off escape regime induced by the stellar radiation pressure.

  1. Insights into Planet Formation from Debris Disks. II. Giant Impacts in Extrasolar Planetary Systems

    Science.gov (United States)

    Wyatt, Mark C.; Jackson, Alan P.

    2016-12-01

    Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10 Myr post-impact, but model uncertainties could reduce detectability to a few 100 yr window. Nevertheless the 3 % of young stars with debris at levels expected during terrestrial planet formation provide valuable constraints on formation models; implications for super-Earth formation are also discussed. Variability recently observed in some bright disks promises to illuminate the evolution during the earliest phases when vapour condensates may be optically thick and acutely affected by the collision-point geometry. The outer reaches of planetary systems may also exhibit signatures of giant impacts, such as the clumpy debris structures seen around some stars.

  2. Planetary perturbations for Oort cloud comets: II. Implications for the origin of observable comets

    Science.gov (United States)

    Fouchard, M.; Rickman, H.; Froeschlé, Ch.; Valsecchi, G. B.

    2014-03-01

    We present Monte Carlo simulations of the dynamical history of the Oort cloud, where in addition to the main external perturbers (Galactic tides and stellar encounters) we include, as done in a companion paper (Fouchard, M., Rickman, H., Froeschlé, Ch., Valsecchi, G.B. [2013b]. Icarus, in press), the planetary perturbations experienced each time the comets penetrate to within 50 AU of the Sun. Each simulation involves an initial sample of four million comets and extends over a maximum of 5 Gyr. For better understanding of the outcomes, we supplement the full dynamical model by others, where one or more of the effects are left out. We concentrate on the production of observable comets, reaching for the first time a perihelion within 5 AU of the Sun. We distinguish between four categories, depending on whether the comet jumps across, or creeps through, the Jupiter-Saturn barrier (perihelion distances between 5 and 15 AU), and whether the orbit leading to the observable perihelion is preceded by a major planetary perturbation or not. For reasons explained in the paper, we call the strongly perturbed comets "Kaib-Quinn comets". We thus derive a synthetic picture of the Oort spike, from which we draw two main conclusions regarding the full dynamical model. One is that 2/3 of the observable comets are injected with the aid of a planetary perturbation at the previous perihelion passage, and about half of the observable comets are of the Kaib-Quinn type. The other is that the creepers dominate over the jumpers. Due to this fact, the spike peaks at only 31 000 AU, and the majority of new comets have semi-major axes less than this value. The creepers show a clear preference for retrograde orbits as a consequence of the need to avoid untimely, planetary ejection before becoming observable. Thus, the new comets should have a 60/40 preference for retrograde against prograde orbits in apparent conflict with observations. However, both these and other results depend on our model

  3. Effects of the planetary-scale waves on the temporal variations of the O2-1.27μm nightglow in the Venusian upper atmosphere

    Science.gov (United States)

    Hoshino, N.; Fujiwara, H.; Takagi, M.; Kasaba, Y.; Takahashi, Y.

    2009-12-01

    The O2-1.27 μm nightglow distribution, which has the peak intensity in the depression region of the day-to-night flow, gives us information of the wind field at about 95 km in Venus. The past nightglow observations [Crisp et al., 1996] showed that the intensity of the nightglow in the brightness region changed by 20 % in about one hour, and the brightness region disappeared in less than one day. The observation results obtained by Venus Express (VEX) also showed the temporal variations of the nightglow emission. Some simulation studies suggested contributions of gravity waves generated in the cloud deck (50-70 km) to the temporal variations. However, the causes of the temporal variations are still unknown. In recent years, the importance of planetary-scale waves for the dynamics of the Venusian atmosphere has been recognized. For example, Takagi and Matsuda [2006] suggested that the atmospheric superrotation was driven by the momentum transport due to the vertical propagation of the thermal tides generated in the Venus cloud deck. In order to estimate effects of the planetary-scale waves on the temporal variations of the nightglow, we have performed numerical simulations with a general circulation model (GCM), which includes the altitude region of 80 - about 200 km. The planetary-scale waves (thermal tides, Kelvin wave and Rosbby wave) are imposed at the lower boundary. The amplitudes and phase velocities of the waves are assumed from the study by Del Genio and Rossow [1990]. The nightglow intensity and its global distribution are calculated from the GCM results assuming the chemical equilibration. In this study, we investigate contributions of the planetary-scale waves on the temporal variations of the nightglow shown by past observations. In addition, we show the characteristics of the wave propagation and the interactions between the waves in the Venusian upper atmosphere. Venus Climate Orbiter (VCO), which will be launched in 2010 as the second Japanese

  4. Insights into planet formation from debris disks: II. Giant impacts in extrasolar planetary systems

    CERN Document Server

    Wyatt, Mark C

    2016-01-01

    Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10Myr post-impac...

  5. Amateur - professional collaborations in Giant Planets Atmospheres Research through the Planetary Virtual Observatory of the International Outer Planets Watch (PVOL - IOPW)

    Science.gov (United States)

    Hueso, R.; Legarreta, J.; Sánchez-Lavega, A.

    2015-10-01

    The atmospheres node of the International Outer Planets Watch (IOPW) maintains a large database of observations of the Giant Planets called Planetary Virtual Observatory Laboratory (PVOL) [1]. This image repository is contributed by amateur astronomers worldwide and its images keep a record of atmospheric activity on Jupiter, Saturn and Uranus over the years. PVOL was created as an unfunded project that has been online since 2004. Its data content has been growing ever since then, now containing about 25,000 image files that cover the period 2000-2015. The main characteristic of PVOL, when compared with other amateur images repositories, is that it is built as a database with different searching tools. This characteristic has made PVOL an important research tool over the years for various scientific teams. Here we update the description of the data in PVOL and we discuss new development plans in the context of the Virtual European Solar and Planetary Access (VESPA) collaboration which will bring life to a Virtual Observatory for Planetary Sciences. The database is available in the following address:

  6. Atmospheric Escape by Magnetically Driven Wind from Gaseous Planets II --Effects of Magnetic Diffusion--

    CERN Document Server

    Tanaka, Yuki A; Inutsuka, Shu-ichiro

    2015-01-01

    We investigate roles of Alfvenic waves in the weakly-ionized atmosphere of hot Jupiters by carrying out non-ideal magnetohydrodynamic (MHD) simulations with Ohmic diffusion in one-dimensional magnetic flux tubes. Turbulence at the surface excites Alfven waves and they propagate upward to drive hot (~ 10^4 K) outflows. The magnetic diffusion plays an important role in the dissipation of the Alfvenic waves in the weakly ionized atmosphere of hot Jupiters. The mass-loss rate of the spontaneously driven planetary wind is considerably reduced, in comparison with that obtained from ideal MHD simulations because the Alfvenic waves are severely damped at low altitudes in the atmosphere, whereas the wave heating is still important in the heating of the upper atmosphere. Dependence on the surface temperature, planetary radius, and velocity dispersion at the surface is also investigated. We find an inversion phenomenon of the transmitted wave energy flux; the energy flux carried by Alfven waves in the upper atmosphere h...

  7. High-precision photometry by telescope defocussing - II. The transiting planetary system WASP-4

    DEFF Research Database (Denmark)

    Southworth, J.; Hinse, T. C.; Burgdorf, M. J.;

    2009-01-01

    We present and analyse light curves of four transits of the Southern hemisphere extrasolar planetary system WASP-4, obtained with a telescope defocused so the radius of each point spread function was 17 arcsec (44 pixels). This approach minimizes both random and systematic errors, allowing us...... to achieve scatters of between 0.60 and 0.88 mmag per observation over complete transit events. The light curves are augmented by published observations and analysed using the JKTEBOP code. The results of this process are combined with theoretical stellar model predictions to derive the physical properties...... of the WASP-4 system. We find that the mass and radius of the planet are Mb = 1.289+0.090-0.090+0.039-0.000MJup and Rb = 1.371+0.032-0.035+0.021-0.000RJup, respectively (statistical and systematic uncertainties). These quantities give a surface gravity and density of gb = 17.03+0.97-0.54ms-2 and ρb = 0...

  8. Central stars of planetary nebulae. II. New OB-type and emission-line stars

    Science.gov (United States)

    Weidmann, W. A.; Gamen, R.

    2011-07-01

    Context. There are more than 3000 confirmed and probably known Galactic planetary nebulae (PNe), but central star spectroscopic information is available for only 13% of them. Aims: We have undertaken a spectroscopic survey of the central stars in PNe to identify their spectral types. Methods: We performed spectroscopic observations at low resolution with the 2-m telescope at CASLEO, Argentina. Results: We present the spectra of 46 central stars of PNe, most of them are OB-type and emission-line stars. Based on data collected at the Complejo Astronómico El Leoncito (CASLEO), which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina y Universidades Nacionales de La Plata, Córdoba y San Juan, Argentina.The reduced spectra (FITS files) are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A172

  9. PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. II. H₂S AND SO₂ PHOTOCHEMISTRY IN ANOXIC ATMOSPHERES

    OpenAIRE

    Hu, Renyu; Seager, Sara; Bains, William

    2012-01-01

    Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H2S and SO2) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing...

  10. The potential impact of groove modes on Type II planetary migration

    CERN Document Server

    Meschiari, Stefano

    2008-01-01

    In this letter, we briefly describe the evolution of a variety of self-gravitating protoplanetary disk models that contain annular grooves (e.g. gaps) in their surface density. These grooves are inspired by the density gaps that are presumed to open in response to the formation of a giant planet. Our work provides an extension of the previously studied groove modes that are known in the context of stellar disks. The emergence of spiral gravitational instabilities (GI) is predicted via a generalized eigenvalue code that performs a linear analysis, and confirmed with hydrodynamical simulations. We find the presence of a groove drives a fast-growing two-armed mode in moderately massive disks, and extends the importance of self-gravitating instabilities down to lower disk masses than for which they would otherwise occur. We discuss the potential importance of this instability in the context of planet formation, e.g. the modification of the torques driving Type II migration.

  11. From Miras to planetary nebulae: Which path for stellar evolution?; Proceedings of the International Colloquium, Universite de Montpellier II, France, Sept. 4-7, 1989

    Science.gov (United States)

    Mennessier, M. O.; Omont, A.

    This book considers stellar evolution of Mira variables to planetary nebulae. Topics discussed include pulsation and shock waves; mass loss; circumstellar dust; maser emission and OH/IR stars; C stars; and post-AGB evolution to planetary nebulae, protoplanetary nebulae, and prewhite dwarfs and binaries. Papers are presented on pulsations of model Mira variables, the environment of Miras from interferometry, the physics of mass loss from AGB stars, the mixing length and the mass loss rate, dust formation and stellar wind, dust formation in circumstellar shells of Mira variables, the evolution of water masers on the AGB, and phase lags from OH/IR stars. Attention is also given to the variability of carbon stars, transfer reactions as neutron sources for the s-process, planetary nebulae as post-AGB objects, the kinematic structure of NGC 7139, the post-AGB evolution of low-mass stars, OH/IR stars as the progenitors of planetary nebulae, atmospheric parameters for pre-WD, and a new protoplanetary nebula.

  12. 'Photosystem II: the water splitting enzyme of photosynthesis and the origin of oxygen in our atmosphere'.

    Science.gov (United States)

    Barber, James

    2016-01-01

    About 3 billion years ago an enzyme emerged which would dramatically change the chemical composition of our planet and set in motion an unprecedented explosion in biological activity. This enzyme used solar energy to power the thermodynamically and chemically demanding reaction of water splitting. In so doing it provided biology with an unlimited supply of reducing equivalents needed to convert carbon dioxide into the organic molecules of life while at the same time produced oxygen to transform our planetary atmosphere from an anaerobic to an aerobic state. The enzyme which facilitates this reaction and therefore underpins virtually all life on our planet is known as Photosystem II (PSII). It is a pigment-binding, multisubunit protein complex embedded in the lipid environment of the thylakoid membranes of plants, algae and cyanobacteria. Today we have detailed understanding of the structure and functioning of this key and unique enzyme. The journey to this level of knowledge can be traced back to the discovery of oxygen itself in the 18th-century. Since then there has been a sequence of mile stone discoveries which makes a fascinating story, stretching over 200 years. But it is the last few years that have provided the level of detail necessary to reveal the chemistry of water oxidation and O-O bond formation. In particular, the crystal structure of the isolated PSII enzyme has been reported with ever increasing improvement in resolution. Thus the organisational and structural details of its many subunits and cofactors are now well understood. The water splitting site was revealed as a cluster of four Mn ions and a Ca ion surrounded by amino-acid side chains, of which seven provide direct ligands to the metals. The metal cluster is organised as a cubane structure composed of three Mn ions and a Ca2+ linked by oxo-bonds with the fourth Mn ion attached to the cubane. This structure has now been synthesised in a non-protein environment suggesting that it is a totally

  13. Developing Planetary Protection Technology: Microbial Diversity of the Mars Orbiter "Odyssey" and the Spacecraft Assembly and Encapsulation Facility II

    Science.gov (United States)

    La Duc, M. T.; Chen, F.; Baker, A.; Koukol, R. C.; Kern, R. G.; Venkateswaran, K. J.

    2001-12-01

    Sampling the surfaces of both spacecraft and their clean-room assembly facilities is crucial in monitoring the microbial burden associated with these pseudo-sterile, oligotrophic environments. Here, we present the results of a study in which several surface samples, retrieved from both the Mars Odyssey Spacecraft and the Kennedy Space Center (KSC) Spacecraft Assembly and Encapsulation Facility II (SAEF-II), were processed and evaluated by both molecular and traditional culture-based methods for microbial diversity. The findings of this study improve our current understanding of the microbial community structure, diversity, and dispersal in a spacecraft assembly facility, as well as physically associated with co-located spacecraft. Surfaces of 25 cm2 (spacecraft) or 0.4 m2 (SAEF-II) were swabbed or wiped, respectively, and were examined for total heterotrophic aerobes and spore-formers. Samples were further subjected to nucleic acid extraction, and 16S rDNA fragments were PCR amplified with eubacterial biased universal primers and cloned. Approximately 30 isolates grown by traditional culture-based techniques were included for 16S rDNA sequencing. For the most part, the population dynamics remained consistent when compared between the spacecraft and assembly facility libraries. Predominant microbes, as indicated by molecular methods, included members of the genera Variovorax and Aquaspirillum. Members of the Mesorhizobium, Bradyrhizobium, Enterococcus, Ralstonia, and Bacillus genera were also found to span the various libraries but in less abundance. Traditional culture-based techniques validated the presence of Bacillus and Ralstonia, while illuminating a larger diversity in revealing the presence of Staphylococcus, Comamonas, Microbacterium, and Actinomycetales. The bulk of these findings make sense, since species of Ralstonia, Rhizobium, Variovorax, and Bacillus are known to frequently inhabit rhizospheric environments, like that surrounding the KSC facility, and

  14. VizieR Online Data Catalog: Robo-AO Kepler planetary candidate survey. II. (Baranec+, 2016)

    Science.gov (United States)

    Baranec, C.; Ziegler, C.; Law, N. M.; Morton, T.; Riddle, R.; Atkinson, D.; Schonhut, J.; Crepp, J.

    2016-10-01

    We selected targets that we had not previously observed from the KOI Catalog based on the Q1-Q12 Kepler data (Rowe et al. 2015, Cat. J/ApJS/217/16). These targets were added to the Robo-AO intelligent observing queue and observed during the summer of 2013. We obtained high angular resolution images of 956 Kepler planet candidate host stars with the Robo-AO robotic laser AOs system over the course of 19 nights between 2013 July 21 and 2013 October 25, detailed in Table5. We also include 13 images from 2012 (2012 July 16-September 13) that required additional confirmation of the KOI position in the Robo-AO field of view. All the observations were performed in a queue-scheduled mode in combination with other science programs using the Robo-AO autonomous laser AO system mounted on the robotic 1.5m telescope at Palomar Observatory (exposure time: 90s; observation wavelengths: 600-950nm; FWHM resolution: 0.12''-0.15''; field of view: 44''*44''; pixel scale: 43.1mas/pix; detector format: 10242 pixels; targets observed/hour: 20). We obtained images of 50 KOIs with the NIRC2 instrument behind the Keck II AO system that were previously observed with Robo-AO and had evidence of a companion. Observations were conducted on 2013 June 25, 2013 August 24 and 25, 2014 August 17, and 2015 July 25 in the K, Ks, or Kp filters, and in the narrow mode of NIRC2 (9.952mas/pixel). (4 data files).

  15. Photochemistry in Terrestrial Exoplanet Atmospheres II: H2S and SO2 Photochemistry in Anoxic Atmospheres

    CERN Document Server

    Hu, Renyu; Bains, William

    2013-01-01

    Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H2S and SO2) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing. The most important finding is that both H2S and SO2 are chemically short-lived in virtually all types of atmospheres on terrestrial exoplanets, based on models of H2, N2, and CO2 atmospheres. This implies that direct detection of surface sulfur emission is unlikely, as their surface emission rates need to be extremely high (>1000 times Earth's volcanic sulfur emission) for these gases to build up to a detectable level. We also find that sulfur compounds emitted from the surface lead to photochemical formation of element...

  16. Hydrodynamics of Embedded Planets' First Atmospheres. II. A Rapid Recycling of Atmospheric Gas

    CERN Document Server

    Ormel, Chris W; Kuiper, Rolf

    2014-01-01

    Following Paper I we investigate the properties of atmospheres that form around small protoplanets embedded in a protoplanetary disc by conducting hydrodynamical simulations. These are now extended to three dimensions, employing a spherical grid centred on the planet. Compression of gas is shown to reduce rotational motions. Contrasting the 2D case, no clear boundary demarcates bound atmospheric gas from disc material; instead, we find an open system where gas enters the Bondi sphere at high latitudes and leaves through the midplane regions, or, vice versa, when the disc gas rotates sub-Keplerian. The simulations do not converge to a time-independent solution; instead, the atmosphere is characterized by a time-varying velocity field. Of particular interest is the timescale to replenish the atmosphere by nebular gas, $t_\\mathrm{replenish}$. It is shown that the replenishment rate, $M_\\mathrm{atm}/t_\\mathrm{replenish}$, can be understood in terms of a modified Bondi accretion rate, $\\sim$$R_\\mathrm{Bondi}^2\\rho...

  17. Measurements at the Planetary Emissivity Laboratory in Support of MARA and the TIR Imager on the JAXA Hayabusa II Mission

    Science.gov (United States)

    Helbert, J.; Maturilli, A.; Grott, M.; Knollenberg, J.; Okada, T.; Kührt, E.

    2012-03-01

    At the Planetary Emissivity Laboratory (PEL) at DLR we perform measurements on analog materials to explore the possibility of mineralogical studies with the thermal infrared imager and the radiometer MARA (MAscot RAdiometer) on MASCOT.

  18. Five-day planetary waves in the middle atmosphere from Odin satellite data and ground-based instruments in Northern Hemisphere summer 2003, 2004, 2005 and 2007

    Directory of Open Access Journals (Sweden)

    A. Belova

    2008-11-01

    Full Text Available A number of studies have shown that 5-day planetary waves modulate noctilucent clouds and the closely related Polar Mesosphere Summer Echoes (PMSE at the summer mesopause. Summer stratospheric winds should inhibit wave propagation through the stratosphere and, although some numerical models (Geisler and Dickinson, 1976 do show a possibility for upward wave propagation, it has also been suggested that the upward propagation may in practice be confined to the winter hemisphere with horizontal propagation of the wave from the winter to the summer hemisphere at mesosphere heights causing the effects observed at the summer mesopause. It has further been proposed (Garcia et al., 2005 that 5-day planetary waves observed in the summer mesosphere could be excited in-situ by baroclinic instability in the upper mesosphere. In this study, we first extract and analyze 5-day planetary wave characteristics on a global scale in the middle atmosphere (up to 54 km in temperature, and up to 68 km in ozone concentration using measurements by the Odin satellite for selected days during northern hemisphere summer from 2003, 2004, 2005 and 2007. Second, we show that 5-day temperature fluctuations consistent with westward-traveling 5-day waves are present at the summer mesopause, using local ground-based meteor-radar observations. Finally we examine whether any of three possible sources of the detected temperature fluctuations at the summer mesopause can be excluded: upward propagation from the stratosphere in the summer-hemisphere, horizontal propagation from the winter-hemisphere or in-situ excitation as a result of the baroclinic instability. We find that in one case, far from solstice, the baroclinic instability is unlikely to be involved. In one further case, close to solstice, upward propagation in the same hemisphere seems to be ruled out. In all other cases, all or any of the three proposed mechanisms are consistent with the observations.

  19. The optical reflector system for the CANGAROO-II imaging atmospheric Cherenkov telescope

    CERN Document Server

    Kawachi, A; Jimbo, J; Kamei, S; Kifune, T; Kubo, H; Kushida, J; Le Bohec, S; Miyawaki, K; Mori, M; Nishijima, K; Patterson, J R; Suzuki, R; Tanimori, T; Yanagita, S; Yoshikoshi, T; Yuki, A

    2001-01-01

    A new imaging atmospheric Cherenkov telescope (CANGAROO-II) with a light-weight reflector has been constructed. Light, robust, and durable mirror facets of containing CFRP (Carbon Fiber Reinforced Plastic) laminates were developed for the telescope. The attitude of each facet can be adjusted by stepping motors. In this paper, we describe the design, manufacturing, alignment procedure, and the performance of the CANGAROO-II optical reflector system.

  20. Empirical calibration of the near-IR Ca II triplet - II. The stellar atmospheric parameters

    CERN Document Server

    Cenarro, A J; Cardiel, N; Pedraz, S; Peletier, R F; Vazdekis, A

    2001-01-01

    We present an homogeneous set of stellar atmospheric parameters (Teff, log g, [Fe/H]) for a sample of about 700 field and cluster stars which constitute a new stellar library in the near-infrared developed for stellar population synthesis in this spectral region (8350-9020 Angstrom). Having compiled the available atmospheric data in the literature for field stars, we have found systematic deviations between the atmospheric parameters from different bibliographic references. The Soubiran, Katz & Cayrel (1998) sample of stars with very well determined fundamental parameters has been taken as our standard reference system, and other papers have been calibrated and bootstrapped against it. The obtained transformations are provided in this paper. Once most of the datasets were on the same system, final parameters were derived by performing error weighted means. Atmospheric parameters for cluster stars have also been revised and updated according to recent metallicity scales and colour-temperature relations.

  1. The formation of IRIS diagnostics II. The formation of the Mg II h&k lines in the solar atmosphere

    CERN Document Server

    Leenaarts, J; Carlsson, M; Uitenbroek, H; de Pontieu, B

    2013-01-01

    NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations requires forward modeling of Mg II h&k line formation from 3D radiation-MHD models. We compute the vertically emergent h&k intensity from a snapshot of a dynamic 3D radiation-MHD model of the solar atmosphere, and investigate which diagnostic information about the atmosphere is contained in the synthetic line profiles. We find that the Doppler shift of the central line depression correlates strongly with the vertical velocity at optical depth unity, which is typically located less than 200 km below the transition region (TR). By combining the Doppler shifts of the h and the k line we can retrieve the sign of the velocity gradient just below the TR. The intensity in the central line depression is anticorrelated with the formati...

  2. Wave activity (planetary, tidal throughout the middle atmosphere (20-100km over the CUJO network: Satellite (TOMS and Medium Frequency (MF radar observations

    Directory of Open Access Journals (Sweden)

    A. H. Manson

    2005-02-01

    Full Text Available Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT is studied using combinations of ground-based (GB and satellite instruments (2000-2002. The relatively new MFR (medium frequency radar at Platteville (40° N, 105° W has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opportunity comprises systems at London (43° N, 81° W, Platteville (40° N, 105° W, Saskatoon (52° N, 107° W, Wakkanai (45° N, 142° E and Yamagawa (31° N, 131° E. It offers a significant 7000-km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14° at two longitudes. Satellite data mainly involve the daily values of the total ozone column measured by the Earth Probe (EP TOMS (Total Ozone Mapping Spectrometer and provide a measure of tropopause-lower stratospheric planetary wave activity, as well as ozone variability.

    Climatologies of ozone and winds/tides involving frequency versus time (wavelet contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40° N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km heights. Both direct planetary wave (PW propagation into the MLT, nonlinear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS satellite data to demonstrate the differences between lower atmospheric

  3. Wave activity (planetary, tidal) throughout the middle atmosphere (20-100km) over the CUJO network: Satellite (TOMS) and Medium Frequency (MF) radar observations

    Science.gov (United States)

    Manson, A. H.; Meek, C. E.; Chshyolkova, T.; Avery, S. K.; Thorsen, D.; MacDougall, J. W.; Hocking, W.; Murayama, Y.; Igarashi, K.

    2005-02-01

    Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT) is studied using combinations of ground-based (GB) and satellite instruments (2000-2002). The relatively new MFR (medium frequency radar) at Platteville (40° N, 105° W) has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opportunity) comprises systems at London (43° N, 81° W), Platteville (40° N, 105° W), Saskatoon (52° N, 107° W), Wakkanai (45° N, 142° E) and Yamagawa (31° N, 131° E). It offers a significant 7000-km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14°) at two longitudes. Satellite data mainly involve the daily values of the total ozone column measured by the Earth Probe (EP) TOMS (Total Ozone Mapping Spectrometer) and provide a measure of tropopause-lower stratospheric planetary wave activity, as well as ozone variability. Climatologies of ozone and winds/tides involving frequency versus time (wavelet) contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40° N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km) heights. Both direct planetary wave (PW) propagation into the MLT, nonlinear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS satellite data to demonstrate the differences between lower atmospheric and MLT wave motions and their

  4. Spectral Signatures of Photosynthesis. II. Coevolution with Other Stars And The Atmosphere on Extrasolar Worlds

    Science.gov (United States)

    Kiang, Nancy Y.; Segura, Antígona; Tinetti, Giovanna; Govindjee; Blankenship, Robert E.; Cohen, Martin; Siefert, Janet; Crisp, David; Meadows, Victoria S.

    2007-02-01

    As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take previously simulated planetary atmospheric compositions for Earth-like planets around observed F2V and K2V, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O2 content in case anoxygenic photosynthesis dominates. With a line-by-line radiative transfer model, we calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the near-infrared, in bands at 0.93-1.1 μm, 1.1-1.4 μm, 1.5-1.8 μ m, and 1.8-2.5 μm. However, underwater organisms will be restricted to wavelengths shorter than 1.4 μm and more likely below 1.1 μm. M star planets without oxygenic photosynthesis will have photon fluxes above 1.6 μm curtailed by methane. Longer-wavelength, multi-photo-system series would reduce the quantum yield but could allow for oxygenic photosystems at longer wavelengths. A wavelength of 1.1 μm is a possible upper cutoff for electronic transiprotions versus only vibrational energy; however, this cutoff is not strict, since such energetics depend on molecular configuration. M star planets could be a half to a tenth as productive as Earth in the visible, but exceed Earth if useful photons extend to 1.1 μm for anoxygenic photosynthesis. Under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth. Key Words: Photosynthesis-Astrobiology - Photosynthetic pigments - Oxygenic photosynthesis - Anoxygenic

  5. Airships for Planetary Exploration

    Science.gov (United States)

    Colozza, Anthony

    2004-01-01

    The feasibility of utilizing an airship for planetary atmospheric exploration was assessed. The environmental conditions of the planets and moons within our solar system were evaluated to determine their applicability for airship flight. A station-keeping mission of 50 days in length was used as the baseline mission. Airship sizing was performed utilizing both solar power and isotope power to meet the baseline mission goal at the selected planetary location. The results show that an isotope-powered airship is feasible within the lower atmosphere of Venus and Saturn s moon Titan.

  6. On the polarization angle of skylight reflected by natural surfaces: Properties and application for remote sensing of planetary atmospheres

    Directory of Open Access Journals (Sweden)

    J. Chowdhary

    2011-09-01

    Full Text Available In this study, we focus on the polarization angle of light scattered by terrestrial atmosphere-surface systems. The polarization angle describes the orientation of the plane in which the linearly polarized portion of light propagates. We show for skylight how this angle varies with the solar zenith angle and that, for skylight reflected by natural surfaces, these variations remain the same for wide ranges of atmospheric conditions and surface properties. This provides a tool for extracting scattering properties of the atmosphere from remote sensing observations of the Earth without any knowledge of the underlying surface. We demonstrate this principle for simulated data, and apply it to observations obtained by an airborne polarimeter over open oceans.

  7. Development of an Electrostatic Precipitator to Remove Martian Atmospheric Dust from ISRU Gas Intakes During Planetary Exploration Missions

    Science.gov (United States)

    Clements, J. Sidney; Thompson, Samuel M.; Cox, Nathan D.; Johansen, Michael R.; Williams, Blakeley S.; Hogue, Michael D.; Lowder, M. Loraine; Calle, Carlos I.

    2011-01-01

    Manned exploration missions to Mars will need dependable in situ resource utilization (ISRU) for the production of oxygen and other commodities. One of these resources is the Martian atmosphere itself, which is composed of carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), oxygen (0.13%), carbon monoxide (0.07%), and water vapor (0.03%), as well as other trace gases. However, the Martian atmosphere also contains relatively large amounts of dust, uploaded by frequent dust devils and high Winds. To make this gas usable for oxygen extraction in specialized chambers requires the removal of most of the dust. An electrostatic precipitator (ESP) system is an obvious choice. But with an atmospheric pressure just one-hundredth of Earth's, electrical breakdown at low voltages makes the implementation of the electrostatic precipitator technology very challenging. Ion mobility, drag forces, dust particle charging, and migration velocity are also affected because the low gas pressure results in molecular mean free paths that are approximately one hundred times longer than those at Earth .atmospheric pressure. We report here on our efforts to develop this technology at the Kennedy Space Center, using gases with approximately the same composition as the Martian atmosphere in a vacuum chamber at 9 mbars, the atmospheric pressure on Mars. We also present I-V curves and large particle charging data for various versions of wire-cylinder and rod-cylinder geometry ESPs. Preliminary results suggest that use of an ESP for dust collection on Mars may be feasible, but further testing with Martian dust simulant is required.

  8. Incorporating Planetary-Scale Waves Into the VTGCM: Understanding the Waves Impact on the Upper Atmosphere of Venus.

    Science.gov (United States)

    Brecht, A. S.; Bougher, S. W.; Shields, D.; Liu, H.

    2017-01-01

    Venus has proven to have a very dynamic upper atmosphere. The upper atmosphere of Venus has been observed for many decades by multiple means of observation (e.g. ground-based, orbiters, probes, fly-by missions going to other planets). As of late, the European Space Agency Venus Express (VEX) orbiter has been a main observer of the Venusian atmosphere. Specifically, observations of Venus' O2 IR nightglow emission have been presented to show its variability. Nightglow emission is directly connected to Venus' circulation and is utilized as a tracer for the atmospheric global wind system. More recent observations are adding and augmenting temperature and density (e.g. CO, CO2, SO2) datasets. These additional datasets provide a means to begin analyzing the variability and study the potential drivers of the variability. A commonly discussed driver of variability is wave deposition. Evidence of waves has been observed, but these waves have not been completely analyzed to understand how and where they are important. A way to interpret the observations and test potential drivers is by utilizing numerical models.

  9. Semi-classical H2-broadening coefficients of 12CH3D rovibrational lines and their temperature dependence for planetary atmosphere modeling

    Science.gov (United States)

    Sinyakova, T.; Buldyreva, J.

    2017-01-01

    Theoretical hydrogen-broadening coefficients and associated temperature exponents for 12CH3D (J, K) lines in parallel (ΔK = 0) bands are calculated by a semi-classical approach based on a rigorous consideration of the active molecule as a symmetric top, a model intermolecular potential comprising both short- and long-range interactions, and exact classical trajectories. The leading potential terms are shown to provide a realistic description of line broadening in comparison with scarce measurements available in the literature. The calculations performed for 296, 240 and 190 K are used to extract the line-width temperature-dependence exponents for the typical temperature range of atmospheric interest ∼200-300 K. Detailed P-Q-R-line lists are provided for large intervals of quantum numbers (0 ≤ J ≤ 20, 0 ≤ K ≤ J) requested for remote sensing of planetary atmospheres, in particular those of outer planets and their moons. With negligible vibrational dependence of CH3D line-widths and estimated as negligible their sub-branch dependence, these data can be also employed for perpendicular bands.

  10. Anisotropic macroturbulence and diffusion associated with a westward zonal jet: From laboratory to planetary atmospheres and oceans

    Science.gov (United States)

    Galperin, Boris; Hoemann, Jesse; Espa, Stefania; Di Nitto, Gabriella; Lacorata, Guglielmo

    2016-12-01

    Turbulence with inverse energy cascade and its transport properties are investigated experimentally in a flow associated with a westward propagating jet. Turbulence and the jet were produced by an electromagnetic force in a rotating tank filled with an electrolytic saline solution. The parabolic free surface emulated the topographic β effect which evoked the zonation. The spectral and transport flow characteristics were highly anisotropic. Turbulence is diagnosed by exploring the analogy between vertical and horizontal turbulent overturns in, respectively, stably stratified and quasigeostrophic flows which gives rise to a method of potential vorticity (PV) monotonizing. The anisotropization of transport properties of the flow is investigated using the finite scale Lyapunov exponent technique. After initial exponential particle separation, radial (meridional in geophysical and planetary applications) diffusion attains a short-ranged Richardson regime which transitions to the Taylor (scale-independent diffusivity) one. The azimuthal (zonal) diffusion exhibits a double-plateau structure which attains a superdiffusive regime on large scales. The transition to the Taylor regime for the radial diffusion takes place at a scale of turbulence anisotropization. The radial eddy diffusivity in both regimes as well as the transition scale are all determined by the rate of the inverse energy cascade, ɛ , that can be diagnosed by the PV monotonizing. Conversely, ɛ can be deduced from the scale of the Richardson-Taylor regime transition in the radial eddy diffusivity which, thus, provides an additional tool of diagnosing anisotropic macroturbulence with inverse energy cascade.

  11. Anisotropic macroturbulence and diffusion associated with a westward zonal jet: From laboratory to planetary atmospheres and oceans.

    Science.gov (United States)

    Galperin, Boris; Hoemann, Jesse; Espa, Stefania; Di Nitto, Gabriella; Lacorata, Guglielmo

    2016-12-01

    Turbulence with inverse energy cascade and its transport properties are investigated experimentally in a flow associated with a westward propagating jet. Turbulence and the jet were produced by an electromagnetic force in a rotating tank filled with an electrolytic saline solution. The parabolic free surface emulated the topographic β effect which evoked the zonation. The spectral and transport flow characteristics were highly anisotropic. Turbulence is diagnosed by exploring the analogy between vertical and horizontal turbulent overturns in, respectively, stably stratified and quasigeostrophic flows which gives rise to a method of potential vorticity (PV) monotonizing. The anisotropization of transport properties of the flow is investigated using the finite scale Lyapunov exponent technique. After initial exponential particle separation, radial (meridional in geophysical and planetary applications) diffusion attains a short-ranged Richardson regime which transitions to the Taylor (scale-independent diffusivity) one. The azimuthal (zonal) diffusion exhibits a double-plateau structure which attains a superdiffusive regime on large scales. The transition to the Taylor regime for the radial diffusion takes place at a scale of turbulence anisotropization. The radial eddy diffusivity in both regimes as well as the transition scale are all determined by the rate of the inverse energy cascade, ε, that can be diagnosed by the PV monotonizing. Conversely, ε can be deduced from the scale of the Richardson-Taylor regime transition in the radial eddy diffusivity which, thus, provides an additional tool of diagnosing anisotropic macroturbulence with inverse energy cascade.

  12. Planetary science: Eris under scrutiny

    Science.gov (United States)

    Gulbis, Amanda

    2011-10-01

    A stellar occultation by the dwarf planet Eris provides a new estimate of its size. It also reveals a surprisingly bright planetary surface, which could indicate the relatively recent condensation of a putative atmosphere. See Letter p.493

  13. Planetary polarization nephelometer

    NARCIS (Netherlands)

    Banfield, D.; Dissly, R.; Mishchenko, M.; Muñoz, O.; Roos-Serote, M.; Stam, D.M.; Volten, H.; Wilson, A.

    2004-01-01

    We have proposed to develop a polarization nephelometer for use on future planetary descent probes. It will measure both the scattered intensity and polarization phase functions of the aerosols it encounters descending through an atmosphere. These measurements will be taken at two wavelengths

  14. Planetary polarization nephelometer

    NARCIS (Netherlands)

    Banfield, D.; Dissly, R.; Mishchenko, M.; Muñoz, O.; Roos-Serote, M.; Stam, D.M.; Volten, H.; Wilson, A.

    2004-01-01

    We have proposed to develop a polarization nephelometer for use on future planetary descent probes. It will measure both the scattered intensity and polarization phase functions of the aerosols it encounters descending through an atmosphere. These measurements will be taken at two wavelengths separa

  15. Spectral signatures of photosynthesis II: coevolution with other stars and the atmosphere on extrasolar worlds

    CERN Document Server

    Kiang, N Y; Tinetti, G; Blankenship, R E; Cohen, M; Siefert, J; Crisp, D; Meadows, V S; Kiang, Nancy Y.; Segura, Antigona; Tinetti, Giovanna; Blankenship, Robert E.; Cohen, Martin; Siefert, Janet; Crisp, David; Meadows, Victoria S.

    2007-01-01

    As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take planetary atmospheric compositions simulated by Segura, et al. (2003, 2005) for Earth-like planets around observed F2V and K2V stars, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O2 content in case anoxygenic photosynthesis dominates. We calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the NIR, in bands at 0.93-1.1 microns, 1.1-1.4 microns, 1.5-1.8 microns, and 1.8-2.5 microns. In additio...

  16. THE FOREST-ATMOSPHERIC CARBON TRANSFER AND STORAGE-II (FACTS-II): ASPEN FACE PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    KARNOSKY,D.F.; HENDREY,G.; PREGITZER,K.; ISEBRANDS,J.G.

    1998-02-01

    The FACTS II (ASPEN FACE) infrastructure including 12 FACE [Free-Air Carbon dioxide Enrichment] rings, a central control facility, a central CO{sub 2} and O{sub 2} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  17. The Forest-Atmospheric Carbon Transfer and Storage-II (FACTS-II): Aspen FACE project

    Energy Technology Data Exchange (ETDEWEB)

    Karnosky, D.F.; Pregitzer, K. [Michigan Technological Univ., Houghton, MI (United States). School of Forestry and Wood Products; Hendrey, G. [Brookhaven National Lab., Upton, NY (United States); Isebrands, J.G. [Forest Service, Rhinelander, WI (United States)

    1998-02-01

    The FACTS II (Aspen FACE) infrastructure including 12 FACE rings, a central control facility, a central CO{sub 2} and O{sub 3} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  18. Planetary Radar

    Science.gov (United States)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

    This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

  19. Discovery of Rotational Modulations in the Planetary-Mass Companion 2M1207b: Intermediate Rotation Period and Heterogeneous Clouds in a Low Gravity Atmosphere

    CERN Document Server

    Zhou, Yifan; Schneider, Glenn; Marley, Mark S; Showman, Adam P

    2015-01-01

    Rotational modulations of brown dwarfs have recently provided powerful constraints on the properties of ultra-cool atmospheres, including longitudinal and vertical cloud structures and cloud evolution. Furthermore, periodic light curves directly probe the rotational periods of ultra-cool objects. We present here, for the first time, time-resolved high-precision photometric measurements of a planetary-mass companion, 2M1207b. We observed the binary system with HST/WFC3 in two bands and with two spacecraft roll angles. Using point spread function-based photometry, we reach a nearly photon-noise limited accuracy for both the primary and the secondary. While the primary is consistent with a flat light curve, the secondary shows modulations that are clearly detected in the combined light curve as well as in different subsets of the data. The amplitudes are 1.36% in the F125W and 0.78% in the F160W filters, respectively. By fitting sine waves to the light curves, we find a consistent period of $10.7^{+1.2}_{-0.6}$ ...

  20. Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)

    CERN Document Server

    Ribas, I; Güdel, M; Audard, M

    2004-01-01

    We report on the results of the Sun in Time multi-wavelength program (X-rays to the UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and magnetic properties of the Sun during its evolution across the main sequence. The present paper focuses on the latter goal, which has the ultimate purpose of providing the spectral irradiance evolution of solar-type stars to be used in the study and modeling of planetary atmospheres. The results from the Sun in Time program suggest that the coronal X-ray-EUV emissions of the young main-sequence Sun were ~100-1000 times stronger than those of the present Sun. Similarly, the transition region and chromospheric FUV-UV emissions of the young Sun are expected to be 20-60 and 10-20 times stronger, respectively, than at present. When considering the integrated high-energy emission from 1 to 1200 A, the resulting relationship indicates that the solar high-energy flux was about 2.5 times ...

  1. Spacecraft and Stellar Occultations by Turbulent Planetary Atmospheres. A Theoretical Investigation of Various Wave Propagation Effects and Their Impact on Derived Profiles of Refractivity, Temperature and Pressure,

    Science.gov (United States)

    1981-05-08

    fluctuations are a small fraction only of the ambient refractivity. The intensity fluctuations also depend on the radiation wavelength X, whereas the...atmospheric 48 Fresnel zone. We also find that for Kolmogorov turbulence the bias in phase path scales with radiation wavelength as X" , implying that an...iII nije Li 2r,,,, a, aIs the( impact parametehr) b\\ thu( solair dix iiti tld !wld. \\wi\\ )Y’l l~iiss Is tw to1mill to) sign ificatitl\\ degrade the mia

  2. The resonant structure of Jupiter's Trojan asteroids - II. What happens for different configurations of the planetary system

    Science.gov (United States)

    Robutel, P.; Bodossian, J.

    2009-10-01

    In a previous paper, we have found that the resonance structure of the present Jupiter Trojan swarms could be split up into four different families of resonances. Here, in a first step, we generalize these families in order to describe the resonances occurring in Trojan swarms embedded in a generic planetary system. The location of these families changes under a modification of the fundamental frequencies of the planets and we show how the resonant structure would evolve during a planetary migration. We present a general method, based on the knowledge of the fundamental frequencies of the planets and on those that can be reached by the Trojans, which makes it possible to predict and localize the main events arising in the swarms during migration. In particular, we show how the size and stability of the Trojan swarms are affected by the modification of the frequencies of the planets. Finally, we use this method to study the global dynamics of the Jovian Trojan swarms when Saturn migrates outwards. Besides the two resonances found by Morbidelli et al. which could have led to the capture of the current population just after the crossing of the 2:1 orbital resonance, we also point out several sequences of chaotic events that can influence the Trojan population.

  3. The resonant structure of Jupiter's Trojans asteroids-II. What happens for different configurations of the planetary system

    CERN Document Server

    Robutel, Philippe

    2008-01-01

    In a previous paper, we have found that the resonance structure of the present Jupiter Trojans swarms could be split up into four different families of resonances. Here, in a first step, we generalize these families in order to describe the resonances occurring in Trojans swarms embedded in a generic planetary system. The location of these families changing under a modification of the fundamental frequencies of the planets, we show how the resonant structure would evolve during a planetary migration. We present a general method, based on the knowledge of the fundamental frequencies of the planets and on those that can be reached by the Trojans, which makes possible the prediction and the localization of the main events arising in the swarms during migration. In particular, we show how the size and stability of the Trojans swarms are affected by the modification of the frequencies of the planets. Finally, we use this method to study the global dynamics of the Jovian Trojans swarms when Saturn migrates outward....

  4. The Importance and Current Limitations of Planetary Boundary Layer (PBL) Retrieval from Space for Land-Atmosphere Coupling Studies

    Science.gov (United States)

    Santanello, J. A., Jr.; Schaefer, A.

    2016-12-01

    There is an established need for improved PBL remote sounding over land for hydrology, land-atmosphere (L-A), PBL, cloud/convection, pollution/chemistry studies and associated model evaluation and development. Most notably, the connection of surface hydrology (through soil moisture) to clouds and precipitation relies on proper quantification of water's transport through the coupled system, which is modulated strongly by PBL structure, growth, and feedback processes such as entrainment. In-situ (ground-based or radiosonde) measurements will be spatially limited to small field campaigns for the foreseeable future, so satellite data is a must in order to understand these processes globally. The scales of these applications require diurnal resolution (e.g. 3-hourly or finer) at PBL coupling and water and energy cycles at their native scales. Today's satellite sensors (e.g. advanced IR, GEO, lidar, GPS-RO) do not reach close to these targets in terms of accuracy or resolution, and each of these sensors has some advantages but even more limitations that make them impractical for PBL and L-A studies. Unfortunately, there is very little attention or planning (short or long-term) in place for improving lower tropospheric sounding over land, and as a result PBL and L-A interactions have been identified as `gaps' in current programmatic focal areas. It is therefore timely to assess how these technologies can be leveraged, combined, or evolved in order to form a dedicated mission or sub-mission to routinely monitor the PBL on diurnal timescales. In addition, improved PBL monitoring from space needs to be addressed in the next Decadal Survey. In this talk, the importance of PBL information (structure, evolution) for L-A coupling diagnostics and model development will be summarized. The current array of PBL retrieval methods and products from space will then be assessed in terms of meeting the needs of these models, diagnostics, and scales, with a look forward as to how this can

  5. Determination of the Atmospheric Neutrino Flux and Searches for New Physics with AMANDA-II

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Klein, Spencer; Collaboration, IceCube

    2009-06-02

    The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance (VLI) or quantum decoherence (QD). Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on VLI and QD parameters using a maximum likelihood method. Given the absence of evidence for new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.

  6. Ellerman Bombs, Type II White-light Flares and Magnetic Reconnection in the Solar Lower Atmosphere

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ellerman bombs and Type II white-light flares share many common features despite the large energy gap between them. Both are considered to result from local heating in the solar lower atmosphere. This paper presents numerical simulations of magnetic reconnection occurring in such a deep atmosphere, with the aim to account for the common features of the two phenomena. Our numerical results manifest the following two typical characteristics of the assumed reconnection process: (1) magnetic reconnection saturates in ~600-900 s, which is just the lifetime of the two phenomena; (2) ionization in the upper chromosphere consumes quite a large part of the energy released through reconnection, making the heating effect most significant in the lower chromosphere. The application of the reconnection model to the two phenomena is discussed in detail.

  7. Determination of the atmospheric neutrino flux and searches for new physics with AMANDA-II

    Science.gov (United States)

    Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Breder, D.; Burgess, T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Day, C. T.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; De Young, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Heise, J.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Klepser, S.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Lauer, R.; Leich, H.; Lennarz, D.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Merck, M.; Mészáros, P.; Middell, E.; Milke, N.; Miyamoto, H.; Mohr, A.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Satalecka, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; Voigt, B.; Walck, C.; Waldenmaier, T.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebusch, C. H.; Wiedemann, A.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.

    2009-05-01

    The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance or quantum decoherence. Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on violation of Lorentz invariance and quantum decoherence parameters using a maximum likelihood method. Given the absence of evidence for new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.

  8. Transit Timing Variation of Near-Resonance Planetary Pairs. II. Confirmation of 30 planets in 15 Multiple Planet Systems

    CERN Document Server

    Xie, Ji-Wei

    2013-01-01

    Following on from Paper I in our series (Xie 2012), we report the confirmation by Transit Timing Variations (TTVs) of a further 30 planets in 15 multiple planet systems, using the publicly available Kepler light curves (Q0-Q16). All of these fifteen pairs are near first-order Mean Motion Resonances (MMR), showing sinusoidal TTVs consistent with theoretically predicted periods, which demonstrate they are orbiting and interacting in the same systems. Although individual masses cannot be accurately extracted based only on TTVs (because of the well known degeneracy between mass and eccentricity), the measured TTV phases and amplitudes can still place relatively tight constraints on their mass ratios and upper limits on their masses, which confirm their planetary nature. Some of these systems (KOI-274, KOI-285, KOI-370 and KOI-2672) are relatively bright and thus suitable for further follow-up observations.

  9. Binary planetary nebulae nuclei towards the Galactic bulge. II. A penchant for bipolarity and low-ionisation structures

    CERN Document Server

    Miszalski, B; Parker, Q A; Moffat, A F J

    2009-01-01

    Considerable effort has been applied towards understanding the precise shaping mechanisms responsible for the diverse range of morphologies exhibited by planetary nebulae (PNe). A binary companion is increasingly gaining support as a dominant shaping mechanism, however morphological studies of the few PNe that we know for certain were shaped by binary evolution are scarce or biased. Newly discovered binary central stars (CSPN) from the OGLE-III photometric variability survey have significantly increased the sample of post common-envelope (CE) nebulae available for morphological analysis. We present Gemini South narrow-band images for most of the new sample to complement existing data in a qualitative morphological study of 30 post-CE nebulae. Nearly 30% of nebulae have canonical bipolar morphologies, however this rises to 60% once inclination effects are incorporated with the aid of geometric models. This is the strongest observational evidence yet linking CE evolution to bipolar morphologies. A higher than a...

  10. Radial metallicity gradients in spiral galaxies from H II regions and planetary nebulae: probing galactic chemical evolution

    Science.gov (United States)

    Stanghellini, Letizia

    2015-08-01

    Radial metallicity gradients, typically observed in spiral galaxies, are excellent constraints for chemical evolution models. The contemporary studies of the two stellar populations, whose progenitors have formed at different times, yield to the chemical and time constraining of the models. In this context, planetary nebula and HII region analysis proved to be ideal two-epochs test populations. We present an assortment of galaxies whose oxygen abundances have been determined both with weak- and strong-line methods, and whose radial metallicity gradients and their evolution in time have disclosed very interesting correlations with the galaxy characteristics. New results from our Gemini/GMOS observations, and a review of the best literature data, set the stage for a better understanding of spiral galaxy evolution.

  11. Meteorological and Back Trajectory Modeling for the Rocky Mountain Atmospheric Nitrogen and Sulfur Study II

    Directory of Open Access Journals (Sweden)

    Kristi A. Gebhart

    2014-01-01

    Full Text Available The Rocky Mountain Atmospheric Nitrogen and Sulfur (RoMANS II study with field operations during November 2008 through November 2009 was designed to evaluate the composition and sources of reactive nitrogen in Rocky Mountain National Park, Colorado, USA. As part of RoMANS II, a mesoscale meteorological model was utilized to provide input for back trajectory and chemical transport models. Evaluation of the model's ability to capture important transport patterns in this region of complex terrain is discussed. Previous source-receptor studies of nitrogen in this region are also reviewed. Finally, results of several back trajectory analyses for RoMANS II are presented. The trajectory mass balance (TrMB model, a receptor-based linear regression technique, was used to estimate mean source attributions of airborne ammonia concentrations during RoMANS II. Though ammonia concentrations are usually higher when there is transport from the east, the TrMB model estimates that, on average, areas to the west contribute a larger mean fraction of the ammonia. Possible reasons for this are discussed and include the greater frequency of westerly versus easterly winds, the possibility that ammonia is transported long distances as ammonium nitrate, and the difficulty of correctly modeling the transport winds in this area.

  12. Planetary Magnetism

    Science.gov (United States)

    Connerney, J. E. P.

    2007-01-01

    The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

  13. Planetary-scale hydraulic jumps and transonic jet-streaks in the MACDA reanalysis of the Martian atmosphere: a comparison with Earth's lower mesosphere

    Science.gov (United States)

    Dowling, Timothy E.; Bradley, Mary Elizabeth; Lewis, Stephen R.; Read, Peter L.

    2016-10-01

    We have analyzed the Mars MACDA V1.0 global reanalysis on potential-temperature surfaces, θ, over the range θ = 400 to 900 K (~30 to ~60 km). The strongest seasonal wind, the northern-winter polar jet, exhibits two intriguing features: i) transonic jet streaks and ii) the juxtaposition of regions of shooting and tranquil flow, in the sense of Froude-number hydraulics, which suggests a planetary-scale hydraulic jump. Mesoscale bores have been studied on Mars, but to our knowledge the above two features have not been reported elsewhere. To characterize the basic state, we examine scatter plots of Ertel potential vorticity, Q, versus Bernoulli streamfunction, B, and fit the linear model Q/Q0 = 1 - μ0 (B-B0). In autumn, winter and spring, the nondimensionalized correlation parameter, μ'0 = (NH)2 μ0, in mid-latitudes is positive and nearly constant in time. Its value is close to unity at the bottom of the study region and gradually decreases with increasing θ (increasing altitude). In northern summer it swings negative. These attributes match Earth's lower mesosphere (θ = 2000 to 3000 K; ~48 to ~62 km). In southern summer, Ls ~ 270○, a hypsometric flaring of the θ layers, which is not seen in northern summer, is associated with the previously reported reduction of Q to approximately zero across the entire southern hemisphere and northern tropics. Between each winter polar jet and pole, especially in the north, there is a large spread of Q over a small domain of B, which is unlike Earth and may be related to the aforementioned hydraulic jump. We are currently examining 3D Lagrangian fluid trajectories to better characterize the rotating hydraulics of the system as a function of season.

  14. The Abundances of Light Neutron-Capture Elements in Planetary Nebulae II. s-process Enrichments and Interpretation

    CERN Document Server

    Sterling, N C

    2007-01-01

    We present the results of a large-scale survey of neutron(n)-capture elements in Galactic planetary nebulae (PNe), undertaken to study enrichments from s-process nucleosynthesis in their progenitor stars. From new K band observations of over 100 PNe supplemented by data from the literature, we have detected the emission lines [Kr III] 2.199 and/or [Se IV] 2.287 $\\mu$m in 81 of 120 objects. We determine Se and Kr elemental abundances, employing ionization correction formulae derived in the first paper of this series. We find a significant range in Se and Kr abundances, from near solar (no enrichment) to enhanced by >1.0 dex relative to solar, which we interpret as self-enrichment due to in situ s-process nucleosynthesis. Kr tends to be more strongly enriched than Se; in 18 objects exhibiting both Se and Kr emission, we find that [Kr/Se] = 0.5$\\pm$0.2. Our survey has increased the number of PNe with n-capture element abundance determinations by a factor of ten, enabling us for the first time to search for corre...

  15. Warm Ice Giant GJ 3470b. II Revised Planetary and Stellar Parameters from Optical to Near-infrared Transit Photometry

    CERN Document Server

    Biddle, Lauren I; Crossfield, Ian J M; Fulton, Benjamin J; Ciceri, Simona; Eastman, Jason; Barman, Travis; Mann, Andrew W; Henry, Gregory W; Howard, Andrew W; Williamson, Michael H; Sinukoff, Evan; Dragomir, Diana; Vican, Laura; Mancini, Luigi; Southworth, John; Greenberg, Adam; Turner, Jake D; Thompson, Robert; Taylor, Brian W; Levine, Stephen E; Webber, Matthew W

    2014-01-01

    It is important to explore the diversity of characteristics of low-mass, low-density planets to understand the nature and evolution of this class of planets. We present a homogeneous analysis of 12 new and 9 previously published broadband photometric observations of the Uranus-sized extrasolar planet GJ 3470b, which belongs to the growing sample of sub-Jovian bodies orbiting M dwarfs. The consistency of our analysis explains some of the discrepancies between previously published results and provides updated constraints on the planetary parameters. Our data are also consistent with previous transit observations of this system. We also provide new spectroscopic measurements of GJ~3470 from 0.33 to 2.42 $\\mu$$m$ to aid our analysis. We find $R_{\\star}$ = 0.48$\\pm$0.04 $R_{\\odot}$, $M_{\\star}$ = 0.51$\\pm$0.06 $M_{\\odot}$, and $T_{\\rm eff}$ = 3652$\\pm$50 K for GJ 3470, along with a rotation period of $20.70\\pm{0.15}$ d and an R-band amplitude of 0.01 mag, which is small enough that current transit measurements sho...

  16. Formation and X-ray Emission from Hot Bubbles in Planetary Nebulae. II. Hot bubble X-ray emission

    CERN Document Server

    Toalá, J A

    2016-01-01

    We present a study of the X-ray emission from numerical simulations of hot bubbles in planetary nebulae (PNe). High-resolution, two-dimensional, radiation-hydrodynamical simulations of the formation and evolution of hot bubbles in PNe, with and without thermal conduction, are used to calculate the X-ray emission and study its time-dependence and relationship to the changing stellar parameters. Instabilities in the wind-wind interaction zone produce clumps and filaments in the swept-up shell of nebular material. Turbulent mixing and thermal conduction at the corrugated interface can produce quantities of intermediate temperature and density gas between the hot, shocked wind bubble and the swept-up photoionized nebular material, which can emit in soft, diffuse X-rays. We use the CHIANTI software to compute synthetic spectra for the models and calculate their luminosities. We find that models both with conduction and those without can produce the X-ray temperatures and luminosities that are in the ranges reporte...

  17. Robo-AO Kepler Planetary Candidate Survey II: Adaptive Optics Imaging of 969 Kepler Exoplanet Candidate Host Stars

    CERN Document Server

    Baranec, Christoph; Law, Nicholas M; Morton, Tim; Riddle, Reed; Atkinson, Dani; Schonhut, Jessica; Crepp, Justin

    2016-01-01

    We initiated the Robo-AO Kepler Planetary Candidate Survey in 2012 to observe each Kepler exoplanet candidate host star with high-angular-resolution visible-light laser-adaptive-optics imaging. Our goal is to find nearby stars lying in Kepler's photometric apertures that are responsible for the relatively high probability of false-positive exoplanet detections and that cause underestimates of the size of transit radii. Our comprehensive survey will also shed light on the effects of stellar multiplicity on exoplanet properties and will identify rare exoplanetary architectures. In this second part of our ongoing survey, we observed an additional 969 Kepler planet candidate hosts and we report blended stellar companions up to $\\Delta m \\approx 6$ that contribute to Kepler's measured light curves. We found 203 companions within $\\sim$4" of 181 of the Kepler stars, of which 141 are new discoveries. We measure the nearby-star probability for this sample of Kepler planet candidate host stars to be 10.6% $\\pm$ 1.1% a...

  18. The population of planetary nebulae and H II regions in M 81. A study of radial metallicity gradients and chemical evolution

    Science.gov (United States)

    Stanghellini, L.; Magrini, L.; Villaver, E.; Galli, D.

    2010-10-01

    Context. M 81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations. Aims: We analyze the chemical abundances of planetary nebulae and H ii regions in the M 81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way. Methods: We acquired Hectospec/MMT spectra of 39 PNe and 20 H ii regions, with 33 spectra viable for temperature and abundance analysis. Our PN observations represent the first PN spectra in M 81 ever published, while several H ii region spectra have been published before, although without a direct electron temperature determination. We determine elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon in PNe and H ii regions, and determine their averages and radial gradients. Results: The average O/H ratio of PNe compared to that of the H ii regions indicates a general oxygen enrichment in M 81 in the last ~10 Gyr. The PN metallicity gradient in the disk of M 81 is Δlog(O/H)/ΔRG = -0.055 ± 0.02 dex/kpc. Neon and sulfur in PNe have a radial distribution similar to that of oxygen, with similar gradient slopes. If we combine our H ii sample with the one in the literature we find a possible mild evolution of the gradient slope, with results consistent with gradient steepening with time. Additional spectroscopy is needed to confirm this trend. There are no type I PNe in our M 81 sample, consistently with the observation of only the brightest bins of the PNLF, the galaxy metallicity, and the evolution of post-AGB shells. Conclusions: Both the young and the old populations of M 81 disclose shallow but detectable negative radial metallicity gradient, which could be slightly steeper for the young population, thus not excluding a mild gradients steepening with the time since galaxy formation. During its evolution M 81 has been producing oxygen; its total oxygen enrichment exceeds that of other nearby

  19. Robo-AO Kepler Planetary Candidate Survey. II. Adaptive Optics Imaging of 969 Kepler Exoplanet Candidate Host Stars

    Science.gov (United States)

    Baranec, Christoph; Ziegler, Carl; Law, Nicholas M.; Morton, Tim; Riddle, Reed; Atkinson, Dani; Schonhut, Jessica; Crepp, Justin

    2016-07-01

    We initiated the Robo-AO Kepler Planetary Candidate Survey in 2012 to observe each Kepler exoplanet candidate host star with high angular resolution, visible light, laser adaptive optics (AOs) imaging. Our goal is to find nearby stars lying in Kepler's photometric apertures that are responsible for the relatively high probability of false-positive exoplanet detections and that cause underestimates of the size of transit radii. Our comprehensive survey will also shed light on the effects of stellar multiplicity on exoplanet properties and will identify rare exoplanetary architectures. In this second part of our ongoing survey, we observed an additional 969 Kepler planet candidate hosts and we report blended stellar companions up to {{Δ }}m≈ 6 that contribute to Kepler's measured light curves. We found 203 companions within ˜4″ of 181 of the Kepler stars, of which 141 are new discoveries. We measure the nearby star probability for this sample of Kepler planet candidate host stars to be 10.6% ± 1.1% at angular separations up to 2.″5, significantly higher than the 7.4% ± 1.0% probability discovered in our initial sample of 715 stars; we find the probability increases to 17.6% ± 1.5% out to a separation of 4.″0. The median position of Kepler Objects of Interest (KOIs) observed in this survey are 1.°1 closer to the galactic plane, which may account for some of the nearby star probability enhancement. We additionally detail 50 Keck AO images of Robo-AO observed KOIs in order to confirm 37 companions detected at a <5σ significance level and to obtain additional infrared photometry on higher significance detected companions.

  20. XUV exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets II: Hydrogen coronae and ion escape

    CERN Document Server

    Kislyakova, K G; Holmström, M; Panchenko, M; Odert, P; Erkaev, N V; Leitzinger, M; Khodachenko, M L; Kulikov, Yu N; Güdel, M; Hanslmeier, A

    2012-01-01

    The interactions between the stellar wind plasma flow of a typical M star such as GJ 436 and hydrogen-rich upper atmospheres of an Earth-like planet and a "super-Earth" with the radius of 2 R_Earth and a mass of 10 M_Earth, located within the habitable zone at ~0.24 AU are studied. The formation of extended atomic hydrogen coronae under the influence of such factors as the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause) and the heating efficiency on the evolution of the hydrogen-rich upper atmospheres is investigated. XUV fluxes which are 1, 10, 50 and 100 times higher compared to that of the present Sun are considered and the formation of the high-energy neutral hydrogen clouds around the planets due to charge-exchange reaction under various stellar conditions have been modeled. Charge-exchange between stellar wind protons with the planetary hydrogen atoms and photoionization leads to the production of initially cold io...

  1. National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) Atmospheric Model Intercomparison Project (AMIP)-II Reanalysis (Reanalysis-2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NCEP-DOE Atmospheric Model Intercomparison Project (AMIP-II) reanalysis is a follow-on project to the "50-year" (1948-present) NCEP-NCAR Reanalysis Project....

  2. Detectability of planetary characteristics in disk-averaged spectra II: synthetic spectra and light-curves of earth.

    Science.gov (United States)

    Tinetti, Giovanna; Meadows, Victoria S; Crisp, David; Kiang, Nancy Y; Kahn, Brian H; Bosc, Emmanuel; Fishbein, Evan; Velusamy, Thangasamy; Turnbull, Margaret

    2006-12-01

    Spatially and spectrally resolved models were used to explore the observational sensitivity to changes in atmospheric and surface properties and the detectability of surface biosignatures in the globally averaged spectra and light-curves of the Earth. Compared with previous efforts to characterize the Earth using disk-averaged models, a more comprehensive and realistic treatment of the surface and atmosphere was taken into account here. Our results are presented as a function of viewing geometry and phases at both visible/near-infrared (0.5-1.7 microm) and mid-infrared (5-25 microm) wavelength ranges, applicable to the proposed NASA-Terrestrial Planet Finder visible coronagraph and mid-infrared interferometer and to the ESADarwin mission architectures. Clouds can change the thermal emission by as much as 50% compared with the cloud-free case and increase the visible albedo by up to 500% for completely overcast cases at the dichotomy phase. Depending on the observed phase and their distribution and type, clouds can also significantly alter the spectral shape. Moreover, clouds impact the detectability of surface biosignatures in the visible wavelength range. Modeling the disk-averaged sensitivity to the "red-edge," a distinctive spectral signature of vegetation, showed that Earth's land vegetation could be seen in disk-averaged spectra, even with cloud cover, when the signal was averaged over the daily time scale. We found that vegetation is more readily discriminated from clouds at dichotomy (50% illumination) rather than at full phase. The detectability of phytoplankton was also explored, but was found to be more difficult to detect in the disk-average than land vegetation.

  3. Planetary Rings

    Science.gov (United States)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  4. Strongly Interacting Planetary Systems

    Science.gov (United States)

    Ford, Eric

    2017-01-01

    Both ground-based Doppler surveys and NASA's Kepler mission have discovered a diversity of planetary system architectures that challenge theories of planet formation. Systems of tightly-packed or near-resonant planets are particularly useful for constraining theories of orbital migration and the excitation of orbital eccentricities and inclinations. In particular, transit timing variations (TTVs) provide a powerful tool to characterize the masses and orbits of dozens of small planets, including many planets at orbital periods beyond the reach of both current Doppler surveys and photoevaporation-induced atmospheric loss. Dynamical modeling of these systems has identified some ``supper-puffy'' planets, i.e., low mass planets with surprisingly large radii and low densities. I will describe a few particularly interesting planetary systems and discuss the implications for the formation of planets ranging from gaseous super-Earth-size planets to rocky planets the size of Mars.

  5. The effect of the 11-year solar-cycle on the temperature in the upper-stratosphere and mesosphere: Part II numerical simulations and the role of planetary waves

    Science.gov (United States)

    Hampson, J.; Keckhut, P.; Hauchecorne, A.; Chanin, M. L.

    2005-07-01

    Results from mechanistic model simulations have been analysed to examine the effect of the solar cycle, and in particular how the level of planetary wave activity changes the effect of the solar cycle. The model is a stratosphere and mesosphere model with detailed chemical, radiative and dynamical schemes. Planetary waves are initiated at the lowest boundary level of the model, which corresponds to the tropopause height. Model simulations have been carried out in pairs, with one simulation using solar forcing corresponding to solar minimum and the other to solar maximum. The level of lower boundary planetary wave forcing is varied between pairs of model simulations. The difference in temperature signal between the pairs of simulations is presented. The results illustrate the crucial role played by the planetary wave forcing in the solar cycle temperature signal. The solar cycle temperature signal in the tropics and subtropics is about 1 K for all values of wave forcing. However, in the extra-tropics the solar signal varies critically with wave forcing, giving a solar signal as strong as 16 K for intermediate values of wave forcing. Despite some spatial differences, the simulations with a specific wave forcing show good qualitative agreements with observational results presented in the companion paper [Keckhut et al., 2005. Journal of Atmospheric and Solar-Terrestrial Physics, submitted for publication]. Above a critical level of wave activity, the non-linear interaction with the mean flow induces a stratospheric warming and a strong temperature change. The critical wave-forcing amplitude necessary to produce such an event is very sensitive to the initial state of the atmosphere and a small change of the mean wind, due for example to an enhancement of the solar forcing, can generate a large difference in temperature, depending on the level of the wave forcing. The numerical simulations presented here suggest a mechanism by which a small change induced by the solar

  6. SPEX: The spectropolarimeter for planetary EXploration

    NARCIS (Netherlands)

    Snik, F.; Rietjens, J.H.H.; Harten, G. van; Stam, D.M.; Keller, C.U.; Smit, J.M.; Laan, E.C.; Verlaan, A.L.; Horst, R. ter; Navarro, R.; Wielinga, K.; Moon, S.G.; Voors, R.

    2010-01-01

    SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, compact instrument for spectropolarimetry, and in particular for detecting and characterizing aerosols in planetary atmospheres. With its ∼1-liter volume it is capable of full linear spectropolarimetry, without moving parts. The d

  7. SPEX: The spectropolarimeter for planetary EXploration

    NARCIS (Netherlands)

    Snik, F.; Rietjens, J.H.H.; Harten, G. van; Stam, D.M.; Keller, C.U.; Smit, J.M.; Laan, E.C.; Verlaan, A.L.; Horst, R. ter; Navarro, R.; Wielinga, K.; Moon, S.G.; Voors, R.

    2010-01-01

    SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, compact instrument for spectropolarimetry, and in particular for detecting and characterizing aerosols in planetary atmospheres. With its ∼1-liter volume it is capable of full linear spectropolarimetry, without moving parts. The d

  8. Astrophysical Conditions for Planetary Habitability

    CERN Document Server

    Guedel, M; Erkaev, N; Kasting, J; Khodachenko, M; Lammer, H; Pilat-Lohinger, E; Rauer, H; Ribas, I; Wood, B E

    2014-01-01

    With the discovery of hundreds of exoplanets and a potentially huge number of Earth-like planets waiting to be discovered, the conditions for their habitability have become a focal point in exoplanetary research. The classical picture of habitable zones primarily relies on the stellar flux allowing liquid water to exist on the surface of an Earth-like planet with a suitable atmosphere. However, numerous further stellar and planetary properties constrain habitability. Apart from "geophysical" processes depending on the internal structure and composition of a planet, a complex array of astrophysical factors additionally determine habitability. Among these, variable stellar UV, EUV, and X-ray radiation, stellar and interplanetary magnetic fields, ionized winds, and energetic particles control the constitution of upper planetary atmospheres and their physical and chemical evolution. Short- and long-term stellar variability necessitates full time-dependent studies to understand planetary habitability at any point ...

  9. Planetary Society

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Carl Sagan, Bruce Murray and Louis Friedman founded the non-profit Planetary Society in 1979 to advance the exploration of the solar system and to continue the search for extraterrestrial life. The Society has its headquarters in Pasadena, California, but is international in scope, with 100 000 members worldwide, making it the largest space interest group in the world. The Society funds a var...

  10. Planetary Rings

    CERN Document Server

    Tiscareno, Matthew S

    2011-01-01

    Planetary rings are the only nearby astrophysical disks, and the only disks that have been investigated by spacecraft. Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 1e-7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close-range and in real-time in planetary rings. We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The main rings of Saturn comprise our system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty...

  11. Environmental consequences of uranium atmospheric releases from fuel cycle facility: II. The atmospheric deposition of uranium and thorium on plants.

    Science.gov (United States)

    Pourcelot, L; Masson, O; Renaud, P; Cagnat, X; Boulet, B; Cariou, N; De Vismes-Ott, A

    2015-03-01

    Uranium and thorium isotopes were measured in cypress leaves, wheat grains and lettuce taken in the surroundings of the uranium conversion facility of Malvési (South of France). The comparison of activity levels and activity ratios (namely (238)U/(232)Th and (230)Th/(232)Th) in plants with those in aerosols taken at this site and plants taken far from it shows that aerosols emitted by the nuclear site (uranium releases in the atmosphere by stacks and (230)Th-rich particles emitted from artificial ponds collecting radioactive waste mud) accounts for the high activities recorded in the plant samples close to the site. The atmospheric deposition process onto the plants appears to be the dominant process in plant contamination. Dry deposition velocities of airborne uranium and thorium were measured as 4.6 × 10(-3) and 5.0 × 10(-3) m s(-1), respectively.

  12. Wave activity (planetary, tidal) throughout the middle atmosphere (20-100km) over the CUJO network: Satellite (TOMS) and Medium Frequency (MF) radar observations

    OpenAIRE

    Manson, A. H.; Meek, C. E.; Chshyolkova, T.; Avery, S. K.; Thorsen, D.; MacDougall, J.W.; Hocking, W.; Murayama, Y.; Igarashi, K

    2005-01-01

    Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT) is studied using combinations of ground-based (GB) and satellite instruments (2000-2002). The relatively new MFR (medium frequency radar) at Platteville (40° N, 105° W) has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opp...

  13. A mobile polar atmospheric parameter measurement system:II. First atmospheric turbulence observation at Antarctic Taishan Station

    Institute of Scientific and Technical Information of China (English)

    TIAN Qiguo; JIANG Peng; WU Xiaoqing; JIN Xinmiao; LU Shan; JI Tuo; CHAI Bo; ZHANG Shaohua; ZHOU Hongyan

    2015-01-01

    This is the second paper of a series devoted to atmospheric optical turbulence Cn2 observation using a mobile polar atmospheric parameter measurement system. We present the initial results of Cn2 measurement at Antarctic Taishan Station using micro-thermal sensors and a three-dimensional sonic anemometer at height ~2.0 m above the snow surface. The site testing experiments were carried out during the 30th Chinese National Antarctic Research Expedition (CHINARE). We collected about 1 000 h of data between 30 December 2013 and 10 February 2014. The Cn2 curve exhibits clear daily structures, with two peaks around midnight and midday and two troughs around 7:30 and 17:00 local time (UTC+5). The mean Cn2 is 2.7×10−15 m−2/3 and the 25th and 75th percentiles of the Cn2 cumulative distribution are 9.6×10−16 m−2/3 and 6.2×10−15 m−2/3, respectively. Meteorological parameters such as temperature, relative humidity, wind speed, and air pressure are also presented.

  14. The rigid shell component for superrotation in planetary atmospheres: Angular momentum budget, mechanical analog and simulation of the spin up process

    Science.gov (United States)

    Mayr, H. G.; Harris, I.

    1981-01-01

    An analysis of superrotation in the atmosphere of planets, with rotation axis perpendicular to the orbital plane is presented. As the atmosphere expands, Hadley cells develop producing a redistribution of mass and angular momentum. A three dimensional thermally driven zonally symmetric spectral model and Laplace transformation simulate the time evolution of a fluid leading from corotation under globally uniform heating to superrotation under globally nonuniform heating. For high viscosities the rigid shell component of atmospheric superrotation can be understood in analogy with a pirouette. During spin up angular momentum is transferred to the planet. For low iscosities, the process is reversed. A tendency toward geostrophy, combined with increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. Resultant viscous shear near the surface permits angular momentum to flow from the planet into the atmosphere propagating upwards to produce high altitude superrotation rates.

  15. Ultraviolet C II and Si III Transit Spectroscopy and Modeling of the Evaporating Atmosphere of GJ436b

    Science.gov (United States)

    Parke Loyd, R. O.; Koskinen, T. T.; France, Kevin; Schneider, Christian; Redfield, Seth

    2017-01-01

    Hydrogen gas evaporating from the atmosphere of the hot-Neptune GJ436b absorbs over 50% of the stellar Lyα emission during transit. Given the planet’s atmospheric composition and energy-limited escape rate, this hydrogen outflow is expected to entrain heavier atoms such as C and O. We searched for C and Si in the escaping atmosphere of GJ436b using far-ultraviolet Hubble Space Telescope COS G130M observations made during the planet’s extended H i transit. These observations show no transit absorption in the C ii 1334,1335 Å and Si iii 1206 Å lines integrated over [‑100, 100] km s‑1, imposing 95% (2σ) upper limits of 14% (C ii) and 60% (Si iii) depth on the transit of an opaque disk and 22% (C ii) and 49% (Si iii) depth on an extended highly asymmetric transit similar to that of H i Lyα. C+ is likely present in the outflow according to a simulation we carried out using a spherically symmetric photochemical-hydrodynamical model. This simulation predicts an ∼2% transit over the integrated bandpass, consistent with the data. At line center, we predict the C ii transit depth to be as high as 19%. Our model predicts a neutral hydrogen escape rate of 1.6× {10}9 g s‑1 (3.1× {10}9 g s‑1 for all species) for an upper atmosphere composed of hydrogen and helium.

  16. Planetary Systems and the Origins of Life

    Science.gov (United States)

    Pudritz, Ralph; Higgs, Paul; Stone, Jonathon

    2013-01-01

    Preface; Part I. Planetary Systems and the Origins of Life: 1. Observations of extrasolar planetary systems Shay Zucker; 2. The atmospheres of extrasolar planets L. Jeremy Richardson and Sara Seager; 3. Terrestrial planet formation Edward Thommes; 4. Protoplanetary disks, amino acids and the genetic code Paul Higgs and Ralph Pudritz; 5. Emergent phenomena in biology: the origin of cellular life David Deamer; Part II. Life on Earth: 6. Extremophiles: defining the envelope for the search for life in the Universe Lynn Rothschild; 7. Hyperthermophilic life on Earth - and on Mars? Karl Stetter; 8. Phylogenomics: how far back in the past can we go? Henner Brinkmann, Denis Baurain and Hervé Philippe; 9. Horizontal gene transfer, gene histories and the root of the tree of life Olga Zhaxybayeva and J. Peter Gogarten; 10. Evolutionary innovation versus ecological incumbency Adolf Seilacher; 11. Gradual origins for the Metazoans Alexandra Pontefract and Jonathan Stone; Part III. Life in the Solar System?: 12. The search for life on Mars Chris McKay; 13. Life in the dark dune spots of Mars: a testable hypothesis Eörs Szathmary, Tibor Ganti, Tamas Pocs, Andras Horvath, Akos Kereszturi, Szaniszlo Berzci and Andras Sik; 14. Titan: a new astrobiological vision from the Cassini-Huygens data François Raulin; 15. Europa, the Ocean Moon: tides, permeable ice, and life Richard Greenberg; Index.

  17. Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters

    NARCIS (Netherlands)

    Cenarro, A. J.; Peletier, R. F.; Sanchez-Blazquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcon-Barroso, J.; Gorgas, J.; Jimenez-Vicente, J.; Vazdekis, A.

    2007-01-01

    We present a homogeneous set of stellar atmospheric parameters (T-eff, log g, [Fe/H]) for MILES, a new spectral stellar library covering the range lambda lambda 3525-7500 angstrom at 2.3 angstrom (FWHM) spectral resolution. The library consists of 985 stars spanning a large range in atmospheric para

  18. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-08-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  19. Modelled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-11-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long-range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present-day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparison. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modelled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  20. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Directory of Open Access Journals (Sweden)

    B. H. Samset

    2014-08-01

    Full Text Available Atmospheric black carbon (BC absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF. However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  1. XUV-exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part II: hydrogen coronae and ion escape.

    Science.gov (United States)

    Kislyakova, Kristina G; Lammer, Helmut; Holmström, Mats; Panchenko, Mykhaylo; Odert, Petra; Erkaev, Nikolai V; Leitzinger, Martin; Khodachenko, Maxim L; Kulikov, Yuri N; Güdel, Manuel; Hanslmeier, Arnold

    2013-11-01

    We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R(Earth) and a mass of 10 M(Earth), located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×10²⁵ s⁻¹ to ∼5.3×10³⁰ s⁻¹, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EO(H)) to <3 EO(H) and usually is several times smaller in comparison to the thermal atmospheric escape rates.

  2. Solar Variability and Planetary Climates

    CERN Document Server

    Calisesi, Y; Gray, L; Langen, J; Lockwood, M

    2007-01-01

    Variations in solar activity, as revealed by variations in the number of sunspots, have been observed since ancient times. To what extent changes in the solar output may affect planetary climates, though, remains today more than ever a subject of controversy. In 2000, the SSSI volume on Solar Variability and Climate reviewed the to-date understanding of the physics of solar variability and of the associated climate response. The present volume on Solar Variability and Planetary Climates provides an overview of recent advances in this field, with particular focus at the Earth's middle and lower atmosphere. The book structure mirrors that of the ISSI workshop held in Bern in June 2005, the collection of invited workshop contributions and of complementary introductory papers synthesizing the current understanding in key research areas such as middle atmospheric processes, stratosphere-troposphere dynamical coupling, tropospheric aerosols chemistry, solar storm influences, solar variability physics, and terrestri...

  3. Relationship between variability of the semidiurnal tide in the Northern Hemisphere mesosphere and quasi-stationary planetary waves throughout the global middle atmosphere

    Directory of Open Access Journals (Sweden)

    X. Xu

    2009-11-01

    Full Text Available To investigate possible couplings between planetary waves and the semidiurnal tide (SDT, this work examines the statistical correlations between the SDT amplitudes observed in the Northern Hemisphere (NH mesosphere and stationary planetary wave (SPW with wavenumber S=1 (SPW1 amplitudes throughout the global stratosphere and mesosphere. The latter are derived from the Aura-MLS temperature measurements. During NH summer-fall (July–October, the mesospheric SDT amplitudes observed at Svalbard (78° N and Eureka (80° N usually do not show persistent correlations with the SPW1 amplitudes in the opposite hemisphere. Although the SDT amplitudes observed at lower latitudes (~50–70° N, especially at Saskatoon (52° N, are often shown to be highly and positively correlated with the SPW1 amplitudes in high southern latitudes, these correlations cannot be sufficiently explained as evidence for a direct physical link between the Southern Hemisphere (SH winter-early spring SPW and NH summer-early fall mesospheric SDT. This is because the migrating tide's contribution is usually dominant in the mid-high latitude (~50–70° N NH mesosphere during the local late summer-early fall (July–September. The numerical correlation is dominated by similar low-frequency variability or trends between the amplitudes of the NH SDT and SH SPW1 during the respective equinoctial transitions. In contradistinction, during NH winter (November–February, the mesospheric SDT amplitudes at northern mid-high latitudes (~50–80° N are observed to be significantly and positively correlated with the SPW1 amplitudes in the same hemisphere in most cases. Because both the SPW and migrating SDT are large in the NH during the local winter, a non-linear interaction between SPW and migrating SDT probably occurs, thus providing a global non-migrating SDT. This is consistent with observations of SDT in Antarctica that are large in summer than in winter. It is suggested that

  4. ANALYTICAL SOLUTION FOR WAVES IN PLANETS WITH ATMOSPHERIC SUPERROTATION. II. LAMB, SURFACE, AND CENTRIFUGAL WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, J.; López-Valverde, M. A. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Imamura, T. [Institute of Space and Astronautical Science-Japan Aerospace Exploration Agency 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Read, P. L. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford (United Kingdom); Luz, D. [Centro de Astronomia e Astrofísica da Universidade de Lisboa (CAAUL), Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa (Portugal); Piccialli, A., E-mail: peralta@iaa.es [LATMOS, UVSQ, 11 bd dAlembert, 78280 Guyancourt (France)

    2014-07-01

    This paper is the second in a two-part study devoted to developing tools for a systematic classification of the wide variety of atmospheric waves expected on slowly rotating planets with atmospheric superrotation. Starting with the primitive equations for a cyclostrophic regime, we have deduced the analytical solution for the possible waves, simultaneously including the effect of the metric terms for the centrifugal force and the meridional shear of the background wind. In those cases where the conditions for the method of the multiple scales in height are met, these wave solutions are also valid when vertical shear of the background wind is present. A total of six types of waves have been found and their properties were characterized in terms of the corresponding dispersion relations and wave structures. In this second part, we study the waves' solutions when several atmospheric approximations are applied: Lamb, surface, and centrifugal waves. Lamb and surface waves are found to be quite similar to those in a geostrophic regime. By contrast, centrifugal waves turn out to be a special case of Rossby waves that arise in atmospheres in cyclostrophic balance. Finally, we use our results to identify the nature of the waves behind atmospheric periodicities found in polar and lower latitudes of Venus's atmosphere.

  5. Planetary fertility during the past 400 ka based on the triple isotope composition of atmospheric oxygen in trapped gases from the Vostok ice core

    Science.gov (United States)

    Blunier, T.; Bender, M. L.; Barnett, B.; von Fisher, J. C.

    2012-04-01

    The productivity of the biosphere leaves its imprint on the isotopic composition of atmospheric oxygen. Ultimately atmospheric oxygen, through photosynthesis, originates from seawater. Fractionations during the passage from seawater to atmospheric O2 and during respiration are mass dependent, affecting δ17O about half as much as δ18O. An "anomalous" (also termed mass independent) fractionation process changes δ17O about 1.7 times as much as δ18O during isotope exchange between O2 and CO2 in the stratosphere. The relative rates of biological O2 production and stratospheric processing determine the relationship between δ17O and δ18O of O2 in the atmosphere. Variations of this relationship thus allow us to estimate changes in the rate of mass dependent O2 production by photosynthesis versus the rate of mass independent O2-CO2 exchange in the stratosphere. However, the analysis of the 17O anomaly is complicated because each hydrological and biological process influencing δ17O and δ18O fractionates 17O and 18O in slightly different proportions. In this study we present oxygen data covering the last 400 kyr from the Vostok ice core. We reconstruct oxygen productivities from the triple isotope composition of atmospheric oxygen with a box model. Our steady state model for the oxygen cycle takes into account fractionation during photosynthesis and respiration of the land and ocean biosphere as well as fractionation when oxygen passes through the stratosphere. We consider changes of fractionation factors linked to climate variations taking into account the span of estimates of the main factors affecting our calculations. We find that ocean oxygen productivity was likely elevated relative to modern during glacials. However, this increase probably did not fully compensate for a reduction in land ocean productivity resulting in a slight reduction in total oxygen production during glacials.

  6. Grain opacity and the bulk composition of extrasolar planets. II. An analytical model for the grain opacity in protoplanetary atmospheres

    CERN Document Server

    Mordasini, C

    2014-01-01

    Context. We investigate the grain opacity k_gr in the atmosphere of protoplanets. This is important for the planetary mass-radius relation since k_gr affects the H/He envelope mass of low-mass planets and the critical core mass of giant planets. Aims. The goal of this study is to derive an analytical model for k_gr. Methods. Our model is based on the comparison of the timescales of microphysical processes like grain settling in the Stokes and Epstein regime, growth by Brownian motion coagulation and differential settling, grain evaporation, and grain advection due to envelope contraction. With these timescales we derive the grain size, abundance, and opacity. Results. We find that the main growth process is differential settling. In this regime, k_gr has a simple functional form and is given as 27 Q/8 H rho in the Epstein regime and as 2 Q/H rho for Stokes drag. Grain dynamics lead to a typical radial structure of k_gr with high ISM-like values in the top layers but a strong decrease in the deeper parts where...

  7. Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II

    CERN Document Server

    Mitsuka, G; Hayato, Y; Iida, T; Ikeda, M; Kameda, J; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Hazama, S; Higuchi, I; Ishihara, C; Kaji, H; Kajita, T; Kaneyuki, K; Nishino, H; Okumura, K; Tanimoto, N; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Bays, K; Cravens, J P; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Vagins, M R; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J; Scholberg, K; Walter, C W; Wendell, R; Ishizuka, T; Tasaka, S; Learned, J G; Matsuno, S; Watanabe, Y; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Yokoyama, M; Fukuda, Y; Itow, Y; Tanaka, T; Jung, C K; Lopez, G; McGrew, C; Yanagisawa, C; Tamura, N; Idehara, Y; Sakuda, M; Kuno, Y; Yoshida, M; Kim, S B; Yang, B S; Okazawa, H; Choi, Y; Seo, H K; Furuse, Y; Nishijima, K; Yokosawa, Y; Koshiba, M; Totsuka, Y; Chen, S; Liu, J; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Connolly, K; Thrane, E; Wilkes, R J

    2011-01-01

    In this paper we study non-standard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton non-universality (NU) and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x 10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a function of the NU coupling, varepsilon_{e e}. We find no evidence of non-standard neutrino interactions in the Super-Kamiokande atmospheric data.

  8. Hypersonic and planetary entry flight mechanics

    Science.gov (United States)

    Vinh, N. X.; Busemann, A.; Culp, R. D.

    1980-01-01

    The book treats hypersonic flight trajectories and atmospheric entry flight mechanics in light of their importance for space shuttle entry. Following a review of the structures of planetary atmospheres and aerodynamic forces, equations are derived for flight over a spherical planet, and the performance of long-range hypervelocity vehicles in extra-atmospheric flight is analyzed. Consideration is then given to vehicle trajectories in the powered and atmospheric reentry phases of flight, and several first-order solutions are derived for various planetary entry situations. The second-order theory of Loh for entry trajectories is presented along with the classical theories of Yaroshevskii and Chapman for entry into planetary atmospheres, and the thermal problems encountered in hypersonic flight are analyzed. A unified theory for entry into planetary atmospheres is then introduced which allows the performance of a general type of lifting vehicle to be studied, and applied to the analysis of orbit contraction due to atmospheric drag, flight with lift modulation and lateral maneuvers.

  9. Planetary Data Archiving Activities of ISRO

    Science.gov (United States)

    Gopala Krishna, Barla; D, Rao J.; Thakkar, Navita; Prashar, Ajay; Manthira Moorthi, S.

    composition & mineralogy of mars, Mars Exospheric Neutral Composition Analyser (MENCA) to study the composition and density of the Martian neutral atmosphere and Lyman Alpha Photometer (LAP) to investigate the loss process of water in Martian atmosphere, towards fulfilling the mission objectives. Active archive created in PDS for some of the instrument data during the earth phase of the mission is being analysed by the PIs. The Mars science data from the onboard instruments is expected during September 2014. The next planetary mission planned to moon is Chandrayaan-2 which consists of an orbiter having five instruments (http://www.isro.org) viz, (i) Imaging IR Spectrometer (IIRS) for mineral mapping, (ii) TMC-2 for topographic mapping, (iii) MiniSAR to detect water ice in the permanently shadowed regions on the Lunar poles, up to a depth of a few meters, (iv) Large Area Soft X-ray spectrometer (CLASS) & Solar X-ray Monitor (XSM) for mapping the major elements present on the lunar surface and (v)Neutral Mass Spectrometer (ChACE2) to carry out a detailed study of the lunar exosphere towards moon exploration; a rover for some specific experiments and a Lander for technology experiment and demonstration. The data is planned to be archived in PDS standards.

  10. Millimagnitude Photometry for Transiting Extrasolar Planetary Candidates: II. Transits of OGLE-TR-113-b in the Optical and Near-IR

    CERN Document Server

    Díaz, Rodrigo F; Fernández, José Miguel; Gallardo, José; Gieren, Wolfgang; Ivanov, Valentin D; Mauas, Pablo; Minniti, Dante; Pietrzynski, Grzegorz; Pérez, Felipe; Ruíz, María Teresa; Udalski, Andrzej; Zoccali, Manuela

    2007-01-01

    We present precise V and Ks-band transit photometry for the planetary host star OGLE-TR-113. Using the Ks-band photometry, we confirm the dwarf nature of OGLE-TR-113, and obtain new estimates for its effective temperature, distance and reddening. We employ the V-band photometry to obtain planetary and orbit parameters from the transit fit, a= (0.0232 \\pm 0.0038) AU, orbital period P= (1.4324752 \\pm 0.0000015) days, i= 86.7 - 90, R_p= (1.09 \\pm 0.09) R_J. These values are in excellent agreement with previous works. Assuming a mass M_p= (1.32 \\pm 0.19) M_J for the planet we obtain its mean density \\rho= (1.26 \\pm 0.50) g cm^{-3}, also in agreement with previous works. The transit observed in the Ks-band has a larger scatter and we find its amplitude to be consistent with that in the V-band. In this way, we find an independent confirmation of the planetary nature of OGLE-TR-113b.

  11. Bacillus subtilis spore survival and expression of germination-induced bioluminescence after prolonged incubation under simulated Mars atmospheric pressure and composition: implications for planetary protection and lithopanspermia

    Science.gov (United States)

    Nicholson, Wayne L.; Schuerger, Andrew C.

    2005-01-01

    Bacterial endospores in the genus Bacillus are considered good models for studying interplanetary transfer of microbes by natural or human processes. Although spore survival during transfer itself has been the subject of considerable study, the fate of spores in extraterrestrial environments has received less attention. In this report we subjected spores of a strain of Bacillus subtilis, containing luciferase resulting from expression of an sspB-luxAB gene fusion, to simulated martian atmospheric pressure (7-18 mbar) and composition (100% CO(2)) for up to 19 days in a Mars simulation chamber. We report here that survival was similar between spores exposed to Earth conditions and spores exposed up to 19 days to simulated martian conditions. However, germination-induced bioluminescence was lower in spores exposed to simulated martian atmosphere, which suggests sublethal impairment of some endogenous spore germination processes.

  12. Atmospheres and Spectra of Strongly Magnetized Neutron Stars II Effect of Vacuum Polarization

    CERN Document Server

    Ho, W C G; Ho, Wynn C. G.; Lai, Dong

    2003-01-01

    We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B=10^14-10^15 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy that depends on the plasma density. Vacuum polarization can also induce resonant conversion of photon modes via a mechanism analogous to the MSW mechanism for neutrino oscillation. We construct atmosphere models in radiative equilibrium with an effective temperature of a few \\times 10^6 K by solving the full radiative transport equations for both polarization modes in a fully ionized hydrogen plasma. We discuss the subtleties in treating the vacuum polarization effects in the atmosphere models and present approximate solutions to the radiative transfer problem which bracket the true answer. We show from both analytic considerations and numerical calculatio...

  13. Distances from Planetary Nebulae

    CERN Document Server

    Ciardullo, R

    2003-01-01

    The [O III] 5007 planetary nebula luminosity function (PNLF) occupies an important place on the extragalactic distance ladder. Since it is the only method that is applicable to all the large galaxies of the Local Supercluster, it is uniquely useful for cross-checking results and linking the Population I and Population II distance scales. We review the physics underlying the method, demonstrate its precision, and illustrate its value by comparing its distances to distances obtained from Cepheids and the Surface Brightness Fluctuation (SBF) method. We use the Cepheid and PNLF distances to 13 galaxies to show that the metallicity dependence of the PNLF cutoff is in excellent agreement with that predicted from theory, and that no additional systematic corrections are needed for either method. However, when we compare the Cepheid-calibrated PNLF distance scale with the Cepheid-calibrated SBF distance scale, we find a significant offset: although the relative distances of both methods are in excellent agreement, th...

  14. Small-scale topology of solar atmosphere dynamics : II : granulation, K2v grains and waves

    NARCIS (Netherlands)

    Hoekzema, N.M.; Rutten, R.J.

    1997-01-01

    We continue studying the small-scale topology of dynamical phenomena in the quiet-sun internetwork atmosphere throug statistical estimation of the co-location probability of different fine-structure elements and wave modes.In this paper we chart spatial alignments between the granular brig tness st

  15. Small-scale topology of solar atmosphere dynamics : II : granulation, K2v grains and waves

    NARCIS (Netherlands)

    Hoekzema, N.M.; Rutten, R.J.

    2001-01-01

    We continue studying the small-scale topology of dynamical phenomena in the quiet-sun internetwork atmosphere throug statistical estimation of the co-location probability of different fine-structure elements and wave modes.In this paper we chart spatial alignments between the granular brig tness st

  16. Europlanet Research Infrastructure: Planetary Simulation Facilities

    Science.gov (United States)

    Davies, G. R.; Mason, N. J.; Green, S.; Gómez, F.; Prieto, O.; Helbert, J.; Colangeli, L.; Srama, R.; Grande, M.; Merrison, J.

    2008-09-01

    EuroPlanet The Europlanet Research Infrastructure consortium funded under FP7 aims to provide the EU Planetary Science community greater access for to research infrastructure. A series of networking and outreach initiatives will be complimented by joint research activities and the formation of three Trans National Access distributed service laboratories (TNA's) to provide a unique and comprehensive set of analogue field sites, laboratory simulation facilities, and extraterrestrial sample analysis tools. Here we report on the infrastructure that comprises the second TNA; Planetary Simulation Facilities. 11 laboratory based facilities are able to recreate the conditions found in the atmospheres and on the surfaces of planetary systems with specific emphasis on Martian, Titan and Europa analogues. The strategy has been to offer some overlap in capabilities to ensure access to the highest number of users and to allow for progressive and efficient development strategies. For example initial testing of mobility capability prior to the step wise development within planetary atmospheres that can be made progressively more hostile through the introduction of extreme temperatures, radiation, wind and dust. Europlanet Research Infrastructure Facilties: Mars atmosphere simulation chambers at VUA and OU These relatively large chambers (up to 1 x 0.5 x 0.5 m) simulate Martian atmospheric conditions and the dual cooling options at VUA allows stabilised instrument temperatures while the remainder of the sample chamber can be varied between 220K and 350K. Researchers can therefore assess analytical protocols for instruments operating on Mars; e.g. effect of pCO2, temperature and material (e.g., ± ice) on spectroscopic and laser ablation techniques while monitoring the performance of detection technologies such as CCD at low T & variable p H2O & pCO2. Titan atmosphere and surface simulation chamber at OU The chamber simulates Titan's atmospheric composition under a range of

  17. CO-SPATIAL LONG-SLIT UV/OPTICAL SPECTRA OF TEN GALACTIC PLANETARY NEBULAE WITH HST/STIS. II. NEBULAR MODELS, CENTRAL STAR PROPERTIES, AND He+CNO SYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Henry, R. B. C.; Miller, T. R. [Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Dufour, R. J. [Department of Space Physics and Astronomy, Rice University, Houston, TX 77251 (United States); Kwitter, K. B. [Department of Astronomy, Williams College, Williamstown, MA 01267 (United States); Shaw, R. A. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Buell, J. F. [SUNY College of Technology at Alfred, Alfred, NY 14843 (United States); Corradi, R. L. M. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

    2015-11-10

    The goal of the present study is twofold. First, we employ new HST/STIS spectra and photoionization modeling techniques to determine the progenitor masses of eight planetary nebulae (IC 2165, IC 3568, NGC 2440, NGC 3242, NGC 5315, NGC 5882, NGC 7662, and PB 6). Second, for the first time we are able to compare each object’s observed nebular abundances of helium, carbon, and nitrogen with abundance predictions of these same elements by a stellar model that is consistent with each object’s progenitor mass. Important results include the following: (1) the mass range of our objects’ central stars matches well with the mass distribution of other central stars of planetary nebulae and white dwarfs; (2) He/H is above solar in all of our objects, in most cases likely due to the predicted effects of first dredge-up; (3) most of our objects show negligible C enrichment, probably because their low masses preclude third dredge-up; (4) C/O versus O/H for our objects appears to be inversely correlated, which is perhaps consistent with the conclusion of theorists that the extent of atmospheric carbon enrichment from first dredge-up is sensitive to a parameter whose value increases as metallicity declines; (5) stellar model predictions of nebular C and N enrichment are consistent with observed abundances for progenitor star masses ≤1.5 M{sub ⊙}. Finally, we present the first published photoionization models of NGC 5315 and NGC 5882.

  18. Planetary Landscape Geography

    Science.gov (United States)

    Hargitai, H.

    INTRODUCTION Landscape is one of the most often used category in physical ge- ography. The term "landshap" was introduced by Dutch painters in the 15-16th cen- tury. [1] The elements that build up a landscape (or environment) on Earth consists of natural (biogenic and abiogenic - lithologic, atmospheric, hydrologic) and artificial (antropogenic) factors. Landscape is a complex system of these different elements. The same lithology makes different landscapes under different climatic conditions. If the same conditions are present, the same landscape type will appear. Landscapes build up a hierarchic system and cover the whole surface. On Earth, landscapes can be classified and qualified according to their characteristics: relief forms (morphology), and its potential economic value. Aesthetic and subjective parameters can also be considered. Using the data from landers and data from orbiters we can now classify planetary landscapes (these can be used as geologic mapping units as well). By looking at a unknown landscape, we can determine the processes that created it and its development history. This was the case in the Pathfinder/Sojourner panoramas. [2]. DISCUSSION Planetary landscape evolution. We can draw a raw landscape develop- ment history by adding the different landscape building elements to each other. This has a strong connection with the planet's thermal evolution (age of the planet or the present surface materials) and with orbital parameters (distance from the central star, orbit excentricity etc). This way we can build a complex system in which we use differ- ent evolutional stages of lithologic, atmospheric, hydrologic and biogenic conditions which determine the given - Solar System or exoplanetary - landscape. Landscape elements. "Simple" landscapes can be found on asteroids: no linear horizon is present (not differentiated body, only impact structures), no atmosphere (therefore no atmospheric scattering - black sky as part of the landscape) and no

  19. Planetary Data System (PDS)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Planetary Data System (PDS) is an archive of data products from NASA planetary missions, which is sponsored by NASA's Science Mission Directorate. We actively...

  20. Atmospheric circulation of tidally locked exoplanets II: dual-band radiative transfer and convective adjustment

    CERN Document Server

    Heng, Kevin; Phillipps, Peter J

    2011-01-01

    Improving upon our purely dynamical work, we present three-dimensional simulations of the atmospheric circulation on Earth-like (exo)planets and hot Jupiters using the GFDL-Princeton Flexible Modeling System (FMS). As the first steps away from the purely dynamical benchmarks of Heng, Menou & Phillipps (2011), we add dual-band radiative transfer and dry convective adjustment schemes to our computational setup. Our treatment of radiative transfer assumes stellar irradiation to peak at a wavelength shorter than and distinct from that at which the exoplanet re-emits radiation ("shortwave" versus "longwave"), and also uses a two-stream approximation. Convection is mimicked by adjusting unstable lapse rates to the dry adiabat. The bottom of the atmosphere is bounded by an uniform slab with a finite thermal inertia. For our hot Jupiter models, we include an analytical formalism for calculating temperature-pressure profiles, in radiative equilibrium, which accounts for the effect of collision-induced absorption v...

  1. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II ? reactions of organic species

    OpenAIRE

    2005-01-01

    International audience; This article, the second in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Organic species, which were last published in 1999, and were updated on the IUPAC website in late 2002. The article consists of a summary sheet, containing the recommended kinetic parameters for the evaluated reactions, and eight appendices con...

  2. Simulating Atmospheric Free-Space Optical Propagation; Part II: Haze, Fog, and Low Clouds Attenuations

    Science.gov (United States)

    Achour, Maha

    2002-12-01

    One of the biggest challenges facing Free-Space Optics deployment is proper understanding of optical signal propagation in different atmospheric conditions. In an earlier study by the author (30), attenuation by rain was analyzed and successfully modeled for infrared signal transmission. In this paper, we focus on attenuation due to scattering by haze, fog and low clouds droplets using the original Mie Scattering theory. Relying on published experimental results on infrared propagation, electromagnetic waves scattering by spherical droplet, atmospheric physics and thermodynamics, UlmTech developed a computer-based platform, Simulight, which simulates infrared signal (750 nm-12 μm) propagation in haze, fog, low clouds, rain and clear weather. Optical signals are scattered by fog droplets during transmission in the forward direction preventing the receiver from detecting the minimum required power. Weather databases describe foggy conditions by measuring the visibility parameter, which is, in general, defined as the maximum distance that the visible 550 nm signal can travel while distinguishing between the target object and its background at 2% contrast. Extrapolating optical signal attenuations beyond 550 nm using only visibility is not as straightforward as stated by the Kruse equation which is unfortunately widely used. We conclude that it is essential to understand atmospheric droplet sizes and their distributions based on measured attenuations to effectively estimate infrared attenuation. We focus on three types of popular fogs: Evolving, Stable and Selective.

  3. Magnetohydrostatic Equilibrium. II. Three-dimensional Multiple Open Magnetic Flux Tubes in the Stratified Solar Atmosphere

    Science.gov (United States)

    Gent, F. A.; Fedun, V.; Erdélyi, R.

    2014-07-01

    A system of multiple open magnetic flux tubes spanning the solar photosphere and lower corona is modeled analytically, within a realistic stratified atmosphere subject to solar gravity. This extends results for a single magnetic flux tube in magnetohydrostatic equilibrium, described in Gent et al. Self-similar magnetic flux tubes are combined to form magnetic structures, which are consistent with high-resolution observations. The observational evidence supports the existence of strands of open flux tubes and loops persisting in a relatively steady state. Self-similar magnetic flux tubes, for which an analytic solution to the plasma density and pressure distribution is possible, are combined. We calculate the appropriate balancing forces, applying to the equations of momentum and energy conservation to preserve equilibrium. Multiplex flux tube configurations are observed to remain relatively stable for up to a day or more, and it is our aim to apply our model as the background condition for numerical studies of energy transport mechanisms from the solar surface to the corona. We apply magnetic field strength, plasma density, pressure, and temperature distributions consistent with observational and theoretical estimates for the lower solar atmosphere. Although each flux tube is identical in construction apart from the location of the radial axis, combinations can be applied to generate a non-axisymmetric magnetic field with multiple non-uniform flux tubes. This is a considerable step forward in modeling the realistic magnetized three-dimensional equilibria of the solar atmosphere.

  4. Stellar model atmospheres with magnetic line blanketing. II. Introduction of polarized radiative transfer

    CERN Document Server

    Khan, S A

    2006-01-01

    The technique of model atmosphere calculation for magnetic Ap and Bp stars with polarized radiative transfer and magnetic line blanketing is presented. A grid of model atmospheres of A and B stars are computed. These calculations are based on direct treatment of the opacities due to the bound-bound transitions that ensures an accurate and detailed description of the line absorption and anomalous Zeeman splitting. The set of model atmospheres was calculated for the field strengths between 1 and 40 kG. The high-resolution energy distribution, photometric colors and the hydrogen Balmer line profiles are computed for magnetic stars with different metallicities and are compared to those of non-magnetic reference models and to the previous paper of this series. The results of modelling confirmed the main outcomes of the previous study: energy redistribution from UV to the visual region and flux depression at 5200A. However, we found that effects of enhanced line blanketing when transfer for polarized radiation take...

  5. A spectral line list for water isotopologues in the 1100-4100 cm-1 region for application to CO2-rich planetary atmospheres

    Science.gov (United States)

    Gamache, Robert R.; Farese, Michaella; Renaud, Candice L.

    2016-08-01

    A line list of transitions for seven isotopologues of water vapor in the 1100-4100 wavenumber range has been constructed for application to atmospheres rich in CO2. The quantum transitions for H216O, H218O, H217O, HD16O, HD18O, and HD17O are from the 2012 HITRAN database (Rothman et al., 2013) and those for D216O are from the ab initio line list of Shirin et al. (2008). The database was constructed using the best available measured parameters and augmented with theoretical calculations. The half-width, γ, its temperature dependence, n, and the line shift, δ, are for CO2 as the colliding partner or self-collisions and are determined using the Modified Complex Robert-Bonamy (MCRB) theory. The resulting line list contains 282 557 transitions and is available, in the HITRAN 2012 format, from the corresponding author or from the supplemental information of the journal.

  6. Simulating dynamics of (delta){sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

    2006-11-15

    Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of (delta){sup 13}C and thus the global (delta){sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to (delta){sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of (delta){sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The (delta){sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on (delta){sup 13}C of CO{sub 2} dynamics in PBL

  7. Simulating dynamics of {delta}{sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

    2006-11-15

    Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of {delta}{sup 13}C and thus the global {delta}{sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to {delta}{sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of {delta}{sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The {delta}{sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on {delta}{sup 13}C of CO{sub 2} dynamics in PBL

  8. Planetary Bow Shocks

    CERN Document Server

    Treumann, R A

    2008-01-01

    Our present knowledge of the properties of the various planetary bow shocks is briefly reviewed. We do not follow the astronomical ordering of the planets. We rather distinguish between magnetised and unmagnetised planets which groups Mercury and Earth with the outer giant planets of the solar system, Mars and Moon in a separate group lacking magnetic fields and dense atmospheres, and Venus together with the comets as the atmospheric celestial objects exposed to the solar wind. Asteroids would, in this classification, fall into the group together with the Moon and should behave similarly though being much smaller. Extrasolar planets are not considered as we have only remote information about their behaviour. The presentation is brief in the sense that our in situ knowledge is rather sporadic yet, depending on just a countable number of bow shock crossings from which just some basic conclusions can be drawn about size, stationarity, shape and nature of the respective shock. The only bow shock of which we have ...

  9. Formation of Zr I and II lines under non-LTE conditions of stellar atmospheres

    CERN Document Server

    Velichko, A; Nilsson, H

    2011-01-01

    The non-local thermodynaic equilibrium (non-LTE) line formation for the two ions of zirconium is considered through a range of spectral types when the Zr abundance varies from the solar value down to [Zr/H] = -3. The model atom was built using 148 energy levels of Zr I, 772 levels of Zr II, and the ground state of Zr III. It was shown that the main non-LTE mechnism for the minority species Zr I is ultraviolet overionization. Non-LTE leads to systematically depleted total absorption in the Zr I lines and positive abundance corrections, reaching to 0.33 dex for the solar metallicity models. The excited levels of Zr II are overpopulated relative to their thermodynamic equilibrium populations in the line formation layers due to radiative pumping from the low-excitation levels. As a result, the line source function exceeds the Planck function leading to weakening the Zr II lines and positive non-LTE abundance corrections. Such corrections grow towards lower metallicity and lower surface gravity and reach to 0.34 d...

  10. Fourier transform spectroscopy for future planetary missions

    Science.gov (United States)

    Brasunas, John; Kolasinski, John; Kostiuk, Ted; Hewagama, Tilak

    2017-01-01

    Thermal-emission infrared spectroscopy is a powerful tool for exploring the composition, temperature structure, and dynamics of planetary atmospheres; and the temperature of solid surfaces. A host of Fourier transform spectrometers (FTS) such as Mariner IRIS, Voyager IRIS, and Cassini CIRS from NASA Goddard have made and continue to make important new discoveries throughout the solar system. Future FTS instruments will have to be more sensitive (when we concentrate on the colder, outer reaches of the solar system), and less massive and less power-hungry as we cope with decreasing resource allotments for future planetary science instruments. With this in mind, we have developed CIRS-lite, a smaller version of the CIRS FTS for future planetary missions. We discuss the roadmap for making CIRS-lite a viable candidate for future planetary missions, including the recent increased emphasis on ocean worlds (Europa, Encelatus, Titan) and also on smaller payloads such as CubeSats and SmallSats.

  11. Small-scale heating events in the solar atmosphere. II. Lifetime, total energy, and magnetic properties

    Science.gov (United States)

    Guerreiro, N.; Haberreiter, M.; Hansteen, V.; Schmutz, W.

    2017-07-01

    Context. Small-scale heating events (SSHEs) are believed to play a fundamental role in understanding the process responsible for heating of the solar corona, the pervading redshifts in the transition region, and the acceleration of spicules. Aims: We determine the properties of the SSHEs and the atmospheric response to them in 3D magnetohydrodynamics (3D-MHD) simulations of the solar atmosphere. Methods: We developed a method for identifying and following SSHEs over their lifetime, and applied it to two simulation models. We identified the locations where the energy dissipation is greatest inside the SSHEs volume, and we traced the SSHEs by following the spatial and temporal evolution of the maximum energy dissipation inside the SSHEs volume. Results: The method is effective in following the SSHEs. We can determine their lifetime, total energy, and properties of the plasma, as well as the magnetic field orientation in the vicinity of the SSHEs. Conclusions: We determine that the SSHEs that have the potential to heat the corona live less than 4 min, and typically the energy they release ranges from 1020 to 1024 erg. In addition, the directional change of the field lines on the two sides of the current sheet constituting the SSHEs ranges from 5° to 15° at the moment of the absolute maximum energy dissipation.

  12. Activities in planetary geology for the physical and earth sciences

    Science.gov (United States)

    Dalli, R.; Greeley, R.

    1982-01-01

    A users guide for teaching activities in planetary geology, and for physical and earth sciences is presented. The following topics are discussed: cratering; aeolian processes; planetary atmospheres, in particular the Coriolis Effect and storm systems; photogeologic mapping of other planets, Moon provinces and stratigraphy, planets in stereo, land form mapping of Moon, Mercury and Mars, and geologic features of Mars.

  13. Evaluation of the efficiency and accuracy of new methods for atmospheric opacity and radiative transfer calculations in planetary general circulation model simulations

    Science.gov (United States)

    Zube, Nicholas Gerard; Zhang, Xi; Natraj, Vijay

    2016-10-01

    General circulation models often incorporate simple approximations of heating between vertically inhomogeneous layers rather than more accurate but computationally expensive radiative transfer (RT) methods. With the goal of developing a GCM package that can model both solar system bodies and exoplanets, it is vital to examine up-to-date RT models to optimize speed and accuracy for heat transfer calculations. Here, we examine a variety of interchangeable radiative transfer models in conjunction with MITGCM (Hill and Marshall, 1995). First, for atmospheric opacity calculations, we test gray approximation, line-by-line, and correlated-k methods. In combination with these, we also test RT routines using 2-stream DISORT (discrete ordinates RT), N-stream DISORT (Stamnes et al., 1988), and optimized 2-stream (Spurr and Natraj, 2011). Initial tests are run using Jupiter as an example case. The results can be compared in nine possible configurations for running a complete RT routine within a GCM. Each individual combination of opacity and RT methods is contrasted with the "ground truth" calculation provided by the line-by-line opacity and N-stream DISORT, in terms of computation speed and accuracy of the approximation methods. We also examine the effects on accuracy when performing these calculations at different time step frequencies within MITGCM. Ultimately, we will catalog and present the ideal RT routines that can replace commonly used approximations within a GCM for a significant increase in calculation accuracy, and speed comparable to the dynamical time steps of MITGCM. Future work will involve examining whether calculations in the spatial domain can also be reduced by smearing grid points into larger areas, and what effects this will have on overall accuracy.

  14. Asphalt Volcanism as a Model to Understand the Geochemical Nature of Pitch Lake, a Planetary Analog for Titan and the Implications towards Methane Flux into Earth's Atmosphere.

    Science.gov (United States)

    Khan, A.

    2016-12-01

    Pitch Lake is located in the southwest peninsula of the island near La Brea in Trinidad and Tobago, covering an area of approximately 46 hectares. It was discovered in the year 1595 and is the largest of three natural asphalt lakes that exist on Earth. Pitch Lake is a large oval shaped reservoir composed of dominantly hydrocarbon compounds, but also includes minor amounts of clay and muddy water. It is a natural liquid asphalt desert, which is nourished by a form of petroleum consisting of mostly asphaltines from the surrounding oil-rich region. The hydrocarbons mix with mud and gases under high pressure during upward seepage, and the lighter portion evaporates or is volatilized, which produces a high-viscosity liquid asphalt residue. The residue on and near the surface is a hydrocarbon matrix, which poses extremely challenging environmental conditions to microorganisms characterized by an average low water activity in the range of 0.49 to 0.75, recalcitrant carbon substrates, and toxic chemical compounds. Nevertheless, an active microbial community of archaea and bacteria, many of them novel strains, was found to inhabit the liquid hydrocarbon matrix of Pitch Lake. Geochemical analyses of minerals, done by our team, which revealed sulfates, sulfides, silicates, and metals, normally associated with deep-water hydrothermal vents leads to our new hypothetical model to describe the origins of Pitch Lake and its importance to atmospheric and earth sciences. Pitch Lake is likely the terrestrial equivalent of an offshore submarine asphalt volcano just as La Brea Tar Pits are in some ways an on-land version of the asphalt volcanoes discovered off shore of Santa Barbara by Valentine et al. in 2010. Asphalt volcanism possibly also creates the habitat for chemosynthetic life that is widespread in this lake, as reported by Schulze-Makuch et al. in 2011 and Meckenstock et al. in 2014.

  15. H2O in stellar atmospheres. II. ISO spectra of cool red giants and hydrostatic models

    Science.gov (United States)

    Aringer, B.; Kerschbaum, F.; Jörgensen, U. G.

    2002-12-01

    We present 26 ISO-SWS spectra taken from a sample of 13 M-type Semiregular, Lb and Mira variables and covering the wavelength range between 2.36 and 5 mu m at a medium resolution. All of the studied objects show intense water bands producing a deep absorption dip around 2.5 mu m. Features of CO, OH, SiO and CO2 are also visible. Using the new H2O linelist published in the first paper of this series and available opacity data for the other important molecules, we calculated a grid of hydrostatic MARCS atmospheres and the corresponding synthetic ISO-SWS spectra. Based on the comparison with these theoretical results the ISO observations can be divided into four classes. The first two groups include the spectra of the Semiregular (SRb) and Lb variables in our sample. For all of them the region between 2.36 and 4.2 mu m can be quite well reproduced by our hydrostatic models. Only the predicted SiO bands above 4 mu m are in some cases too strong which is due to known dynamical effects. Depending on the temperature (above or below 3000 K) of the atmosphere, which mainly determines the intensity of the water depression at 2.5 mu m, the spectra of the Semiregular and Lb variables fall into the first or second class. The third group consists of observations of Mira stars obtained around maximum light where the range between 2.36 and 4.2 mu m can be fitted with our MARCS models except for a strong emission bump appearing in the ISO-SWS data in the region of the SiO features and the slope very close to the short wavelength border. Finally, the last type of spectra corresponds to Mira variables during the phases around the minimum of their visual light curve. For this class the observed water absorption at 2.5 mu m is much more intense than in any hydrostatic atmosphere with a realistic choice of effective temperature and surface gravity. Thus, we conclude that dynamical models are needed to explain the ISO-SWS data of Mira stars. For all of the cooler objects from our sample

  16. STUDIES OF VARIABILITY IN PROTO-PLANETARY NEBULAE. II. LIGHT AND VELOCITY CURVE ANALYSES OF IRAS 22272+5435 AND 22223+4327

    Energy Technology Data Exchange (ETDEWEB)

    Hrivnak, Bruce J.; Lu, Wenxian [Department of Physics and Astronomy, Valparaiso University, Valparaiso, IN 46383 (United States); Sperauskas, Julius; Zacs, Laimons [Vilnius University Observatory, Ciurlionio 29 Vilnius 2009 (Lithuania); Van Winckel, Hans [Instituut voor Sterrenkunde, K. U. Leuven University, B-3001 Leuven (Heverlee) (Belgium); Bohlender, David, E-mail: bruce.hrivnak@valpo.edu, E-mail: wen.lu@valpo.edu, E-mail: julius.sperauskas@ff.vu.lt, E-mail: Hans.VanWinckel@ster.kuleuven.be, E-mail: David.Bohlender@nrc-cnrc.gc.ca, E-mail: zacs@latnet.lv [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

    2013-04-01

    We have carried out a detailed observational study of the light, color, and velocity variations of two bright, carbon-rich proto-planetary nebulae, IRAS 22223+4327 and 22272+5435. The light curves are based upon our observations from 1994 to 2011, together with published data by Arkhipova and collaborators. They each display four significant periods, with primary periods for IRAS 22223+4327 and 22272+5435 being 90 and 132 days, respectively. For each of them, the ratio of secondary to primary period is 0.95, a value much different from that found in Cepheids, but which may be characteristic of post-asymptotic giant branch (AGB) stars. Fewer significant periods are found in the smaller radial velocity data sets, but they agree with those of the light curves. The color curves generally mimic the light curves, with the objects reddest when faintest. A comparison in seasons when there exist contemporaneous light, color, and velocity curves reveals that the light and color curves are in phase, while the radial velocity curves are {approx}0.25 P out of phase with the light curves. Thus they differ from what is seen in Cepheids, in which the radial velocity curve is 0.50 P out of phase with the light curve. Comparison of the observed periods and amplitudes with those of post-AGB pulsation models shows poor agreement, especially for the periods, which are much longer than predicted. These observational data, particularly the contemporaneous light, color, and velocity curves, provide an excellent benchmark for new pulsation models of cool stars in the post-AGB, proto-planetary nebula phase.

  17. Downward surface flux computations in a vertically inhomogeneous grey planetary atmosphere Cálculo do fluxo radiativo superficial em uma atmosfera planetária cinza e verticalmente não-homogênea

    Directory of Open Access Journals (Sweden)

    Marcos Pimenta de Abreu

    2008-03-01

    Full Text Available We describe an efficient computational scheme for downward surface flux computations in a vertically inhomogeneous grey planetary atmosphere for different values of solar zenith angle. We start with the basic equations of a recently developed discrete ordinates spectral nodal method, and we derive suitable bidirectional functions whose diffuse components do not depend on the solar zenith angle. We then make use of these bidirectional functions to construct an efficient scheme for computing the downward surface fluxes in a given model atmosphere for a number of solar zenith angles. We illustrate the merit of the computational scheme described here with downward surface flux computations in a three-layer grey model atmosphere for four values of solar zenith angle, and we conclude this article with general remarks and directions for future work.Este artigo descreve um esquema computacional baseado em desenvolvimentos recentes do método espectro-nodal de ordenadas discretas para o cálculo eficiente do fluxo radiativo superficial em uma atmosfera planetária cinza e verticalmente não-homogênea para valores distintos do ângulo zenital solar. A partir das equações básicas do método espectro-nodal de ordenadas discretas, são obtidas funções bidirecionais discretas cujas componentes difusas não dependem do ângulo zenital solar. Com essas funções bidirecionais discretas, é construído um esquema computacional para calcular eficientemente fluxos radiativos superficiais em uma dada atmosfera-modelo para vários ângulos zenitais solares. O mérito computacional do esquema resultante é ilustrado com resultados numéricos para os fluxos radiativos superficiais em uma atmosfera-modelo cinza com três camadas para quatro valores distintos do ângulo zenital solar. Este artigo é finalizado com observações gerais e indicações de trabalhos futuros.

  18. Ellerman Bombs at high resolution: II. Visibility, triggering and effect on upper atmosphere

    CERN Document Server

    Vissers, Gregal J M; Rutten, Robert J

    2013-01-01

    We use high-resolution imaging spectroscopy with the Swedish 1-m Solar Telescope (SST) to study the transient brightenings of the wings of the Balmer Halpha line in emerging active regions that are called Ellerman bombs. Simultaneous sampling of Ca II 854.2 nm with the SST confirms that most Ellerman bombs occur also in the wings of this line, but with markedly different morphology. Simultaneous images from the Solar Dynamics Observatory (SDO) show that Ellerman bombs are also detectable in the photospheric 170 nm continuum, again with differing morphology. They are also observable in 160 nm SDO images, but with much contamination from C IV emission in transition-region features. Simultaneous SST spectropolarimetry in Fe I 630.1 nm shows that Ellerman bombs occur at sites of strong-field magnetic flux cancelation between small bipolar strong-field patches that rapidly move together over the solar surface. Simultaneous SDO images in He II 30.4 nm, Fe IX 17.1 nm, and Fe XIV 21.1 nm show no clear effect of the E...

  19. Indo-Pacific variability on seasonal to multidecadal timescales. Part II: Multiscale atmosphere-ocean linkages

    CERN Document Server

    Giannakis, Dimitrios

    2016-01-01

    The coupled atmosphere-ocean variability of the Indo-Pacific on interannual to multidecadal timescales is investigated in a millennial control run of CCSM4 and in observations using a family of modes recovered in Part~I of this work from unprocessed SST data through nonlinear Laplacian spectral analysis (NLSA). It is found that ENSO and combination modes of ENSO with the annual cycle exhibit a seasonally synchronized southward shift of equatorial surface zonal winds and thermocline adjustment consistent with terminating El Nino and La Nina events. The surface wind patterns associated with these modes also generate teleconnections between the Pacific and Indian Oceans, leading to a pattern of SST anomalies characteristic of the Indian Ocean dipole. Fundamental and combination modes representing the tropospheric biennial oscillation (TBO) in CCSM4 are also found to be consistent with mechanisms for seasonally synchronized biennial variability of the Asian-Australian monsoon and Walker circulation. On longer tim...

  20. Analytical Models of Exoplanetary Atmospheres. II. Radiative Transfer via the Two-Stream Approximation

    CERN Document Server

    Heng, Kevin; Lee, Jaemin

    2014-01-01

    We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and solutions describing two-stream radiative transfer (which approximates the passage of radiation as a pair of outgoing and incoming fluxes), flux-limited diffusion (which describes radiative transfer in the deep interior) and solutions for the temperature-pressure profiles. Generally, the problem is mathematically under-determined unless a set of closures (Eddington coefficients) is specified. We demonstrate that the hemispheric (or hemi-isotropic) closure naturally derives from the radiative transfer equation if energy conservation is obeyed, while the Eddington closure produces spurious enhancements of both reflected light and thermal emission. We further demonstrate that traditional non-isothermal treatments of each atmospheric layer lead to unphysical contributions to the ...

  1. The optical reflector system for the CANGAROO-II imaging atmospheric Cherenkov telescope

    Science.gov (United States)

    Kawachi, A.; Hayami, Y.; Jimbo, J.; Kamei, S.; Kifune, T.; Kubo, H.; Kushida, J.; LeBohec, S.; Miyawaki, K.; Mori, M.; Nishijima, K.; Patterson, J. R.; Suzuki, R.; Tanimori, T.; Yanagita, S.; Yoshikoshi, T.; Yuki, A.

    2001-01-01

    A new imaging atmospheric Cherenkov telescope with a light-weight reflector has been constructed. Light, robust, and durable mirror facets of containing carbon fiber reinforced plastic laminates were developed for the telescope. The reflector has a parabolic shape ( f/1.1) with a 30 m 2 surface area, which consists of 60 spherical mirror facets. The image size of each mirror facet is 0°.08 (FWHM) on average. The attitude of each facet can be adjusted by stepping motors. After the first in situ adjustment, a point image of about 0°.14 (FWHM) over 3° field of view was obtained. The effect of gravitational load on the optical system was confirmed to be negligible at the focal plane. The telescope has been in operation with an energy threshold for γ-rays of ≲300 GeV since May 1999.

  2. Isothermal magnetostatic atmospheres. II - Similarity solutions with current proportional to the magnetic potential cubed

    Science.gov (United States)

    Webb, G. M.

    1988-01-01

    The paper presents a family of isothermal magnetostatic atmospheres with one ignorable coordinate corresponding to a uniform gravitational field in a plane geometry. The distributed current in the model J is directed along the x-axis, where x is the horizontal ignorable coordinate. The current J is taken to be proportional to the cube of the magnetostatic potential A and falls off exponentially with distance vertical to the base with an e-folding distance equal to the gravitational scale height. A range of similarity solution examples are displayed depending on the values of the similarity parameters. Each similarity parameter corresponds to a symmetry of the underlying nonlinear elliptic equation for A. The similarity parameters also determine the source currents for the potential field solution of the family. The solutions show the interplay between the gravitational force, the J & B force (B, magnetic field induction) and the gas pressure gradient.

  3. Magnetohydrostatic equilibrium. II. Three-dimensional multiple open magnetic flux tubes in the stratified solar atmosphere

    CERN Document Server

    Gent, Frederick A; Erd'elyi, Rebertus

    2014-01-01

    A system of multiple open magnetic flux tubes spanning the solar photosphere and lower corona is modelled analytically, within a realistic stratified atmosphere subject to solar gravity. This extends results for a single magnetic flux tube in magnetohydrostatic equilibrium, described in Gent et al. (MNRAS, 435, 689, 2013). Self-similar magnetic flux tubes are combined to form magnetic structures, which are consistent with high-resolution observations. The observational evidence supports the existence of strands of open flux tubes and loops persisting in a relatively steady state. Self-similar magnetic flux tubes, for which an analytic solution to the plasma density and pressure distribution is possible, are combined. We calculate the appropriate balancing forces, applying to the equations of momentum and energy conservation to preserve equilibrium. Multiplex flux tube configurations are observed to remain relatively stable for up to a day or more, and it is our aim to apply our model as the background conditi...

  4. Atmospheric neutrino oscillation analysis with sub-leading effects in Super-Kamiokande I, II, and III

    CERN Document Server

    Wendell, R; Abe, K; Hayato, Y; Iida, T; Ikeda, M; Iyogi, K; Kameda, J; Kobayashi, K; Koshio, Y; Kozuma, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Ogawa, H; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Yokozawa, T; Hazama, S; Kaji, H; Kajita, T; Kaneyuki, K; McLachlan, T; Okumura, K; Shimizu, Y; Tanimoto, N; Vagins, M R; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Wang, W; Goldhaber, M; Bays, K; Casper, D; Cravens, J P; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J; Fechner, M; Scholberg, K; Walter, C W; Tasaka, S; Learned, J G; Matsuno, S; Watanabe, Y; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Nishino, H; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Fukuda, Y; Itow, Y; Mitsuka, G; Tanaka, T; Jung, C K; Lopez, G; McGrew, C; Yanagisawa, C; Tamura, N; Ishino, H; Kibayashi, A; Mino, S; Mori, T; Sakuda, M; Toyota, H; Kuno, Y; Yoshida, M; Kim, S B; Yang, B S; Ishizuka, T; Okazawa, H; Choi, Y; Nishijima, K; Yokosawa, Y; Koshiba, M; Yokoyama, M; Totsuka, Y; Chen, S; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Mijakowski, P; Connolly, K; Dziomba, M; Thrane, E; Wilkes, R J

    2010-01-01

    We present a search for non-zero theta_{13} and deviations of sin^2 theta_{23} from 0.5 in the oscillations of atmospheric neutrino data of Super-Kamiokande -I, -II, and -III. No distortions of the neutrino flux consistent with non-zero theta_{13} are found and both neutrino mass hierarchy hypotheses are in agreement with the data. The data are best fit at Delta m^2 = 2.1 x 10^-3 eV^2, sin^2 theta_{13} = 0.0, and sin^2 theta_{23} =0.5. In the normal (inverted) hierarchy theta_{13} and Delta m^2 are constrained at the one-dimensional 90% C.L. to sin^2 theta_{13} < 0.04 (0.09) and 1.9 (1.7) x 10^-3 < Delta m^2 < 2.6 (2.7) x 10^-3 eV^2. The atmospheric mixing angle is within 0.407 <= sin^2 theta_{23} <= 0.583 at 90% C.L.

  5. The effect of carbon monoxide on planetary haze formation

    Energy Technology Data Exchange (ETDEWEB)

    Hörst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2014-01-20

    Organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface. Numerous experiments have investigated the aerosols produced by exposing mixtures of N{sub 2}/CH{sub 4} to a variety of energy sources. However, many N{sub 2}/CH{sub 4} atmospheres in both our solar system and extrasolar planetary systems also contain carbon monoxide (CO). We have conducted a series of atmosphere simulation experiments to investigate the effect of CO on the formation and particle size of planetary haze analogues for a range of CO mixing ratios using two different energy sources, spark discharge and UV. We find that CO strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that CO may play an important, previously unexplored, role in aerosol chemistry in planetary atmospheres.

  6. Low-Power Wideband Digital Spectrometer for Planetary Science Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to develop a wideband digital spectrometer to support space-born measurements of planetary atmospheric composition. The spectrometer...

  7. The Effect of CO on Planetary Haze Formation

    CERN Document Server

    Hörst, Sarah M

    2014-01-01

    Organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface. Numerous experiments have investigated the aerosols produced by exposing mixtures of N$_{2}$/CH$_{4}$ to a variety of energy sources. However, many N$_{2}$/CH$_{4}$ atmospheres in both our solar system and extrasolar planetary systems also contain CO. We have conducted a series of atmosphere simulation experiments to investigate the effect of CO on formation and particle size of planetary haze analogues for a range of CO mixing ratios using two different energy sources, spark discharge and UV. We find that CO strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that CO may play an important, previously unexplored, role in aerosol chemistry in planetary atmospheres.

  8. Planetary Boundaries: Exploring the Safe Operating Space for Humanity

    Directory of Open Access Journals (Sweden)

    Johan Rockström

    2009-12-01

    Full Text Available Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere

  9. A selection of hot subluminous stars in the GALEX survey II. Subdwarf atmospheric parameters

    CERN Document Server

    Németh, Péter; Vennes, Stéphane

    2012-01-01

    We present an update of our low-resolution spectroscopic follow-up and model atmosphere analysis of hot subdwarf stars from the Galaxy Evolution Explorer (GALEX) survey. Targets were selected on the basis of colour indices calculated from the GALEX GR6 N_UV, Guide Star Catalogue (GSC2.3.2) V and the Two Micron All Sky Survey (2MASS) J and H photometry. High signal-to-noise ratio spectra were obtained at the European Southern Observatory (ESO) and the Kitt Peak National Observatory (KPNO) over the course of three years. Detailed H, He and CNO abundance analysis helped us improve our T_eff, log g and He abundance determination and to constrain CNO abundances. We processed 191 observations of 180 targets and found 124 sdB and 42 sdO stars in this sample while some blue horizontal branch stars were also found in this programme. With quantitative binary decomposition of 29 composite spectra we investigated the incidence of A, F and G type companions. The incidence of late G and K type companions and their effects ...

  10. The Role of Type II Spicules in the Upper Solar Atmosphere

    CERN Document Server

    Klimchuk, J A

    2012-01-01

    We examine the suggestion that most of the hot plasma in the Sun's corona comes from type II spicule material that is heated as it is ejected from the chromosphere. This contrasts with the traditional view that the corona is filled via chromospheric evaporation that results from coronal heating. We explore the observational consequences of a hypothetical spicule dominated corona and conclude from the large discrepancy between predicted and actual observations that only a small fraction of the hot plasma can be supplied by spicules (<2% in active regions and <5% in the quiet Sun). The red-blue asymmetries of EUV spectral lines and the ratio of lower transition region (LTR; T<0.1 MK) to coronal emission measures are both predicted to be 2 orders of magnitude larger than observed. Furthermore, hot spicule material would cool dramatically by adiabatic expansion as it rises into the corona, so coronal heating would be required to maintain the high temperatures that are seen at all altitudes. The necessity...

  11. Planetary satellites - an update

    Science.gov (United States)

    Beatty, J. K.

    1983-11-01

    General features of all known planetary satellites in the system are provided, and attention is focused on prominent features of several of the bodies. Titan has an atmosphere 1.5 times earth's at sea level, a well a a large body of liquid which may be ethane, CH4, and disolved N2. Uranus has at least five moons, whose masses have recently been recalculated and determined to be consistent with predictions of outer solar system composition. Io's violent volcanic activity is a demonstration of the conversion of total energy (from Jupiter) to heat, i.e., interior melting and consequent volcanoes. Plumes of SO2 have been seen and feature temperatures of up to 650 K. Enceladus has a craterless, cracked surface, indicating the presence of interior ice and occasional breakthroughs from tidal heating. Hyperion has a chaotic rotation, and Iapetus has one light and one dark side, possibly from periodic collisions with debris clouds blasted off the surface of the outer moon Phoebe.

  12. The DODO Survey II: A Gemini Direct Imaging Search for Substellar and Planetary Mass Companions around Nearby Equatorial and Northern Hemisphere White Dwarfs

    CERN Document Server

    Hogan, E; Clarke, F J

    2009-01-01

    The aim of the Degenerate Objects around Degenerate Objects (DODO) survey is to search for very low mass brown dwarfs and extrasolar planets in wide orbits around white dwarfs via direct imaging. The direct detection of such companions would allow the spectroscopic investigation of objects with temperatures much lower ( T8.5 and so could belong to the proposed Y dwarf spectral sequence. The detection of a planet around a white dwarf would prove that such objects can survive the final stages of stellar evolution and place constraints on the frequency of planetary systems around their progenitors (with masses between 1.5 - 8 solar masses, i.e., early B to mid F). This paper presents the results of a multi-epoch J band common proper motion survey of 23 nearby equatorial and northern hemisphere white dwarfs. We rule out the presence of any common proper motion companions, with limiting masses determined from the completeness limit of each observation, to 18 white dwarfs. For the remaining five targets, the motion...

  13. The DODO survey - II. A Gemini direct imaging search for substellar and planetary mass companions around nearby equatorial and Northern hemisphere white dwarfs

    Science.gov (United States)

    Hogan, E.; Burleigh, M. R.; Clarke, F. J.

    2009-07-01

    The aim of the Degenerate Objects around Degenerate Objects (DODO) survey is to search for very low-mass brown dwarfs and extrasolar planets in wide orbits around white dwarfs via direct imaging. The direct detection of such companions would allow the spectroscopic investigation of objects with temperatures much lower (T8.5, and so could belong to the proposed Y dwarf spectral sequence. The detection of a planet around a white dwarf would prove that such objects can survive the final stages of stellar evolution and place constraints on the frequency of planetary systems around their progenitors (with masses between 1.5 and 8Msolar, i.e. early B to mid-F). This paper presents the results of a multi epoch J band common proper motion survey of 23 nearby equatorial and Northern hemisphere white dwarfs. We rule out the presence of any common proper motion companions, with limiting masses determined from the completeness limit of each observation, to 18 white dwarfs. For the remaining five targets, the motion of the white dwarf is not sufficiently separated from the non-moving background objects in each field. These targets require additional observations to conclusively rule out the presence of any common proper motion companions. From our completeness limits, we tentatively suggest that ~ 500 K between projected physical separations of 60-200 au.

  14. A deep survey of heavy element lines in planetary nebulae -- II. Recombination line abundances and evidence for ultra-cold plasma

    CERN Document Server

    Tsamis, Y G; Liu, X W; Storey, P J; Danziger, I J

    2004-01-01

    [Abridged] Deep optical observations of the spectra of 12 Galactic planetary nebulae (PNe) and 3 Magellanic Cloud PNe were presented in Paper I by Tsamis et al. (2003b), who carried out an abundance analysis using the collisionally excited forbidden lines. Here, the relative intensities of faint optical recombination lines (ORLs) from ions of carbon, nitrogen and oxygen are analysed in order to derive the abundances of these ions relative to hydrogen. We define an abundance discrepancy factor (ADF) as the ratio of the abundance derived for a heavy element ion from its recombination lines to that derived for the same ion from its ultraviolet, optical or infrared collisionally excited lines (CELs). All of the PNe in our sample are found to have ADF's that exceed unity. There is no dependence of the magnitude of the ADF upon the excitation energy of the UV, optical or IR CEL transition used, indicating that classical nebular temperature fluctuations--i.e. in a chemically homogeneous medium--are not the cause of ...

  15. A Model for the Spectral Albedo of Snow. II: Snow Containing Atmospheric Aerosols.

    Science.gov (United States)

    Warren, Stephen G.; Wiscombe, Warren J.

    1980-12-01

    visible is a systematic effect and always results in more energy being absorbed at a snow-covered surface than would be the case for pure snow. Thus man-made carbon soot aerosol may continue to exert a significant warming effect on the earth's climate even after it is removed from the atmosphere.

  16. NKS NordRisk II: Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    DEFF Research Database (Denmark)

    Smith Korsholm, Ulrik; Astrup, Poul; Lauritzen, Bent;

    The present atlas has been developed within the NKS/NordRisk-II project "Nuclear risk from atmospheric dispersion in Northern Europe". The atlas describes risks from hypothetical long-range dispersion and deposition of radionuclides from 16 nuclear risk sites on the Northern Hemisphere...

  17. From Planetary Intelligence to Planetary Wisdom

    Science.gov (United States)

    Moser, S. C.

    2016-12-01

    "Planetary intelligence" - when understood as an input into the processes of "managing" Earth - hints at an instrumental understanding of scientific information. At minimum it is a call for useful data of political (and even military) value; at best it speaks to an ability to collect, integrate and apply such information. In this sense, 21st century society has more "intelligence" than any generation of humans before, begging the question whether just more or better "planetary intelligence" will do anything at all to move us off the path of planetary destruction (i.e., beyond planetary boundaries) that it has been on for decades if not centuries. Social scientists have argued that there are at least four shortcomings in this way of thinking that - if addressed - could open up 1) what is being researched; 2) what is considered socially robust knowledge; 3) how science interacts with policy-makers and other "planet managers"; and 4) what is being done in practice with the "intelligence" given to those positioned at the levers of change. To the extent "planetary management" continues to be approached from a scientistic paradigm alone, there is little hope that Earth's future will remain in a safe operating space in this or coming centuries.

  18. Assimilation of atmospheric methane products in the MACC-II system: from SCIAMACHY to TANSO and IASI

    Directory of Open Access Journals (Sweden)

    S. Massart

    2014-01-01

    Full Text Available The Monitoring Atmospheric Composition and Climate Interim Implementation (MACC-II delayed-mode (DM system has been producing an atmospheric methane (CH4 analysis 6 months behind real time since June 2009. This analysis used to rely on the assimilation of the CH4 product from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY instrument on board Envisat. Recently the \\textit{Laboratoire de Météorologie Dynamique} (LMD CH4 products from the Infrared Atmospheric Sounding Interferometer (IASI and the SRON Netherlands Institute for Space Research CH4 products from the Thermal And Near-infrared Sensor for carbon Observation (TANSO were added to the DM system. With the loss of Envisat in April 2012, the DM system has to now rely on the assimilation of methane data from TANSO and IASI. This paper documents the impact of this change in the observing system on the methane tropospheric analysis. It is based on four experiments: one free run and three analyses from respectively the assimilation of SCIAMACHY, TANSO and a combination of TANSO and IASI CH4 products in the MACC-II system. The period between December 2010 and April 2012 is studied. This corresponds to a period during which the performance of SCIAMACHY was deteriorating. The SCIAMACHY experiment globally underestimates the tropospheric methane by 35 part per billion (ppb compared to the HIAPER Pole-to-Pole Observations (HIPPO data and the methane column by 23 ppb compared the Total Carbon Column Observing Network (TCCON data, when the global bias of the free run against the same HIPPO and TCCON data is respectively −5 ppb and 4 ppb. The assimilated TANSO product changed in October 2011 from version v.1 to version v.2.0. The analysis of version v.1 globally underestimates the tropospheric methane by 18 ppb compared to the HIPPO data and the column by 11 ppb compared to the TCCON data. In contrast, the analysis of version v.2.0 globally overestimates the

  19. UV spectroscopy of Titan's atmosphere, planetary organic chemistry and prebiological synthesis. II - Interpretation of new IUE observations in the 220-335 nm range

    Science.gov (United States)

    Courtin, Regis; Wagener, Richard; Mckay, Christopher P.; Caldwell, John; Fricke, Karl-Heinrich

    1991-01-01

    The theoretical model developed by McKay et al. (1989) to characterize the size distribution, thermal structure, and chemical composition of the stratospheric haze of Titan is applied to new 220-335-nm albedo measurements obtained with the long-wavelength prime camera of the IUE during August 1987. Data and model predictions are presented in extensive graphs and discussed in detail. It is shown that a simple model with particles of one size at a given altitude does not accurately reproduce the observed features in all spectral regions, but that good general agreement is obtained using a model with a uniformly mixed layer at 150-600 km and a bimodal distribution of small 'polymer' haze particles (radius less than 20 nm) and larger haze particles (radius 100-500 nm). The number densities implied by this model require, however, a mechanism such as electrostatic charging or reaction kinetics to inhibit coagulation of the smaller particles.

  20. UV spectroscopy of Titan's atmosphere, planetary organic chemistry and prebiological synthesis. II. Interpretation of new IUE observations in the 220-335 nm range.

    Science.gov (United States)

    Courtin, R; Wagener, R; McKay, C P; Caldwell, J; Fricke K-H; Raulin, F; Bruston, P

    1991-01-01

    We report on new observations of Titan with the International Ultraviolet Explorer in the mid-UV range (lambda approximately 220-335 nm). We use these data to determine upper limits for the abundances of simple organic compounds in the gas phase and to further constrain the properties of the high altitude haze on Titan. As a baseline, we adopted the parametrized microphysical model of McKay et al. (1989) which is successful at reproducing Titan's thermal structure while satisfying several other observational constraints in the visible and IR regions. However, we find that such a model--in which all particles at a given altitude are assumed to have the same size--cannot match simultaneously the IUE observations and the visible/IR data, even when allowance is made for a wide range of values in the adjustable parameters. On the other hand, a good overall agreement is obtained when considering a biomodal size distribution, with small haze particles or "polymers" (r UV, visible, and IR regions. This approach is consistent with the results of several previous investigations of the properties of Titan's haze, although our preferred vertical structure for the haze + polymer material somewhat differs from earlier solutions. On the basis of simple dynamical considerations, we adopted a uniformly mixed layer between 150 and 600 km. The IUE data allow us to place fairly stringent constraints on the abundance of the Rayleigh absorbers, if we assume that their optical properties are similar to those of laboratory-synthesized "tholins": The column-mass density of this material--the essential observable that can be determined from our study--is of the order of 5 micrograms cm-2. This would correspond to number-densities between 10(3) and 10(7) cm-3 in the 150-600 km altitude range, if the average particle radius is between 0.001 and 0.02 micrometer. Such high number densities are a priori at odds with the estimated coagulation lifetime for particles of that size. Thus, our proposed bimodal size distribution is plausible only if inhibiting processes act to slow down considerably the coagulation of polymers in Titan's stratosphere.

  1. Liberating exomoons in white dwarf planetary systems

    CERN Document Server

    Payne, Matthew J; Holman, Matthew J; Gaensicke, Boris T

    2016-01-01

    Previous studies indicate that more than a quarter of all white dwarf (WD) atmospheres are polluted by remnant planetary material, with some WDs being observed to accrete the mass of Pluto in 10^6 years. The short sinking timescale for the pollutants indicate that the material must be frequently replenished. Moons may contribute decisively to this pollution process if they are liberated from their parent planets during the post-main-sequence evolution of the planetary systems. Here, we demonstrate that gravitational scattering events among planets in WD systems easily triggers moon ejection. Repeated close encounters within tenths of a planetary Hill radii are highly destructive to even the most massive, close-in moons. Consequently, scattering increases both the frequency of perturbing agents in WD systems, as well as the available mass of polluting material in those systems, thereby enhancing opportunities for collision and fragmentation and providing more dynamical pathways for smaller bodies to reach the ...

  2. Planetary data definition

    Science.gov (United States)

    1984-10-01

    Planetary data include all of those data which have resulted from measurements made by the instruments carried aboard planetary exploration spacecraft, and (for our purposes) exclude observations of Moon and Earth. The working, planetary data base is envisioned to contain not only these data, but also a wide range of supporting measurements such as calibration files, navigation parameters, spacecraft engineering states, and the various Earth-based and laboratory measurements which provide the planetary research scientist with historical and comparative data. No convention exists across the disciplines of the planetary community for defining or naming the various levels through which data pass in the progression from a sensed impulse at the spacecraft to a reduced, calibrated, and/or analyzed element in a planetary data set. Terms such as EDR (experiment data record), RDR (reduced data record), and SEDR (supplementary experiment data record) imply different meanings depending on the data set under consideration. The development of standard terminology for the general levels of planetary data is necessary.

  3. Planetary Simulation Chambers bring Mars to laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Mateo-Marti, E.

    2016-07-01

    Although space missions provide fundamental and unique knowledge for planetary exploration, they are always costly and extremely time-consuming. Due to the obvious technical and economical limitations of in-situ planetary exploration, laboratory simulations are among the most feasible research options for making advances in planetary exploration. Therefore, laboratory simulations of planetary environments are a necessary and complementary option to expensive space missions. Simulation chambers are economical, more versatile, and allow for a higher number of experiments than space missions. Laboratory-based facilities are able to mimic the conditions found in the atmospheres and on the surfaces of a majority of planetary objects. Number of relevant applications in Mars planetary exploration will be described in order to provide an understanding about the potential and flexibility of planetary simulation chambers systems: mainly, stability and presence of certain minerals on Mars surface; and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will be a promising tools and necessary platform to design future planetary space mission and to validate in-situ measurements from orbital or rover observations. (Author)

  4. the Martian atmospheric boundary layer

    DEFF Research Database (Denmark)

    Petrosyan, A.; Galperin, B.; Larsen, Søren Ejling

    2011-01-01

    The planetary boundary layer (PBL) represents the part of the atmosphere that is strongly influenced by the presence of the underlying surface and mediates the key interactions between the atmosphere and the surface. On Mars, this represents the lowest 10 km of the atmosphere during the daytime...

  5. Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-Mass Dwarf Stars II. Sulfur and Phosphorus

    CERN Document Server

    Visscher, C

    2005-01-01

    We use thermochemical equilibrium and kinetic calculations to model sulfur and phosphorus chemistry in the atmospheres of giant planets, brown dwarfs, low-mass stars, and extrasolar giant planets (EGPs). The chemical behavior of individual S- and P-bearing gases and condensates is determined as a function of pressure, temperature, and metallicity. Our results are independent of any particular model atmosphere and the behavior of different gases can be used to constrain atmospheric structure and metallicity. Hydrogen sulfide is the dominant sulfur gas in substellar atmospheres and approximately represents the atmospheric sulfur inventory. Depending on the prevailing S and C chemistry, the abundance of minor sulfur gases may constrain atmospheric temperatures or metallicity. Disequilibrium abundances of PH3 are expected in the observable atmospheres of substellar objects, and PH3 is representative of the total P abundance in giant planets and T dwarfs. A number of other phosphorus gases become relatively abunda...

  6. Planetary mass function and planetary systems

    CERN Document Server

    Dominik, M

    2010-01-01

    With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the properties of their respective host stars. This can be accounted for by describing planet populations by means of a differential planetary mass-radius-orbit function, which together with the fraction of stars with given properties that are orbited by planets and the stellar mass function allows to derive all statistics for any considered sample. These fundamental functions provide a framework for comparing statistics that result from different observing techniques and campaigns which all have their very specific selection procedures and detection efficiencies. Moreover, recent results both from gravitational microlensing campaigns and radial-velocity surveys of stars indicate that planets tend to cluster in systems rather than being the lonely child of their r...

  7. The Planetary Project

    Science.gov (United States)

    Pataki, Louis P.

    2016-06-01

    This poster presentation presents the Planetary Project, a multi-week simulated research experience for college non-science majors. Students work in research teams of three to investigate the properties of a fictitious planetary system (the “Planetary System”) created each semester by the instructor. The students write team and individual papers in which they use the available data to draw conclusions about planets, other objects or general properties of the Planetary System and in which they compare, contrast and explain the similarities between the objects in the Planetary System and comparable objects in the Solar System.Data about the orbital and physical properties of the planets in the Planetary System are released at the start of the project. Each week the teams request data from a changing pool of available data. For example, in week one pictures of the planets are available. Each team picks one planet and the data (pictures) on that planet are released only to that team. Different data are available in subsequent weeks. Occasionally a news release to all groups reports an unusual occurrence - e.g. the appearance of a comet.Each student acts as principal author for one of the group paper which must contain a description of the week’s data, conclusions derived from that data about the Planetary System and a comparison with the Solar System. Each students writes a final, individual paper on a topic of their choice dealing with the Planetary System in which they follow the same data, conclusion, comparison format. Students “publish” their papers on a class-only restricted website and present their discoveries in class talks. Data are released to all on the website as the related papers are “published.” Additional papers commenting on the published work and released data are encouraged.The successes and problems of the method are presented.

  8. NKS NordRisk II: Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    Energy Technology Data Exchange (ETDEWEB)

    Smith Korsholm, U.; Havskov Soerensen, J. (Danish Meteorological Institute (DMI), Copenhagen (Denmark)); Astrup, P.; Lauritzen, B. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Radiation Research Div., Roskilde (Denmark))

    2011-04-15

    The present atlas has been developed within the NKS/NordRisk-II project 'Nuclear risk from atmospheric dispersion in Northern Europe'. The atlas describes risks from hypothetical long-range dispersion and deposition of radionuclides from 16 nuclear risk sites on the Northern Hemisphere. The atmospheric dispersion model calculations cover a period of 30 days following each release to ensure almost complete deposition of the dispersed material. The atlas contains maps showing the total deposition and time-integrated air concentration of Cs-137 and I-131 based on three years of meteorological data spanning the climate variability associated with the North Atlantic Oscillation, and corresponding time evolution of the ensemble mean atmospheric dispersion. (Author)

  9. Europa Planetary Protection for Juno Jupiter Orbiter

    Science.gov (United States)

    Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

    2010-01-01

    NASA's Juno mission launched in 2011 and will explore the Jupiter system starting in 2016. Juno's suite of instruments is designed to investigate the atmosphere, gravitational fields, magnetic fields, and auroral regions. Its low perijove polar orbit will allow it to explore portions of the Jovian environment never before visited. While the Juno mission is not orbiting or flying close to Europa or the other Galilean satellites, planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design.The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

  10. Zn(II, Mn(II and Sr(II Behavior in a Natural Carbonate Reservoir System. Part I: Impact of Salinity, Initial pH and Initial Zn(II Concentration in Atmospheric Conditions

    Directory of Open Access Journals (Sweden)

    Auffray B.

    2016-07-01

    Full Text Available The sorption of inorganic elements on carbonate minerals is well known in strictly controlled conditions which limit the impact of other phenomena such as dissolution and/or precipitation. In this study, we evidence the behavior of Zn(II (initially in solution and two trace elements, Mn(II and Sr(II (released by carbonate dissolution in the context of a leakage from a CO2 storage site. The initial pH chosen are either equal to the pH of the water-CO2 equilibrium (~ 2.98 or equal to the pH of the water-CO2-calcite system (~ 4.8 in CO2 storage conditions. From this initial influx of liquid, saturated or not with respect to calcite, the batch experiments evolve freely to their equilibrium, as it would occur in a natural context after a perturbation. The batch experiments are carried out on two natural carbonates (from Lavoux and St-Emilion with PCO2 = 10−3.5 bar, with different initial conditions ([Zn(II]i from 10−4 to 10−6 M, either with pure water or 100 g/L NaCl brine. The equilibrium regarding calcite dissolution is confirmed in all experiments, while the zinc sorption evidenced does not always correspond to the two-step mechanism described in the literature. A preferential sorption of about 10% of the concentration is evidenced for Mn(II in aqueous experiments, while Sr(II is more sorbed in saline conditions. This study also shows that this preferential sorption, depending on the salinity, is independent of the natural carbonate considered. Then, the simulations carried out with PHREEQC show that experiments and simulations match well concerning the equilibrium of dissolution and the sole zinc sorption, with log KZn(II ~ 2 in pure water and close to 4 in high salinity conditions. When the simulations were possible, the log K values for Mn(II and Sr(II were much different from those in the literature obtained by sorption in controlled conditions. It is shown that a new conceptual model regarding multiple Trace Elements (TE sorption is

  11. Planetary cartography in the next decade (1984 - 1994)

    Science.gov (United States)

    1984-01-01

    The cartographic products required to support science and planetary exploration during the next 10 years were assessed. Only major map series or first order maps needed to characterize the surface physiography of a planet or satellite were considered. Included in these considerations are maps needed as bases for plotting geologic, geophysical, and atmospheric phenomena and for planning future planetary exploration. These products consist of three types of maps: controlled photomosaics, shaded relief maps, and topographic contour maps.

  12. Planetary/DOD entry technology flight experiments. Volume 2: Planetary entry flight experiments

    Science.gov (United States)

    Christensen, H. E.; Krieger, R. J.; Mcneilly, W. R.; Vetter, H. C.

    1976-01-01

    The technical feasibility of launching a high speed, earth entry vehicle from the space shuttle to advance technology for the exploration of the outer planets' atmospheres was established. Disciplines of thermodynamics, orbital mechanics, aerodynamics propulsion, structures, design, electronics and system integration focused on the goal of producing outer planet environments on a probe shaped vehicle during an earth entry. Major aspects of analysis and vehicle design studied include: planetary environments, earth entry environment capability, mission maneuvers, capabilities of shuttle upper stages, a comparison of earth entry planetary environments, experiment design and vehicle design.

  13. Data catalog series for space science and applications flight missions. Volume 1A: Brief descriptions of planetary and heliocentric spacecraft and investigations

    Science.gov (United States)

    Cameron, W. S. (Editor); Vostreys, R. W. (Editor)

    1982-01-01

    Planetary and heliocentric spacecraft, including planetary flybys and probes, are described. Imaging, particles and fields, ultraviolet, infrared, radio science and celestial mechanics, atmospheres, surface chemistry, biology, and polarization are discussed.

  14. Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    André, N.; Grande, M.

    2015-10-01

    Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI) will include an entirely new Virtual Access Service, WP5 VA1 "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. VA1 will make five entirely new 'toolkits' accessible to the research community and to industrial partners planning for space missions: a general planetary space weather toolkit, as well as three toolkits dedicated to the following key planetary environments: Mars (in support ExoMars), comets (building on the expected success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUICE mission to be launched in 2022). This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather in the tools and models available within the partner institutes. It will also create a novel event-diary toolkit aiming at predicting and detecting planetary events like meteor showers and impacts. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. So WP10 JRA4 "Planetary Space Weather Services" (PSWS) will provide the additional research and tailoring required to apply them for these purposes. The overall objectives of this JRA will be to review, test, improve and adapt methods and tools available within the partner institutes in order to make prototype planetary event and space weather services operational in Europe at the end of

  15. The final fate of planetary systems

    Science.gov (United States)

    Gaensicke, Boris

    2015-12-01

    The discovery of the first extra-solar planet around a main-sequence star in 1995 has changed the way we think about the Universe: our solar system is not unique. Twenty years later, we know that planetary systems are ubiquitous, orbit stars spanning a wide range in mass, and form in an astonishing variety of architectures. Yet, one fascinating aspect of planetary systems has received relatively little attention so far: their ultimate fate.Most planet hosts will eventually evolve into white dwarfs, Earth-sized stellar embers, and the outer parts of their planetary systems (in the solar system, Mars and beyond) can survive largely intact for billions of years. While scattered and tidally disrupted planetesimals are directly detected at a small number of white dwarfs in the form infrared excess, the most powerful probe for detecting evolved planetary systems is metal pollution of the otherwise pristine H/He atmospheres.I will present the results of a multi-cycle HST survey that has obtained COS observations of 136 white dwarfs. These ultraviolet spectra are exquisitely sensitive to the presence of metals contaminating the white atmosphere. Our sophisticated model atmosphere analysis demonstrates that at least 27% of all targets are currently accreting planetary debris, and an additional 29% have very likely done so in the past. These numbers suggest that planet formation around A-stars (the dominant progenitors of today's white dwarf population) is similarly efficient as around FGK stars.In addition to post-main sequence planetary system demographics, spectroscopy of the debris-polluted white dwarf atmospheres provides a direct window into the bulk composition of exo-planetesimals, analogous to the way we use of meteorites to determine solar-system abundances. Our ultraviolet spectroscopy is particularly sensitive to the detection of Si, a dominant rock-forming species, and we identify up to ten additional volatile and refractory elements in the most strongly

  16. Quasi-Stationary Planetary Wave in the MLT During Summer

    Science.gov (United States)

    Stray, N. H.; Espy, P. J.; Hibbins, R. E.

    2014-12-01

    A network of 8 northern hemispheric SuperDARN radars (51-66N) has been used to study planetary wave activity in the mesosphere lower thermosphere (MLT). The meridional meteor winds from the longitudinally spaced SuperDARN network are used to derive the planetary wave activity with zonal wave numbers 1 and 2 in the polar summer MLT (~95 km). In addition planetary wave amplitudes throughout the middle atmosphere have been retrieved from the meridional wind data of the Modern-Era Retrospective Analysis for Research and Application (MERRA) of the NASA Global Modelling and Assimilation Office. The fitting technique used to derive the planetary wave amplitudes will be presented, and it will be shown that there are strong quasi-stationary longitudinal differences in the strength of the meridional wind in the MLT during summer which can be described as a quasi-stationary planetary wave number 1. The ground-based network allows this planetary wave to be separated from tidal perturbations that are aliased in satellite observations, and the combination of these two data sets provides evidence that the mesopause planetary wave activity is produced in situ in the MLT rather than propagating upwards from lower altitudes. Finally, the impact of this planetary wave feature on Polar Mesospheric Clouds (PMC) and Polar Mesospheric Summer Echoes (PMSE) will be discussed.

  17. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  18. The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Abbasi, R.

    2010-05-11

    The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.

  19. The energy spectrum of atmospheric neutrinos between 2 and 200 TeV with the AMANDA-II detector

    Science.gov (United States)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; De Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.

    2010-08-01

    The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.

  20. Foundations of planetary quarantine.

    Science.gov (United States)

    Hall, L. B.; Lyle, R. G.

    1971-01-01

    Discussion of some of the problems in microbiology and engineering involved in the implementation of planetary quarantine. It is shown that the solutions require new knowledge in both disciplines for success at low cost in terms of both monetary outlay and man's further exploration of the planets. A related problem exists in that engineers are not accustomed to the wide variation of biological data and microbiologists must learn to work and think in more exact terms. Those responsible for formulating or influencing national and international policies must walk a tightrope with delicate balance between unnecessarily stringent requirements for planetary quarantine on the one hand and prevention of contamination on the other. The success of planetary quarantine measures can be assured only by rigorous measures, each checked, rechecked, and triple-checked to make sure that no errors have been made and that no factor has been overlooked.

  1. The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - II. Horizontal and Temporal Averaging and Spectral Line Formation

    CERN Document Server

    Magic, Zazralt; Hayek, Wolfgang; Asplund, Martin

    2013-01-01

    We study the implications of averaging methods with different reference depth scales for 3D hydrodynamical model atmo- spheres computed with the Stagger-code. The temporally and spatially averaged (hereafter denoted as ) models are explored in the light of local thermodynamic equilibrium (LTE) spectral line formation by comparing spectrum calculations using full 3D atmosphere structures with those from averages. We explore methods for computing mean stratifications from the Stagger-grid time-dependent 3D radiative hydro- dynamical atmosphere models by considering four different reference depth scales (geometrical depth, column-mass density, and two optical depth scales). Furthermore, we investigate the influence of alternative averages (logarithmic or enforced hydrostatic equilibrium, flux-weighted temperatures). For the line formation we compute curves of growth for Fe i and Fe ii lines in LTE . The resulting stratifications for the four reference depth scales can be considerably different. We find typica...

  2. Cosmological aspects of planetary habitability

    CERN Document Server

    Shchekinov, Yu A; Murthy, J

    2014-01-01

    The habitable zone (HZ) is defined as the region around a star where a planet can support liquid water on its surface, which, together with an oxygen atmosphere, is presumed to be necessary (and sufficient) to develop and sustain life on the planet. Currently, about twenty potentially habitable planets are listed. The most intriguing question driving all these studies is whether planets within habitable zones host extraterrestrial life. It is implicitly assumed that a planet in the habitable zone bears biota. However along with the two usual indicators of habitability, an oxygen atmosphere and liquid water on the surface, an additional one -- the age --- has to be taken into account when the question of the existence of life (or even a simple biota) on a planet is addressed. The importance of planetary age for the existence of life as we know it follows from the fact that the primary process, the photosynthesis, is endothermic with an activation energy higher than temperatures in habitable zones. Therefore on...

  3. The planetary scientist's companion

    CERN Document Server

    Lodders, Katharina

    1998-01-01

    A comprehensive and practical book of facts and data about the Sun, planets, asteroids, comets, meteorites, the Kuiper belt and Centaur objects in our solar system. Also covered are properties of nearby stars, the interstellar medium, and extra-solar planetary systems.

  4. Catalogues of planetary nebulae.

    Science.gov (United States)

    Acker, A.

    Firstly, the general requirements concerning catalogues are studied for planetary nebulae, in particular concerning the objects to be included in a catalogue of PN, their denominations, followed by reflexions about the afterlife and comuterized versions of a catalogue. Then, the basic elements constituting a catalogue of PN are analyzed, and the available data are looked at each time.

  5. Planetary ring systems

    CERN Document Server

    Miner, Ellis D; Cuzzi, Jeffrey N

    2007-01-01

    This is the most comprehensive and up-to-date book on the topic of planetary rings systems yet written. The book is written in a style that is easily accessible to the interested non expert. Each chapter includes notes, references, figures and tables.

  6. Planetary rings - Theory

    Science.gov (United States)

    Borderies, Nicole

    1989-01-01

    Theoretical models of planetary-ring dynamics are examined in a brief analytical review. The mathematical description of streamlines and streamline interactions is outlined; the redistribution of angular momentum due to collisions between particles is explained; and problems in the modeling of broad, narrow, and arc rings are discussed.

  7. Organic chemistry in Titan's atmosphere

    Science.gov (United States)

    Scattergood, T.

    1982-01-01

    Laboratory photochemical simulations and other types of chemical simulations are discussed. The chemistry of methane, which is the major known constituent of Titan's atmosphere was examined with stress on what can be learned from photochemistry and particle irradiation. The composition of dust that comprises the haze layer was determined. Isotope fractionation in planetary atmospheres is also discussed.

  8. Detection of CO in the atmosphere of the hot Jupiter HD 189733b

    Directory of Open Access Journals (Sweden)

    Barnes John R.

    2013-04-01

    Full Text Available With time-series spectroscopic observations taken with the Near Infrared Spectrometer (NIRSPEC at Keck II, we investigated the atmosphere of the close orbiting transiting extrasolar giant planet, HD 189733b. In paticular, we intended to measure the dense absorption line forest around 2.3 micron, which is produced by carbon monoxide (CO. CO is expected to be present in the planetary atmosphere, although no detection of this molecule has been claimed yet. We analyzed the NIRSPEC data with cross-correlation and detect CO absorption in the day-side spectrum of HD 189733b at the known planetary radial velocity semi-amplitude with 99.54% (2.8σ confidence.

  9. Trends and variability of planetary wave activity in the stratosphere in a changing climate

    Science.gov (United States)

    Küchelbacher, Lisa; Wüst, Sabine; Bittner, Michael

    2017-04-01

    Planetary waves are global scale waves in the lower and middle atmosphere which lead to a more or less periodic change of weather patterns in the middle latitudes. This already indicates that planetary waves couple atmospheric layers and can lead to extreme weather events. Climate change is supposed cause changes of planetary wave activity. The question is whether the planetary wave activity has already changed during the last 40 years and -if so - if this can be attributed to a possible weakening of the meridional temperature gradient. To check this we calculated a dynamical activity index (DAI) that serves as a measure for the planetary wave activity based on total ozone column measurements and ERA-Interim temperatures. We found that the DAI based on total ozone column measurements is not reliable for quantifying long term changes in planetary wave activity. Despite we found the ERA-DAI trustworthy. The planetary wave activity has already changed, but significantly only in the stratosphere. The change of the planetary wave activity with highest wavenumbers turned out to be strongest. We also found that also multi-decadal periodic oscillations might have an impact on the wave activity. We especially looked into the consequences of a changing planetary activity into the occurrence of stratospheric warmings and we found evidence that the observed change in the temporal occurrence of stratospheric warmings might be coupled to the detected change in planetary wave activity.

  10. Lunar and Planetary Webcam User's Guide

    CERN Document Server

    Mobberley, Martin

    2006-01-01

    Inexpensive webcams are revolutionizing imaging in amateur astronomy by providing an affordable alternative to cooled-chip astronomical CCD cameras, for photographing the brighter astronomical objects. Webcams – costing only a few tens of dollars – are capable of more advanced high resolution work than "normal" digital cameras because their rapid image download speed can freeze fine planetary details, even through the Earth's turbulent atmosphere. Also, their simple construction makes it easy to remove the lens, allowing them to be used at high power at the projected focus of an astronomical telescope. Webcams also connect direct to a PC, so that software can be used to "stack" multiple images, providing a stunning increase in image quality. In the Lunar and Planetary Webcam User’s Guide Martin Mobberley de-mystifies the jargon of webcams and computer processing, and provides detailed hints and tips for imaging the Sun, Moon and planets with a webcam. He looks at each observing target separately, descri...

  11. The Influence of Volcanic Aerosols on Planetary Habitability

    Science.gov (United States)

    Chen, Howard; Horton, Daniel Ethan

    2017-01-01

    On rocky planetary bodies such as Proxima Centuri b, the detection of sulphate aerosols may indicate volcanism and tectonic activity; ingredients hypothesized to be necessary for planetary habitability. However, due to the effect of atmospheric aerosols on a planet’s energy balance, coupled with eruption constituent and frequency uncertainties, the potential impact of volcanic activity on planetary habitability remains unresolved. Here, we employ multi-column climate models in conjunction with a parameter space approach to test the effect of volcanic aerosols on planetary climate with various climate sensitivities. Preliminary results indicate that volcanic activity could provide a means of extending the inner edge of the habitable zone (IHZ), depending on eruption constituents and frequency. Previous work using transit spectra simulations have demonstrated the possibility of detecting transient aerosols of volcanic origin. Our work investigates the range of habitability implications detection of such aerosols would imply.

  12. The Role of Planetary Data System Archive Standards in International Planetary Data Archives

    Science.gov (United States)

    Guinness, Edward; Slavney, Susan; Beebe, Reta; Crichton, Daniel

    A major objective of NASA's Planetary Data System (PDS) is to efficiently archive and make accessible digital data produced by NASA's planetary missions, research programs, and data analysis programs. The PDS is comprised of a federation of groups known as nodes, with each node focused on archiving and managing planetary data from a given science discipline. PDS nodes include Atmospheres, Geosciences, Small Bodies (asteroids, comets, and dust), Rings, Planetary Plasma Interactions, and Imaging. There are also support nodes for engineering, radio science, and ancillary data, such as geometry information. The PDS archives include space-borne, ground-based, and laboratory experiment data from several decades of NASA exploration of comets, asteroids, moons, and planets. PDS archives are peer-reviewed, welldocumented, and accessible online via web sites, catalogs, and other user-interfaces that provide search and retrieval capabilities. Current holdings within the PDS online repositories total approximately 50 TB of data. Over the next few years, the PDS is planning for a rapid expansion in the volume of data being delivered to its archives. The archive standards developed by the PDS are crucial elements for producing planetary data archives that are consistent across missions and planetary science disciplines and that yield archives that are useable by the planetary research community. These standards encompass the full range of archiving needs. They include standards for the format of data products and the metadata needed to detail how observations were made. They also specify how data products and ancillary information such as documentation, calibration, and geometric information are packaged into data sets. The PDS standards are documented in its Planetary Science Data Dictionary and in its Standards Reference Document and Archive Preparation Guide. The PDS standards are being used to design and implement data archives for current and future NASA planetary missions

  13. Atmosphere expansion and mass loss of close-orbit giant exoplanets heated by stellar XUV. I. Modeling of hydrodynamic escape of upper atmospheric material

    Energy Technology Data Exchange (ETDEWEB)

    Shaikhislamov, I. F. [Institute of Laser Physics SB RAS, Novosibirsk (Russian Federation); Khodachenko, M. L.; Sasunov, Yu. L.; Lammer, H.; Kislyakova, K. G. [Space Research Institute, Austrian Acad. Sci., Graz (Austria); Erkaev, N. V., E-mail: maxim.khodachenko@oeaw.ac.at [Institute of Computational Modelling, SB RAS, Krasnoyarsk (Russian Federation)

    2014-11-10

    In the present series of papers we propose a consistent description of the mass loss process. To study in a comprehensive way the effects of the intrinsic magnetic field of a close-orbit giant exoplanet (a so-called hot Jupiter) on atmospheric material escape and the formation of a planetary inner magnetosphere, we start with a hydrodynamic model of an upper atmosphere expansion in this paper. While considering a simple hydrogen atmosphere model, we focus on the self-consistent inclusion of the effects of radiative heating and ionization of the atmospheric gas with its consequent expansion in the outer space. Primary attention is paid to an investigation of the role of the specific conditions at the inner and outer boundaries of the simulation domain, under which different regimes of material escape (free and restricted flow) are formed. A comparative study is performed of different processes, such as X-ray and ultraviolet (XUV) heating, material ionization and recombination, H{sub 3}{sup +} cooling, adiabatic and Lyα cooling, and Lyα reabsorption. We confirm the basic consistency of the outcomes of our modeling with the results of other hydrodynamic models of expanding planetary atmospheres. In particular, we determine that, under the typical conditions of an orbital distance of 0.05 AU around a Sun-type star, a hot Jupiter plasma envelope may reach maximum temperatures up to ∼9000 K with a hydrodynamic escape speed of ∼9 km s{sup –1}, resulting in mass loss rates of ∼(4-7) · 10{sup 10} g s{sup –1}. In the range of the considered stellar-planetary parameters and XUV fluxes, that is close to the mass loss in the energy-limited case. The inclusion of planetary intrinsic magnetic fields in the model is a subject of the follow-up paper (Paper II).

  14. Atmospheric corrections of colour images of case I waters - a review. Of case II waters - a review

    Energy Technology Data Exchange (ETDEWEB)

    Pozdnyakov, D. [Nansen International Environmental and Remote Sensing Center, St. Petersburg (Russian Federation); Bakan, S.; Grassl, H. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2000-07-01

    Discussed are the basic approaches reported in literature for atmospheric correction of airborne/spaceborne multispectral (visible to near infrared) images of clear waters pertaining to open ocean conditions, i.e. case I waters according to Morel's classification. The extent of applicability and inherent limitations of such approaches are analyzed and the persisting problems identified. (orig.)

  15. A new synthetic library of the Near-Infrared CaII triplet indices. I.Index Definition, Calibration and Relations with stellar atmospheric parameters

    CERN Document Server

    Du, Wei; Zhao, Yong-Heng

    2011-01-01

    Adopting the SPECTRUM package, we have synthesized a set of 2,890 Near-InfraRed (NIR) synthetic spectra with a resolution and wavelength sampling similar to the SDSS and the forthcoming LAMOST spectra. During the synthesis, we have applied the `New grids of ATLAS9 Model Atmosphere' to provide a grid of local thermodynamic equilibrium (LTE) model atmospheres. This synthetic stellar library is composed of 1,350 solor scaled abundance (SSA) and 1,530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR CaII triplet indices and an index CaT as the sum of the three. Then, these defined indices have been automatically measured on the synthetic spectra and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of alpha-element enhancement on the so-defined CaII indices, we have compared indices measured on the SSA spectra with those on the NSSA ones at the same terns of stellar parameters (Teff, log ...

  16. The Solar Spectral Irradiance as a Function of the Mg II Index for Atmosphere and Climate Modelling

    Science.gov (United States)

    Thuillier, Gerard; DeLand, Matthew; Shapiro, Alexander; Schmutz, Werner; Bolsee, David; Melo, Stella

    2011-01-01

    In this paper we present a new method to reconstruct the solar spectrum irradiance in the Ly alpha-400 nm region, and its variability, based on the Mg II index and neutron monitor. Measurements of the solar spectral irradiance available in the literature have been made with different instruments at different times and different spectral ranges. However, climate studies require harmonized data sets. This new approach has the advantage of being independent of the absolute calibration and aging of the instruments. First, the Mg II index is derived using solar spectra from Ly alpha (121 nm) to 410 nm measured from 1978 to 2010 by several space missions. The variability of the spectra with respect to a chosen reference spectrum as a function of time and wavelength is scaled to the derived Mg II index. The set of coefficients expressing the spectral variability can be applied to the chosen reference spectrum to reconstruct the solar spectra within a given time frame or Mg II index values. The accuracy of this method is estimated using two approaches: by direct comparison with particular cases where solar spectra are available from independent measurements, and by calculating the standard deviation between the measured spectra and their reconstruction. From direct comparisons with measurements we obtain an accuracy of about 1 to 2 %, which degrades towards Ly alpha. In a further step, we extend our solar spectral irradiance reconstruction back to the Maunder Minimum introducing the relationship between the Mg II index and the neutron monitor data. Consistent measurements of the Mg II index are not available prior to 1978. However, we observe that over the last three solar cycles, the Mg II index shows strong correlation with the modulation potential determined from the neutron monitor data. Assuming that this correlation can be applied to the past, we reconstruct the Mg II index from the modulation potential back to the Maunder Minimum, and obtain the corresponding solar

  17. Forming different planetary systems

    Institute of Scientific and Technical Information of China (English)

    Ji-Lin Zhou; Ji-Wei Xie; Hui-Gen Liu; Hui Zhang; Yi-Sui Sun

    2012-01-01

    With the increasing number of detected exoplanet samples,the statistical properties of planetary systems have become much clearer.In this review,we summarize the major statistical results that have been revealed mainly by radial velocity and transiting observations,and try to interpret them within the scope of the classical core-accretion scenario of planet formation,especially in the formation of different orbital architectures for planetary systems around main sequence stars.Based on the different possible formation routes for different planet systems,we tentatively classify them into three major catalogs:hot Jupiter systems,standard systems and distant giant planet systems.The standard systems can be further categorized into three sub-types under different circumstances:solar-like systems,hot Super-Earth systems,and subgiant planet systems.We also review the theory of planet detection and formation in binary systems as well as planets in star clusters.

  18. Measuring and interpreting X-ray fluorescence from planetary surfaces.

    Science.gov (United States)

    Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

    2008-11-15

    As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

  19. ESA Planetary Science Archive

    Science.gov (United States)

    Arviset, C.; Dowson, J.; Ortiz, I.; Parrilla, E.; Salgado, J.; Zender, J.

    2007-10-01

    The (ESA Planetary Science Archive {http://www.rssd.esa.int/psa} (PSA) hosts all the data from ESA's planetary missions into a single archive. It currently contains data from the Giotto, Mars Express, Rosetta, and Huygens spacecraft, some ground-based observations, and will host data from the Smart-1, Venus Express, and BepiColombo spacecraft in the future. Based on the NASA Planetary Data Systems (PDS) data dictionary, all datasets provided by the instrument teams are scientifically peer-reviewed and technically validated by software before being ingested into the Archive. Based on a modular and flexible architecture, the PSA offers a classical user-interface based on input fields, with powerful query and display possibilities. Data can be downloaded directly or through a more detailed shopping basket. Furthermore, a map-based interface is available to access Mars Express data without requiring any knowledge of the mission. Interoperability between the ESA PSA and the NASA PDS archives is also in progress, re-using concepts and experience gained from existing IVOA protocols. Prototypes are being developed to provide functionalities like GoogleMars, allowing access to both ESA PSA and NASA PDS data.

  20. Galactic planetary science.

    Science.gov (United States)

    Tinetti, Giovanna

    2014-04-28

    Planetary science beyond the boundaries of our Solar System is today in its infancy. Until a couple of decades ago, the detailed investigation of the planetary properties was restricted to objects orbiting inside the Kuiper Belt. Today, we cannot ignore that the number of known planets has increased by two orders of magnitude nor that these planets resemble anything but the objects present in our own Solar System. Whether this fact is the result of a selection bias induced by the kind of techniques used to discover new planets--mainly radial velocity and transit--or simply the proof that the Solar System is a rarity in the Milky Way, we do not know yet. What is clear, though, is that the Solar System has failed to be the paradigm not only in our Galaxy but even 'just' in the solar neighbourhood. This finding, although unsettling, forces us to reconsider our knowledge of planets under a different light and perhaps question a few of the theoretical pillars on which we base our current 'understanding'. The next decade will be critical to advance in what we should perhaps call Galactic planetary science. In this paper, I review highlights and pitfalls of our current knowledge of this topic and elaborate on how this knowledge might arguably evolve in the next decade. More critically, I identify what should be the mandatory scientific and technical steps to be taken in this fascinating journey of remote exploration of planets in our Galaxy.

  1. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II – gas phase reactions of organic species

    OpenAIRE

    2006-01-01

    This article, the second in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Organic species, which were last published in 1999, and were updated on the IUPAC website in late 2002, and subsequently during the preparation of this article. The article consists of a summary table of the recommended rate coefficients, containing the...

  2. GrayStar: A Web application for pedagogical stellar atmosphere and spectral line modelling and visualisation II: Methods

    CERN Document Server

    Short, C Ian

    2014-01-01

    GrayStar is a stellar atmospheric and spectral line modelling, post-processing, and visualisation code, suitable for classroom demonstrations and laboratory-style assignments, that has been developed in Java and deployed in JavaScript and HTML. The only software needed to compute models and post-processed observables, and to visualise the resulting atmospheric structure and observables, is a common Web browser. Therefore, the code will run on any common PC or related X86 (-64) computer of the type that typically serves classroom data projectors, is found in undergraduate computer laboratories, or that students themselves own, including those with highly portable form-factors such as net-books and tablets. The user requires no experience with compiling source code, reading data files, or using plotting packages. More advanced students can view the JavaScript source code using the developer tools provided by common Web browsers. The code is based on the approximate gray atmospheric solution and runs quickly eno...

  3. Prebiotic synthesis in atmospheres containing CH4, CO, and CO2. II. Hydrogen cyanide, formaldehyde and ammonia.

    Science.gov (United States)

    Schlesinger, G; Miller, S L

    1983-01-01

    The electric discharge synthesis of HCN, H2CO, NH3 and urea has been investigated using various mixtures of CH4, CO, CO2, N2, NH3, H2O, and H2. HCN and H2CO were each synthesized in yields as high as 10% from CH4 as a carbon source. Similar yields were obtained from CO when H2/CO greater than 1.0 and from CO2 when H2/CO2 greater than 2.0. At H2/CO2 less than 1.0 the yields fall off drastically. Good yields of NH3 (0.7 to 5%) and fair yields of urea (0.02 to 0.63%) based on nitrogen were also obtained. The directly synthesized NH3 together with the NH3 obtained from the hydrolysis of HCN, nitriles and urea could have been a major source of ammonia in the atmosphere and oceans of the primitive earth. These results show that prebiotic syntheses from HCN and H2CO to give products such as purines and sugars and some amino acids could have occurred in primitive atmospheres containing CO and CO2 provided the H2/CO and H2/CO2 ratios were greater than about 1.0. Methane containing atmospheres give comparable quantities of HCN and H2CO, and are superior in the synthesis of amino acids.

  4. Atmospheric Circulation of Exoplanets

    CERN Document Server

    Showman, Adam P; Menou, Kristen

    2009-01-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric d...

  5. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II – gas phase reactions of organic species

    Directory of Open Access Journals (Sweden)

    R. Atkinson

    2006-01-01

    Full Text Available This article, the second in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Organic species, which were last published in 1999, and were updated on the IUPAC website in late 2002, and subsequently during the preparation of this article. The article consists of a summary table of the recommended rate coefficients, containing the recommended kinetic parameters for the evaluated reactions, and eight appendices containing the data sheets, which provide information upon which the recommendations are made.

  6. SOFIA-EXES Mid-IR Observations of [Fe II] Emission from the Extended Atmosphere of Betelgeuse

    Science.gov (United States)

    Harper, G. M.; DeWitt, C.; Richter, M. J.; Greathouse, T. K.; Ryde, N.; Guinan, E. F.; O’Gorman, E.; Vacca, W. D.

    2017-02-01

    We present a NASA-DLR SOFIA-Echelon Cross Echelle Spectrograph (EXES) and NASA Infrared Telescope Facility-Texas Echelon Cross Echelle Spectrograph (TEXES) mid-IR R≃ {{50,000}} spectral study of forbidden Fe ii transitions in the early-type M supergiants, Betelgeuse (α Ori: M2 Iab) and Antares (α Sco: M1 Iab + B3 V). With EXES, we spectrally resolve the ground term [Fe ii] 25.99 μm (a{}6{D}J=7/2{--9/2}: {E}{up}=540 K) emission from Betelgeuse. We find a small centroid blueshift of 1.9 ± 0.4 {km} {{{s}}}-1 that is a significant fraction (20%) of the current epoch wind speed, with a FWHM of 14.3 ± 0.1 {km} {{{s}}}-1. The TEXES observations of [Fe ii] 17.94 μm (a{}4{F}J=7/2-9/2: {E}{up}={{3400}} K) show a broader FWHM of 19.1 ± 0.2 {km} {{{s}}}-1, consistent with previous observations, and a small redshift of 1.6 ± 0.6 {km} {{{s}}}-1 with respect to the adopted stellar center-of-mass velocity of {V}{CoM}=20.9+/- 0.3 {km} {{{s}}}-1. To produce [Fe ii] 25.99 μm blueshifts of 20% wind speed requires that the emission arises closer to the star than existing thermal models for α Ori’s circumstellar envelope predict. This implies a more rapid wind cooling to below 500 K within 10{R}* ({θ }* =44 mas, dist = 200 pc) of the star, where the wind has also reached a significant fraction of the maximum wind speed. The line width is consistent with the turbulence in the outflow being close to the hydrogen sound speed. EXES observations of [Fe ii] 22.90 μm (a{}4{D}J=5/2{--7/2}: {E}{up}={{11,700}} K) reveal no emission from either star. These findings confirm the dominance of cool plasma in the mixed region where hot chromospheric plasma emits copiously in the UV, and they also constrain the wind heating produced by the poorly understood mechanisms that drive stellar outflows from these low variability and weak-dust signature stars.

  7. Atlas of monochromatic images of planetary nebulae

    CERN Document Server

    Weidmann, W A; Valdarenas, R R Vena; Ahumada, J A; Volpe, M G; Mudrik, A

    2016-01-01

    We present an atlas of more than one hundred original images of planetary nebulae (PNe). These images were taken in a narrow-band filter centred on the nebular emission of the [N II] during several observing campaigns using two moderate-aperture telescopes, at the Complejo Astron\\'omico El Leoncito (CASLEO), and the Estaci\\'on Astrof\\'isica de Bosque Alegre (EABA), both in Argentina. The data provided by this atlas represent one of the most extensive image surveys of PNe in [N II]. We compare the new images with those available in the literature, and briefly describe all cases in which our [N II] images reveal new and interesting structures.

  8. Planetary Magnetic Fields: Planetary Interiors and Habitability W. M. Keck Institute for Space Studies Report

    Science.gov (United States)

    Lazio, T. Joseph; Shkolnik, Evgenya; Hallinan, Gregg

    2017-05-01

    The W. M. Keck Institute for Space Studies (KISS) sponsored the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection.There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process.We review the findings from the Study, including potential mission concepts that emerged and recent developments toward one of the mission concepts, a space-based radio wavelength array. There was an identification of that radio wavelength observations would likely be key to making significant progress in this field.We acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study organized by the W. M. Keck

  9. Sonar equations for planetary exploration.

    Science.gov (United States)

    Ainslie, Michael A; Leighton, Timothy G

    2016-08-01

    The set of formulations commonly known as "the sonar equations" have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and localize objects submerged in seawater. The efficacy of the sonar equations, with individual terms evaluated in decibels, is well established in Earth's oceans. The sonar equations have been used in the past for missions to other planets and moons in the solar system, for which they are shown to be less suitable. While it would be preferable to undertake high-fidelity acoustical calculations to support planning, execution, and interpretation of acoustic data from planetary probes, to avoid possible errors for planned missions to such extraterrestrial bodies in future, doing so requires awareness of the pitfalls pointed out in this paper. There is a need to reexamine the assumptions, practices, and calibrations that work well for Earth to ensure that the sonar equations can be accurately applied in combination with the decibel to extraterrestrial scenarios. Examples are given for icy oceans such as exist on Europa and Ganymede, Titan's hydrocarbon lakes, and for the gaseous atmospheres of (for example) Jupiter and Venus.

  10. Modelled Black Carbon Radiative Forcing and Atmospheric Lifetime in AeroCom Phase II Constrained by Aircraft Observations

    Energy Technology Data Exchange (ETDEWEB)

    Samset, B. H.; Myhre, G.; Herber, Andreas; Kondo, Yutaka; Li, Shao-Meng; Moteki, N.; Koike, Makoto; Oshima, N.; Schwarz, Joshua P.; Balkanski, Y.; Bauer, S.; Bellouin, N.; Berntsen, T.; Bian, Huisheng; Chin, M.; Diehl, Thomas; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kirkevag, A.; Lamarque, Jean-Francois; Lin, Guang; Liu, Xiaohong; Penner, Joyce E.; Schulz, M.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, Kostas; Zhang, Kai

    2014-11-27

    Black carbon (BC) aerosols absorb solar radiation, and are generally held to exacerbate global warming through exerting a positive radiative forcing1. However, the total contribution of BC to the ongoing changes in global climate is presently under debate2-8. Both anthropogenic BC emissions and the resulting spatial and temporal distribution of BC concentration are highly uncertain2,9. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood, leading to large estimated uncertainty in BC concentration at high altitudes and far from emission sources10. These uncertainties limit our ability to quantify both the historical, present and future anthropogenic climate impact of BC. Here we compare vertical profiles of BC concentration from four recent aircraft measurement campaigns with 13 state of the art aerosol models, and show that recent assessments may have overestimated present day BC radiative forcing. Further, an atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in transport dominated remote regions. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in the multi-model median direct BC forcing from fossil fuel and biofuel burning over the industrial era.

  11. Universal planetary tectonics (supertectonics)

    Science.gov (United States)

    Kochemasov, G. G.

    2009-04-01

    Universal planetary tectonics (supertectonics) G. Kochemasov IGEM of the Russian Academy of Sciences, Moscow, Russia, kochem.36@mail.ru The wave planetology [1-3 & others] proceeds from the following: "planetary structures are made by orbits and rotations". A uniform reason makes uniform structures. Inertia-gravity waves arising in planetary bodies due to their movements in Keplerian elliptical orbits with periodically changing accelerations warp these bodies in such way that they acquire polyhedron shapes (after interference of standing waves of four directions). Strong Newtonian gravity makes bodies larger than ~400 to 500 km in diameter globular and polyhedra are rarely seen. Only geomorphologic, geologic and geophysical mapping can develop these hidden structures. But small bodies, normally less than ~ 300 to 400 km in diameter, often show parts of the polyhedra, rarely fully developed forms (the asteroid Steins and satellite Amalthea present rather perfect forms of "diamond"). Depending on warping wavelengths (they make harmonics) various Plato's figures superimposed on each other can be distinguished. The fundamental wave 1 produces a tetrahedron, intrinsically dichotomic figure in which a vertex (contraction) always is opposed to a face (expansion). From the recent examples the best is the saturnian northern hexagon (a face) opposed to the southern hurricane (a vertex). The first overtone wave 2 is responsible for creation of structural octahedra. Whole ‘diamonds" and their parts are known [4, 5]. Other overtones produce less developed (because of smaller wave amplitudes) planetary shapes complicating main forms. Thus, the first common structural peculiarity of planetary bodies is their polyhedron nature. Not less important is the second common structural peculiarity. As all globular or smaller more or less isometric bodies rotate, they have an angular momentum. It is inevitably different in tropic and extra-tropic belts having uneven radii or distances to

  12. Robotic Planetary Drill Tests

    Science.gov (United States)

    Glass, Brian J.; Thompson, S.; Paulsen, G.

    2010-01-01

    Several proposed or planned planetary science missions to Mars and other Solar System bodies over the next decade require subsurface access by drilling. This paper discusses the problems of remote robotic drilling, an automation and control architecture based loosely on observed human behaviors in drilling on Earth, and an overview of robotic drilling field test results using this architecture since 2005. Both rotary-drag and rotary-percussive drills are targeted. A hybrid diagnostic approach incorporates heuristics, model-based reasoning and vibration monitoring with neural nets. Ongoing work leads to flight-ready drilling software.

  13. Unveiling shocks in planetary nebulae

    CERN Document Server

    Guerrero, M A; Medina, J J; Luridiana, V; Miranda, L F; Riera, A; Velázquez, P F

    2013-01-01

    The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O III]/Halpha. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrowband [O III] and Halpha images of PNe available in the HST archive to build their [O III]/Halpha ratio maps and to search for regions where this ratio is enhanced. Regions with enhanced [O III]/Halpha emission ratio can be ascribed to two different types of morphological structures: bow-shock structures produced by fast collimated outflows and thin skins enveloping expanding nebular shells. Both collimated outflows and expanding shells are therefore confirmed to generate shocks in PNe. We also find regions with depressed values of the [O III]/Halpha ratio which are found mostly around density bounded PNe, where the local contribution of [N II] emission into the F656N Halpha filter cannot be neglected.

  14. A grid of MARCS model atmospheres for late-type stars. II. S stars and their properties

    Science.gov (United States)

    Van Eck, Sophie; Neyskens, Pieter; Jorissen, Alain; Plez, Bertrand; Edvardsson, Bengt; Eriksson, Kjell; Gustafsson, Bengt; Jørgensen, Uffe Gråe; Nordlund, Åke

    2017-05-01

    S-type stars are late-type giants whose atmospheres are enriched in carbon and s-process elements because of either extrinsic pollution by a binary companion or intrinsic nucleosynthesis and dredge-up on the thermally-pulsing asymptotic giant branch. A grid of MARCS model atmospheres has been computed for S stars, covering the range 2700 ≤ Teff(K) ≤ 4000, 0.50 ≤ C/O ≤ 0.99, 0 ≤ log g ≤ 5, [Fe/H] = 0., -0.5 dex, and [s/Fe] = 0, 1, and 2 dex (where the latter quantity refers to the global overabundance of s-process elements). The MARCS models make use of a new ZrO line list. Synthetic spectra computed from these models are used to derive photometric indices in the Johnson and Geneva systems, as well as TiO and ZrO band strengths. A method is proposed to select the model best matching any given S star, a non-trivial operation since the grid contains more than 3500 models covering a five-dimensional parameter space. The method is based on the comparison between observed and synthetic photometric indices and spectral band strengths, and has been applied on a vast subsample of the Henize sample of S stars. Our results confirm the old claim by Piccirillo (1980, MNRAS, 190, 441) that ZrO bands in warm S stars (Teff>3200 K) are not caused by the C/O ratio being close to unity, as traditionally believed, but rather by some Zr overabundance. The TiO and ZrO band strengths, combined with V-K and J-K photometric indices, are used to select Teff, C/O, [Fe/H] and [s/Fe]. The Geneva U-B1 and B2-V1 indices (or any equivalent) are good at selecting the gravity. The defining spectral features of dwarf S stars are outlined, but none is found among the Henize S stars. More generally, it is found that, at Teff = 3200 K, a change of C/O from 0.5 to 0.99 has a strong impact on V-K (2 mag). Conversely, a range of 2 mag in V-K corresponds to a 200 K shift along the (Teff, V-K) relationship (for a fixed C/O value). Hence, the use of a (Teff, V-K) calibration established for M

  15. Planetary Ices Attenuation Properties

    Science.gov (United States)

    McCarthy, Christine; Castillo-Rogez, Julie C.

    In this chapter, we review the topic of energy dissipation in the context of icy satellites experiencing tidal forcing. We describe the physics of mechanical dissipation, also known as attenuation, in polycrystalline ice and discuss the history of laboratory methods used to measure and understand it. Because many factors - such as microstructure, composition and defect state - can influence rheological behavior, we review what is known about the mechanisms responsible for attenuation in ice and what can be inferred from the properties of rocks, metals and ceramics. Since attenuation measured in the laboratory must be carefully scaled to geologic time and to planetary conditions in order to provide realistic extrapolation, we discuss various mechanical models that have been used, with varying degrees of success, to describe attenuation as a function of forcing frequency and temperature. We review the literature in which these models have been used to describe dissipation in the moons of Jupiter and Saturn. Finally, we address gaps in our present knowledge of planetary ice attenuation and provide suggestions for future inquiry.

  16. Galactic planetary science

    CERN Document Server

    Tinetti, Giovanna

    2014-01-01

    Planetary science beyond the boundaries of our Solar System is today in its infancy. Until a couple of decades ago, the detailed investigation of the planetary properties was restricted to objects orbiting inside the Kuiper Belt. Today, we cannot ignore that the number of known planets has increased by two orders of magnitude nor that these planets resemble anything but the objects present in our own Solar System. Whether this fact is the result of a selection bias induced by the kind of techniques used to discover new planets -mainly radial velocity and transit - or simply the proof that the Solar System is a rarity in the Milky Way, we do not know yet. What is clear, though, is that the Solar System has failed to be the paradigm not only in our Galaxy but even 'just' in the solar neighbourhood. This finding, although unsettling, forces us to reconsider our knowledge of planets under a different light and perhaps question a few of the theoretical pillars on which we base our current 'understanding'. The next...

  17. First theoretical global line lists of ethylene (12C2H4) spectra for the temperature range 50-700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

    Science.gov (United States)

    Rey, M.; Delahaye, T.; Nikitin, A. V.; Tyuterev, Vl. G.

    2016-10-01

    We present the construction of complete and comprehensive ethylene line lists for the temperatures 50-700 K based on accurate ab initio potential and dipole moment surfaces and extensive first-principle calculations. Three lists spanning the [0-6400] cm-1 infrared region were built at T = 80, 160, and 296 K, and two lists in the range [0-5200] cm-1 were built at 500 and 700 K. For each of these five temperatures, we considered possible convergence problems to ensure reliable opacity calculations. Our final list at 700 K was computed up to J = 71 and contains almost 60 million lines for intensities I > 5 × 10-27 cm/molecule. Comparisons with experimental spectra carried out in this study showed that for the most active infrared bands, the accuracy of band centers in our theoretical lists is better on average than 0.3 cm-1, and the integrated absorbance errors in the intervals relevant for spectral analyses are about 1-3%. These lists can be applied to simulations of absorption and emission spectra, radiative and non-LTE processes, and opacity calculations for planetary and astrophysical applications. The lists are freely accessible through the TheoReTS information system at http://theorets.univ-reims.fr and http://theorets.tsu.ru

  18. Seasonal constraints on inferred planetary heat content

    Science.gov (United States)

    McKinnon, Karen A.; Huybers, Peter

    2016-10-01

    Planetary heating can be quantified using top of the atmosphere energy fluxes or through monitoring the heat content of the Earth system. It has been difficult, however, to compare the two methods with each other because of biases in satellite measurements and incomplete spatial coverage of ocean observations. Here we focus on the the seasonal cycle whose amplitude is large relative to satellite biases and observational errors. The seasonal budget can be closed through inferring contributions from high-latitude oceans and marginal seas using the covariance structure of National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM1). In contrast, if these regions are approximated as the average across well-observed regions, the amplitude of the seasonal cycle is overestimated relative to satellite constraints. Analysis of the same CESM1 simulation indicates that complete measurement of the upper ocean would increase the magnitude and precision of interannual trend estimates in ocean heating more than fully measuring the deep ocean.

  19. Planetary Embryo Bow Shocks as a Mechanism for Chondrule Formation

    CERN Document Server

    Mann, Christopher R; Morris, Melissa M

    2016-01-01

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo's eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adia...

  20. Science Case for Planetary Exploration with Planetary CubeSats and SmallSats

    Science.gov (United States)

    Castillo-Rogez, Julie; Raymond, Carol; Jaumann, Ralf; Vane, Gregg; Baker, John

    2016-07-01

    Nano-spacecraft and especially CubeSats are emerging as viable low cost platforms for planetary exploration. Increasing miniaturization of instruments and processing performance enable smart and small packages capable of performing full investigations. While these platforms are limited in terms of payload and lifetime, their form factor and agility enable novel mission architectures and a refreshed relationship to risk. Leveraging a ride with a mothership to access far away destinations can significantly augment the mission science return at relatively low cost. Depending on resources, the mothership may carry several platforms and act as telecom relay for a distributed network or other forms of fractionated architectures. In Summer 2014 an international group of scientists, engineers, and technologists started a study to define investigations to be carried out by nano-spacecrafts. These applications flow down from key science priorities of interest across space agencies: understanding the origin and organization of the Solar system; characterization of planetary processes; assessment of the astrobiological significance of planetary bodies across the Solar system; and retirement of strategic knowledge gaps (SKGs) for Human exploration. This presentation will highlight applications that make the most of the novel architectures introduced by nano-spacecraft. Examples include the low cost reconnaissance of NEOs for science, planetary defense, resource assessment, and SKGs; in situ chemistry measurements (e.g., airless bodies and planetary atmospheres), geophysical network (e.g., magnetic field measurements), coordinated physical and chemical characterization of multiple icy satellites in a giant planet system; and scouting, i.e., risk assessment and site reconnaissance to prepare for close proximity observations of a mothership (e.g., prior to sampling). Acknowledgements: This study is sponsored by the International Academy of Astronautics (IAA). Part of this work is

  1. Planetary Nebulae and How to Observe Them

    CERN Document Server

    Griffiths, Martin

    2012-01-01

    Astronomers' Observing Guides provide up-to-date information for amateur astronomers who want to know all about what is it they are observing. This is the basis of the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments. Planetary Nebulae and How to Observe Them is intended for amateur astronomers who want to concentrate on one of the most beautiful classes of astronomical objects in the sky. This book will help the observer to see these celestial phenomena using telescopes of various apertures. As a Sun-like star reaches the end of its life, its hydrogen fuel starts to run out. It collapses until helium nuclei begin nuclear fusion, whereupon the star begins to pulsate, each pulsation throwing off a layer of the star's atmosphere. Eventually the atmosphere has all been ejected as an expanding cloud of gas, the star's core is exposed and ultraviolet photons cause the shell of gas to glow brilliantly - that's planetary ...

  2. Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    André, Nicolas; Grande, Manuel

    2016-04-01

    Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI) will include an entirely new Virtual Access Service, WP5 VA1 "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. VA1 will make five entirely new 'toolkits' accessible to the research community and to industrial partners planning for space missions: a general planetary space weather toolkit, as well as three toolkits dedicated to the following key planetary environments: Mars (in support ExoMars), comets (building on the expected success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUICE mission to be launched in 2022). This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather in the tools and models available within the partner institutes. It will also create a novel event-diary toolkit aiming at predicting and detecting planetary events like meteor showers and impacts. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. So WP10 JRA4 "Planetary Space Weather Services" (PSWS) will provide the additional research and tailoring required to apply them for these purposes. The overall objectives of this Joint Research Aactivities will be to review, test, improve and adapt methods and tools available within the partner institutes in order to make prototype planetary event and space weather services operational in

  3. Earth as an Exoplanet: Lessons in Recognizing Planetary Habitability

    Science.gov (United States)

    Meadows, Victoria; Robinson, Tyler; Misra, Amit; Ennico, Kimberly; Sparks, William B.; Claire, Mark; Crisp, David; Schwieterman, Edward; Bussey, D. Ben J.; Breiner, Jonathan

    2015-01-01

    Earth will always be our best-studied example of a habitable world. While extrasolar planets are unlikely to look exactly like Earth, they may share key characteristics, such as oceans, clouds and surface inhomogeneity. Earth's globally-averaged characteristics can therefore help us to recognize planetary habitability in data-limited exoplanet observations. One of the most straightforward ways to detect habitability will be via detection of 'glint', specular reflectance from an ocean (Robinson et al., 2010). Other methods include undertaking a census of atmospheric greenhouse gases, or attempting to measure planetary surface temperature and pressure, to determine if liquid water would be feasible on the planetary surface. Here we present recent research on detecting planetary habitability, led by the NASA Astrobiology Institute's Virtual Planetary Laboratory Team. This work includes a collaboration with the NASA Lunar Science Institute on the detection of ocean glint and ozone absorption using Lunar Crater Observation and Sensing Satellite (LCROSS) Earth observations (Robinson et al., 2014). This data/model comparison provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths. We find that the VPL spectral Earth model is in excellent agreement with the LCROSS Earth data, and can be used to reliably predict Earth's appearance at a range of phases relevant to exoplanet observations. Determining atmospheric surface pressure and temperature directly for a potentially habitable planet will be challenging due to the lack of spatial-resolution, presence of clouds, and difficulty in spectrally detecting many bulk constituents of terrestrial atmospheres. Additionally, Rayleigh scattering can be masked by absorbing gases and absorption from the underlying surface. However, new techniques using molecular dimers of oxygen (Misra et al., 2014) and nitrogen

  4. Calculation of infrared limb emission by ozone in the terrestrial middle atmosphere. I - Source functions. II - Emission calculations

    Science.gov (United States)

    Mlynczak, Martin G.; Drayson, S. Roland

    1990-01-01

    The departure from LTE in the vibration-rotation bands of ozone in the middle atmosphere is analyzed using two statistical equilibrium models: the energy gap model and the simplified single model. The diurnal variations in the fundamental band source functions nu(1) and nu(3) is determined by the diurnal change in the rate of ozone photolysis by the solar radiation. Source functions are presented for the vibration-rotation bands of ozone that emit in the 9-11-micron spectral interval, over an altitude range of 1-110 km. Results are also reported of the evaluation of the radiative transfer equation incorporating these source functions and energy level populations. Using the results of the two statistical equilibrium models, calculations are carried out of the spectrally integrated limb radiance for the limb viewing geometry for daytime conditions. Results indicate that the interpretation of the measurements of spectrally integrated limb radiance from ozone will be greatly complicated by the breakdown of LTE in the vibration-rotational bands of ozone.

  5. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola II : Supra-Terahertz Windows and Model Fitting

    Science.gov (United States)

    Matsushita, Satoki; Matsuo, Hiroshi; Pardo, Juan R.; Radford, Simon J. E.

    1999-10-01

    A second observing run aimed to measure the millimeter and submillimeter-wave (150-1500 GHz or 2 mm-200 mu m) atmospheric opacity was carried out with a Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above sea level in northern Chile. We obtained high transmission spectra, showing up to ~ 67% transmission at submillimeter-wave windows. The observed spectra can be well modeled by newly developed radiative-transfer calculations. Correlations between 220 GHz and submillimeter-wave opacities were reanalized, including the new data set. The results show almost identical trends as the ones resulting from the first measurements. We also identified supra-terahertz windows (located around 1035 GHz, 1350 GHz, and 1500 GHz), which could not be seen in our first measurements. Opacity correlations between the 220 GHz and these new windows are derived for the first time. Combined with a statistical study of the 225 GHz opacity data of the Chajnantor site (7 km apart from Pampa la Bola), it is estimated that submillimeter-wave observations can be done with zenith opacity less than 1.0 (at the most transparent frequency in those windows) for about 50% of the winter season.

  6. Planetary Doppler Imaging

    Science.gov (United States)

    Murphy, N.; Jefferies, S.; Hart, M.; Hubbard, W. B.; Showman, A. P.; Hernandez, G.; Rudd, L.

    2014-12-01

    Determining the internal structure of the solar system's gas and ice giant planets is key to understanding their formation and evolution (Hubbard et al., 1999, 2002, Guillot 2005), and in turn the formation and evolution of the solar system. While internal structure can be constrained theoretically, measurements of internal density distributions are needed to uncover the details of the deep interior where significant ambiguities exist. To date the interiors of giant planets have been probed by measuring gravitational moments using spacecraft passing close to, or in orbit around the planet. Gravity measurements are effective in determining structure in the outer envelope of a planet, and also probing dynamics (e.g. the Cassini and Juno missions), but are less effective in probing deep structure or the presence of discrete boundaries. A promising technique for overcoming this limitation is planetary seismology (analogous to helioseismology in the solar case), postulated by Vorontsov, 1976. Using trapped pressure waves to probe giant planet interiors allows insight into the density and temperature distribution (via the sound speed) down to the planetary core, and is also sensitive to sharp boundaries, for example at the molecular to metallic hydrogen transition or at the core-envelope interface. Detecting such boundaries is not only important in understanding the overall structure of the planet, but also has implications for our understanding of the basic properties of matter at extreme pressures. Recent Doppler measurements of Jupiter by Gaulme et al (2011) claimed a promising detection of trapped oscillations, while Hedman and Nicholson (2013) have shown that trapped waves in Saturn cause detectable perturbations in Saturn's C ring. Both these papers have fueled interest in using seismology as a tool for studying the solar system's giant planets. To fully exploit planetary seismology as a tool for understanding giant planet structure, measurements need to be made

  7. Application of high resolution land use and land cover data for atmospheric modeling in the Houston-Galveston Metropolitan area: Part II. Air quality simulation results

    Science.gov (United States)

    Cheng, Fang-Yi; Kim, Soontae; Byun, Daewon W.

    In the companion paper, we showed that MM5 simulation using a satellite-derived high resolution Texas Forest Service (TFS) land use and land cover (LULC) data set (M2), compared to the MM5 results with the default USGS-LULC (M1), improved representation of the complicated features of the atmospheric planetary boundary layer (PBL) in the Houston ship channel (HSC) area, where large industrial emission sources are concentrated. In the present paper, the study is extended to investigate these effects on air quality simulations. Two emission inputs, namely E1 and E2, are prepared with the M1 and M2 meteorology data, respectively, to reflect the differences in the point source plume rise estimates while keeping the biogenic and mobile emissions the same. Air quality simulations were performed with CMAQ using the M1E1 and M2E2 inputs. The simulation results demonstrate the importance of utilizing high resolution LULC data. In the default LULC data, the HSC area was classified as grass land cover, and MM5 predicted confined mixing, resulting in over-prediction of ozone (O 3) precursors, such as NO x (NO plus NO 2), and highly reactive volatile organic compounds (HRVOC) species, including ethylene and propylene, over the HSC area. In the TFS data, the area was classified as the impervious "urban" land use and MM5 predicted enhanced mixing of the precursor species, leading to better agreements with measurements. The high resolution LULC also resolves the location of water body near the HSC more accurately, predicting shallower PBL heights than the default LULC during daytime. With favorable wind conditions, the O 3 precursors were transported from the HSC emission source towards the area, trapping the pollutants in a confined shallow mixing layer that occasionally led to a rapid photochemical production of O 3. The above comparison includes the changes in both meteorological and plume-rise emissions inputs. We performed two additional CMAQ simulations using the same

  8. The Stagger-grid: A grid of 3D stellar atmosphere models. II. Horizontal and temporal averaging and spectral line formation

    Science.gov (United States)

    Magic, Z.; Collet, R.; Hayek, W.; Asplund, M.

    2013-12-01

    Aims: We study the implications of averaging methods with different reference depth scales for 3D hydrodynamical model atmospheres computed with the Stagger-code. The temporally and spatially averaged (hereafter denoted as ⟨3D⟩) models are explored in the light of local thermodynamic equilibrium (LTE) spectral line formation by comparing spectrum calculations using full 3D atmosphere structures with those from ⟨3D⟩ averages. Methods: We explored methods for computing mean ⟨3D⟩ stratifications from the Stagger-grid time-dependent 3D radiative hydrodynamical atmosphere models by considering four different reference depth scales (geometrical depth, column-mass density, and two optical depth scales). Furthermore, we investigated the influence of alternative averages (logarithmic, enforced hydrostatic equilibrium, flux-weighted temperatures). For the line formation we computed curves of growth for Fe i and Fe ii lines in LTE. Results: The resulting ⟨3D⟩ stratifications for the four reference depth scales can be very different. We typically find that in the upper atmosphere and in the superadiabatic region just below the optical surface, where the temperature and density fluctuations are highest, the differences become considerable and increase for higher Teff, lower log g, and lower [Fe / H]. The differential comparison of spectral line formation shows distinctive differences depending on which ⟨3D⟩ model is applied. The averages over layers of constant column-mass density yield the best mean ⟨3D⟩ representation of the full 3D models for LTE line formation, while the averages on layers at constant geometrical height are the least appropriate. Unexpectedly, the usually preferred averages over layers of constant optical depth are prone to increasing interference by reversed granulation towards higher effective temperature, in particular at low metallicity. Appendix A is available in electronic form at http://www.aanda.orgMean ⟨3D⟩ models are

  9. Planetary internal structures

    CERN Document Server

    Baraffe, I; Fortney, J; Sotin, C

    2014-01-01

    This chapter reviews the most recent advancements on the topic of terrestrial and giant planet interiors, including Solar System and extrasolar objects. Starting from an observed mass-radius diagram for known planets in the Universe, we will discuss the various types of planets appearing in this diagram and describe internal structures for each type. The review will summarize the status of theoretical and experimental works performed in the field of equation of states (EOS) for materials relevant to planetary interiors and will address the main theoretical and experimental uncertainties and challenges. It will discuss the impact of new EOS on interior structures and bulk composition determination. We will discuss important dynamical processes which strongly impact the interior and evolutionary properties of planets (e.g plate tectonics, semiconvection) and describe non standard models recently suggested for our giant planets. We will address the case of short-period, strongly irradiated exoplanets and critica...

  10. High-resolution spectroscopy of central stars of planetary nebulae - LSS 1362

    Science.gov (United States)

    Heber, U.; Werner, K.; Drilling, J. S.

    1988-01-01

    High resolution spectra of the hot sdO star LSS 1362, a central star of a planetary nebula, are analyzed by means of model atmosphere techniques. Improved NLTE model atmospheres based on the newly developed 'accelerated lambda iteration' method are used. The very high effective temperature (100000 K) derived previously from the UV energy distribution is confirmed. The surface gravity (log g = 5.3) and a normal helium abundance are derived. A mass of 0.65 solar mass and a luminosity of 10 exp 3.9 solar luminosities result from a comparison with evolutionary tracks. The distance is 1.1 kpc and the nebula has a diameter of about 0.25 pc to 0.5 pc. Weak photospheric emission lines of He II, CIV, Nv, and O v are detected. These lines are slightly blue-shifted with respect to the absorption line spectrum which is regarded as evidence for an atmospheric velocity field. It is conjectured that the observed broadening of the metal lines (25 km/s) may be caused by the velocity field rather than by rotation.

  11. High Pressure Atmospheric Sampling Inlet System for Venus or the Gas Giants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a miniaturized high pressure atmospheric sampling inlet system for sample acquisition in extreme planetary environments,...

  12. Distinguishing Between Stellar and Planetary Companions With Phase Monitoring

    CERN Document Server

    Kane, Stephen R

    2012-01-01

    Exoplanets which are detected using the radial velocity technique have a well-known ambiguity of their true mass, caused by the unknown inclination of the planetary orbit with respect to the plane of the sky. Constraints on the inclination are aided by astrometric follow-up in rare cases or, in ideal situations, through subsequent detection of a planetary transit. As the predicted inclination decreases, the mass of the companion increases leading to a change in the predicted properties. Here we investigate the changes in the mass, radius, and atmospheric properties as the inclination pushes the companion from the planetary into the brown dwarf and finally low-mass star regimes. We determine the resulting detectable photometric signatures in the predicted phase variation as the companion changes properties and becomes self-luminous. We apply this to the HD 114762 and HD 162020 systems for which the minimum masses of the known companions places them at the deuterium-burning limit.

  13. New approaches to planetary exploration - Spacecraft and information systems design

    Science.gov (United States)

    Diaz, A. V.; Neugebauer, M.; Stuart, J.; Miller, R. B.

    1983-01-01

    Approaches are recommended for use by the NASA Solar System Exploration Committee (SSEC) in lowering the costs of planetary missions. The inclusion of off-the-shelf hardware, i.e., configurations currently in use for earth orbits and constructed on a nearly assembly-line basis, is suggested. Alterations would be necessary for the thermal control, power supply, telecommunications equipment, and attitude sensing in order to be serviceable as a planetary observer spacecraft. New technology can be developed only when cost reduction for the entire mission would be realized. The employment of lower-cost boost motors, or even integrated boost motors, for the transfer out of earth orbit is indicated, as is the development of instruments that do not redundantly gather the same data as previous planetary missions. Missions under consideration include a Mars geoscience climatology Orbiter, a lunar geoscience Orbiter, a near-earth asteroid rendezvous, a Mars aeronomy Orbiter, and a Venus atmospheric probe.

  14. Planetary and Interplanetary Environmental Models for Radiation Analysis

    Science.gov (United States)

    DeAngelis, G.; Cucinotta, F. A.

    2005-01-01

    The essence of environmental modeling is presented as suited for radiation analysis purposes. The variables of fundamental importance for radiation environmental assessment are discussed. The characterization is performed by dividing modeling into three areas, namely the interplanetary medium, the circumplanetary environment, and the planetary or satellite surface. In the first area, the galactic cosmic rays (GCR) and their modulation by the heliospheric magnetic field as well as and solar particle events (SPE) are considered, in the second area the magnetospheres are taken into account, and in the third area the effect of the planetary environment is also considered. Planetary surfaces and atmospheres are modeled based on results from the most recent targeted spacecraft. The results are coupled with suited visualization techniques and radiation transport models in support of trade studies of health risks for future exploration missions.

  15. Modified-atmosphere storage under subatmospheric pressure and beef quality: II. Color, drip, cooking loss, sarcomere length, and tenderness.

    Science.gov (United States)

    Smulders, F J M; Hiesberger, J; Hofbauer, P; Dögl, B; Dransfield, E

    2006-09-01

    Beef has a requirement for refrigerated storage up to 14 d to achieve adequate aging and a tender product. To achieve this aging with little spoilage and no surface drying, vacuum packaging is attractive, because it is inherently simple and offers a clear indication to the packer when the process has failed or there is risk of spoilage. However, there is increasing pressure on the meat industry to limit the use of packaging materials in view of their cost and the cost involved in their recovery and recycling. The purpose of this report was to evaluate an alternative storage system in containers using modified atmospheres at reduced pressure (approximately 25 kPa). The quality of the meat for both container- and vacuum-packed treatments was measured during chilled storage for up to 3 wk. Storage time had the most significant effect on quality characteristics, irrespective of the packaging method. Storage in containers under a 70%N2:30%CO2 gas mixture gave characteristics similar to beef stored under vacuum. Storage in containers under 100% CO2 produced less drip loss than under 70%N2:30%CO2, but generally container storage produced 3 times as much drip loss as vacuum packaging. Shear force of the LM was unaffected by the type of packaging, and at d 2 after slaughter (i.e., before the storage trial was begun), sarcomere lengths of muscles intended for container storage were similar to those destined for vacuum storage. During the packaging treatment, the comparison between the storage systems was always done within 1 animal using one carcass-half for container storage and the other half for vacuum packaging; all bulls were shackled from the left hindleg during bleeding. The majority of the muscles from the left sides had lower shear force values than those from the right sides at the earlier storage times (2 and 9 d after slaughter) but had similar values after longer storage (16 and 23 d after slaughter). This is the first report that shackling beef carcasses from

  16. Exoplanet atmospheres physical processes

    CERN Document Server

    Seager, Sara

    2010-01-01

    Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introdu

  17. The global kinematics of the Dumbbell planetary nebula (NGC 6853, M27, PN G060.8-03.6)

    CERN Document Server

    Meaburn, J; Christopoulou, P E; Goudis, C D; Bryce, M; López, J A

    2005-01-01

    Spatially resolved profiles of the HeII 6560 A, Halpha and [N II] 6548 & 6584 A nebular emission lines have been obtained in two orthogonal long cuts over the Dumbbell planetary nebula. The central HeII 6560 A emitting volume of the bright dumbbell structure is shown to be particularly inert with an expansion velocity of = 25 km/s. The present results are compared with currents models for the creation of planetary nebulae.

  18. Planetary Spectrum Generator (PSG): An Online Tool to Synthesize Spectra of Comets, Small Bodies, and (Exo)Planets

    Science.gov (United States)

    Villanueva, G. L.; Mandell, A.; Protopapa, S.; Faggi, S.; Smith, M. D.; Wolff, M.; Hewagama, T.; Mumma, M. J.

    2017-02-01

    The Planetary Spectrum Generator is an online tool for synthesizing planetary spectra (atmospheres and surfaces) in a broad range of wavelengths (0.1 μm to 100 mm, UV/Vis/near-IR/IR/far-IR/THz/sub-mm/radio) for any observatory, orbiter, or lander.

  19. Proceedings of the 40th Lunar and Planetary Science Conference

    Science.gov (United States)

    2009-01-01

    The 40th Lunar and Planetary Science Conference included sessions on: Phoenix: Exploration of the Martian Arctic; Origin and Early Evolution of the Moon; Comet Wild 2: Mineralogy and More; Astrobiology: Meteorites, Microbes, Hydrous Habitats, and Irradiated Ices; Phoenix: Soil, Chemistry, and Habitability; Planetary Differentiation; Presolar Grains: Structures and Origins; SPECIAL SESSION: Venus Atmosphere: Venus Express and Future Missions; Mars Polar Caps: Past and Present; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part I; 5 Early Nebula Processes and Models; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Cosmic Gymnasts; Mars: Ground Ice and Climate Change; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part II; Chondrite Parent-Body Processes; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Salubrious Surfaces; SNC Meteorites; Ancient Martian Crust: Primary Mineralogy and Aqueous Alteration; SPECIAL SESSION: Messenger at Mercury: A Global Perspective on the Innermost Planet; CAIs and Chondrules: Records of Early Solar System Processes; Small Bodies: Shapes of Things to Come; Sulfur on Mars: Rocks, Soils, and Cycling Processes; Mercury: Evolution and Tectonics; Venus Geology, Volcanism, Tectonics, and Resurfacing; Asteroid-Meteorite Connections; Impacts I: Models and Experiments; Solar Wind and Genesis: Measurements and Interpretation; Mars: Aqueous Processes; Magmatic Volatiles and Eruptive Conditions of Lunar Basalts; Comparative Planetology; Interstellar Matter: Origins and Relationships; Impacts II: Craters and Ejecta Mars: Tectonics and Dynamics; Mars Analogs I: Geological; Exploring the Diversity of Lunar Lithologies with Sample Analyses and Remote Sensing; Chondrite Accretion and Early History; Science Instruments for the Mars Science Lander; . Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Volcanism; Early Solar System Chronology

  20. Proceedings of the 40th Lunar and Planetary Science Conference

    Science.gov (United States)

    2009-01-01

    The 40th Lunar and Planetary Science Conference included sessions on: Phoenix: Exploration of the Martian Arctic; Origin and Early Evolution of the Moon; Comet Wild 2: Mineralogy and More; Astrobiology: Meteorites, Microbes, Hydrous Habitats, and Irradiated Ices; Phoenix: Soil, Chemistry, and Habitability; Planetary Differentiation; Presolar Grains: Structures and Origins; SPECIAL SESSION: Venus Atmosphere: Venus Express and Future Missions; Mars Polar Caps: Past and Present; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part I; 5 Early Nebula Processes and Models; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Cosmic Gymnasts; Mars: Ground Ice and Climate Change; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part II; Chondrite Parent-Body Processes; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Salubrious Surfaces; SNC Meteorites; Ancient Martian Crust: Primary Mineralogy and Aqueous Alteration; SPECIAL SESSION: Messenger at Mercury: A Global Perspective on the Innermost Planet; CAIs and Chondrules: Records of Early Solar System Processes; Small Bodies: Shapes of Things to Come; Sulfur on Mars: Rocks, Soils, and Cycling Processes; Mercury: Evolution and Tectonics; Venus Geology, Volcanism, Tectonics, and Resurfacing; Asteroid-Meteorite Connections; Impacts I: Models and Experiments; Solar Wind and Genesis: Measurements and Interpretation; Mars: Aqueous Processes; Magmatic Volatiles and Eruptive Conditions of Lunar Basalts; Comparative Planetology; Interstellar Matter: Origins and Relationships; Impacts II: Craters and Ejecta Mars: Tectonics and Dynamics; Mars Analogs I: Geological; Exploring the Diversity of Lunar Lithologies with Sample Analyses and Remote Sensing; Chondrite Accretion and Early History; Science Instruments for the Mars Science Lander; . Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Volcanism; Early Solar System Chronology

  1. Simultaneous Subaru/MAGNUM Observations of Extrasolar Planetary Transits

    Science.gov (United States)

    Narita, N.

    2007-07-01

    We introduce our project of simultaneous Subaru/MAGNUM observations of extrasolar planetary transits, designed for (i) transmission spectroscopy in order to search for absorption features due to planetary exospheres, and (ii) precise radial velocity measurements in order to measure the Rossiter-McLaughlin effect. Our observing strategy of extrasolar planetary transits is to conduct simultaneous spectroscopic/photometric (optical+IR) observations, using the HDS of the Subaru 8.2-m telescope at Mauna Kea and the MAGNUM 2-m telescope at Haleakala, both in Hawaii. The simultaneous photometric monitoring will eliminate any uncertainty due to orbital ephemeris in our results, and it will also allow an independent determination of the transit depth and the limb-darkening parameters. In this manuscript, we detail our ability of observations to characterize transiting extrasolar planets, and also introduce previous studies, current status and prospects of the project.

  2. Solar System Processes Underlying Planetary Formation, Geodynamics, and the Georeactor

    CERN Document Server

    Herndon, J M

    2006-01-01

    Only three processes, operant during the formation of the Solar System, are responsible for the diversity of matter in the Solar System and are directly responsible for planetary internal-structures, including planetocentric nuclear fission reactors, and for dynamical processes, including and especially, geodynamics. These processes are: (i) Low-pressure, low-temperature condensation from solar matter in the remote reaches of the Solar System or in the interstellar medium; (ii) High-pressure, high-temperature condensation from solar matter associated with planetary-formation by raining out from the interiors of giant-gaseous protoplanets, and; (iii) Stripping of the primordial volatile components from the inner portion of the Solar System by super-intense solar wind associated with T-Tauri phase mass-ejections, presumably during the thermonuclear ignition of the Sun. As described herein, these processes lead logically, in a causally related manner, to a coherent vision of planetary formation with profound imp...

  3. Planetary Protection Constraints For Planetary Exploration and Exobiology

    Science.gov (United States)

    Debus, A.; Bonneville, R.; Viso, M.

    According to the article IX of the OUTER SPACE TREATY (London / Washington January 27., 1967) and in the frame of extraterrestrial missions, it is required to preserve planets and Earth from contamination. For ethical, safety and scientific reasons, the space agencies have to comply with the Outer Space Treaty and to take into account the related planetary protection Cospar recommendations. Planetary protection takes also into account the protection of exobiological science, because the results of life detection experimentations could have impacts on planetary protection regulations. The validation of their results depends strongly of how the samples have been collected, stored and analyzed, and particularly of their biological and organic cleanliness. Any risk of contamination by organic materials, chemical coumpounds and by terrestrial microorganisms must be avoided. A large number of missions is presently scheduled, particularly on Mars, in order to search for life or traces of past life. In the frame of such missions, CNES is building a planetary protection organization in order handle and to take in charge all tasks linked to science and engineering concerned by planetary protection. Taking into account CNES past experience in planetary protection related to the Mars 96 mission, its planned participation in exobiological missions with NASA as well as its works and involvement in Cospar activities, this paper will present the main requirements in order to avoid celestial bodies biological contamination, focussing on Mars and including Earth, and to protect exobiological science.

  4. Planetary cratering mechanics

    Science.gov (United States)

    O'Keefe, John D.; Ahrens, Thomas J.

    1993-09-01

    The objective of this study was to obtain a quantitative understanding of the cratering process over a broad range of conditions. Our approach was to numerically compute the evolution of impact induced flow fields and calculate the time histories of the key measures of crater geometry (e.g., depth, diameter, lip height) for variations in planetary gravity (0 to 109 cm/s2), material strength (0 to 2400 kbar), and impactor radius (0.05 to 5000 km). These results were used to establish the values of the open parameters in the scaling laws of Holsapple and Schmidt (1987). We describe the impact process in terms of four regimes: (1) penetration, (2) inertial, (3) terminal, and (4) relaxation. During the penetration regime, the depth of impactor penetration grows linearly for dimensionless times τ=(Ut/a)5.1, the crater grows at a slower rate until it is arrested by either strength or gravitational forces. In this regime, the increase of crater depth, d, and diameter, D, normalized by projectile radius is given by d/a=1.3 (Ut/a)0.36 and D/a=2.0(Ut/a)0.36. For strength-dominated craters, growth stops at the end of the inertial regime, which occurs at τ=0.33 (Yeff/ρU2)-0.78, where Yeff is the effective planetary crustal strength. The effective strength can be reduced from the ambient strength by fracturing and shear band melting (e.g., formation of pseudo-tachylites). In gravity-dominated craters, growth stops when the gravitational forces dominate over the inertial forces, which occurs at τ=0.92 (ga/U2)-0.61. In the strength and gravity regimes, the maximum depth of penetration is dp/a=0.84 (Y/ρ U2)-0.28 and dp/a=1.2 (ga/U2)-0.22, respectively. The transition from simple bowl-shaped craters to complex-shaped craters occurs when gravity starts to dominate over strength in the cratering process. The diameter for this transition to occur is given by Dt=9.0 Y/ρg, and thus scales as g-1 for planetary surfaces when strength is not strain-rate dependent. This scaling result

  5. Magnetic Helicity and Planetary Dynamos

    Science.gov (United States)

    Shebalin, John V.

    2012-01-01

    A model planetary dynamo based on the Boussinesq approximation along with homogeneous boundary conditions is considered. A statistical theory describing a large-scale MHD dynamo is found, in which magnetic helicity is the critical parameter

  6. What characterizes planetary space weather?

    OpenAIRE

    2014-01-01

    International audience; Space weather has become a mature discipline for the Earth space environment. With increasing efforts in space exploration, it is becoming more and more necessary to understand the space environments of bodies other than Earth. This is the background for an emerging aspect of the space weather discipline: planetary space weather. In this article, we explore what characterizes planetary space weather, using some examples throughout the solar system. We consider energy s...

  7. Molecular studies of Planetary Nebulae

    OpenAIRE

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition ...

  8. Planetary Vital Signs

    Science.gov (United States)

    Kennel, Charles; Briggs, Stephen; Victor, David

    2016-07-01

    The climate is beginning to behave in unusual ways. The global temperature reached unprecedented highs in 2015 and 2016, which led climatologists to predict an enormous El Nino that would cure California's record drought. It did not happen the way they expected. That tells us just how unreliable temperature has become as an indicator of important aspects of climate change. The world needs to go beyond global temperature to a set of planetary vital signs. Politicians should not over focus policy on one indicator. They need to look at the balance of evidence. A coalition of scientists and policy makers should start to develop vital signs at once, since they should be ready at the entry into force of the Paris Agreement in 2020. But vital signs are only the beginning. The world needs to learn how to use the vast knowledge we will be acquiring about climate change and its impacts. Is it not time to use all the tools at hand- observations from space and ground networks; demographic, economic and societal measures; big data statistical techniques; and numerical models-to inform politicians, managers, and the public of the evolving risks of climate change at global, regional, and local scales? Should we not think in advance of an always-on social and information network that provides decision-ready knowledge to those who hold the responsibility to act, wherever they are, at times of their choosing?

  9. Pressure-dependent water absorption cross sections for exoplanets and other atmospheres

    CERN Document Server

    Barton, Emma J; Yurchenko, Sergei N; Tennyson, Jonathan; Dudaryonok, Anna S; Lavrentieva, Nina N

    2016-01-01

    Many atmospheres (cool stars, brown dwarfs, giant planets, extrasolar planets) are predominately composed of molecular hydrogen and helium. H$_2{}^{16}$O is one of the best measured molecules in extrasolar planetary atmospheres to date and a major compound in the atmospheres of brown-dwarfs and oxygen-rich cool stars, yet the scope of experimental and theoretical studies on the pressure broadening of water vapour lines by collision with hydrogen and helium remains limited. Theoretical H$_2$- and He-broadening parameters of water vapour lines (rotational quantum number $J$ up to 50) are obtained for temperatures in the range 300 - 2000 K. Two approaches for calculation of line widths were used: (i) the averaged energy difference method and (ii) the empirical expression for $J$\\p $J$\\pp-dependence. Voigt profiles based on these widths and the BT2 line list are used to generate high resolution ($\\Delta \\tilde{\

  10. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    Science.gov (United States)

    Yates, Jack S.; Palmer, Paul I.; Biller, Beth; Cockell, Charles S.

    2017-02-01

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. To illustrate our model, we use a cool Y dwarf atmosphere, such as WISE J085510.83-0714442.5, whose 4.5-5.2 μm spectrum shows absorption features consistent with water vapor and clouds. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment, we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Based on a previously defined statistical approach, we infer that there are of the order of 109 cool Y brown dwarfs in the Milky Way, and likely a few tens of these objects are within 10 pc from Earth. Our work also has implications for exploring life in the atmospheres of temperate gas giants. Consideration of the habitable volumes in planetary atmospheres significantly increases the volume of habitable space in the galaxy.

  11. Star Surface Polluted by Planetary Debris

    Science.gov (United States)

    2007-07-01

    normal planet-hosting stars. "We find that evolved stars are not enriched in metals, even when hosting planets," says Pasquini. "Thus, the anomalies found in planet-hosting stars seem to disappear when they get older and puff up!" Looking at the various options, the astronomers conclude that the most likely explanation lies in the difference in the structure between red giants and solar-like stars: the size of the convective zone, the region where all the gas is completely mixed. In the Sun, this convective zone comprises only 2% of the star's mass. But in red giants, the convective zone is huge, encompassing 35 times more mass. The polluting material would thus be 35 times more diluted in a red giant than in a solar-like star. "Although the interpretation of the data is not straightforward, the simplest explanation is that solar-like stars appear metal-rich because of the pollution of their atmospheres," says co-author Artie Hatzes, Director of the Thüringer Landessternwarte Tautenburg (Germany) where some of the data were obtained. When the star was still surrounded by a proto-planetary disc, material enriched in more heavy elements would fall onto the star, thereby polluting its surface. The metal excess produced by this pollution, while visible in the thin atmospheres of solar-like stars, is completely diluted in the extended, massive atmospheres of the giants.

  12. Dynamics of large-scale atmospheric circulation over Siberia using NCEP/DOE AMIP-II reanalysis data and synoptic maps

    Science.gov (United States)

    Podnebesnykh, Nataliya

    2014-05-01

    Dynamics of large-scale atmospheric circulation over Siberia using NCEP/DOE AMIP-II reanalysis data and synoptic maps Podnebesnykh N.V., Ippolitov I.I. Institute of Monitoring of Climatic and Ecological Systems SB RAS 634055, Tomsk, 10/3 Academichesky Ave. In this paper a comparative analysis of cyclones and anticyclones characteristics, which defined circulation conditions over Siberia (50-70°W, 60-110°N) in the period of 1976-2011 was carried out using synoptic maps and NCEP/DOE AMIP II reanalysis data. The analysis has shown the ambiguous relationships in the results of the comparison. The number of cyclones and anticyclones, obtained from synoptic maps exceeds on an average by 1.2 times the number of pressure formations, determined from reanalysis data. This tendency is, probably, due to the fact that in general NCEP/DOE AMIP-II reanalysis data, like other reanalysis datasets, represents large pressure systems better than small systems. Such result is in a good agreement with studies of other authors. The pressure in the cyclonic centers varies from 996.7 to 1006.0 hPa using synoptic maps and from 992.4 to 1000.3 hPa using reanalysis data. As for anticyclones the pressure in the centers varies from 1026.3 to 1034.2 hPa and 1022.9-1028.1 hPa according to synoptic maps and reanalysis data, respectively. The average pressure in the cyclonic centers for the period of 1976-2006 was 1000.9 hPa (σ = 2.0 hPa) according to synoptic maps, and 996.6 hPa (σ = 1.9 hPa) according to reanalysis data. The average pressure in the anticyclonic centers was 1029.9 hPa (σ = 1.8 hPa) and 1026.0 hPa (σ = 1.4 hPa), respectively. Therefore, cyclones, obtained by synoptic maps, are not deep and anticyclones are more intensive in comparison with pressure formations from reanalysis data. The average annual number of days with cyclones over the territory of under study is less than that with anticyclones, i.e. during the period of 1976-2006 anticyclonic weather conditions dominated

  13. Heliophysics: Active Stars, their Astrospheres, and Impacts on Planetary Environments

    Science.gov (United States)

    Schrijver, C. J.; Bagenal, F.; Sojka, J. J.

    2016-04-01

    Preface; 1. Introduction Carolus J. Schrijver, Frances Bagenal and Jan J. Sojka; 2. Solar explosive activity throughout the evolution of the Solar System Rachel Osten; 3. Astrospheres, stellar winds, and the interstellar medium Brian Wood and Jeffrey L. Linsky; 4. Effects of stellar eruptions throughout astrospheres Ofer Cohen; 5. Characteristics of planetary systems Debra Fischer and Ji Wang; 6. Planetary dynamos: updates and new frontiers Sabine Stanley; 7. Climates of terrestrial planets David Brain; 8. Upper atmospheres of the giant planets Luke Moore, Tom Stallard and Marina Garland; 9. Aeronomy of terrestrial upper atmospheres David E. Siskind and Stephen W. Bougher; 10. Moons, asteroids, and comets interacting with their surroundings Margaret G. Kivelson; 11. Dusty plasmas Mihály Horányi; 12. Energetic-particle environments in the Solar System Norbert Krupp; 13. Heliophysics with radio scintillation and occultation Mario M. Bisi; Appendix 1. Authors and editors; List of illustrations; List of tables; References; Index.

  14. Plate tectonics and planetary habitability: current status and future challenges.

    Science.gov (United States)

    Korenaga, Jun

    2012-07-01

    Plate tectonics is one of the major factors affecting the potential habitability of a terrestrial planet. The physics of plate tectonics is, however, still far from being complete, leading to considerable uncertainty when discussing planetary habitability. Here, I summarize recent developments on the evolution of plate tectonics on Earth, which suggest a radically new view on Earth dynamics: convection in the mantle has been speeding up despite its secular cooling, and the operation of plate tectonics has been facilitated throughout Earth's history by the gradual subduction of water into an initially dry mantle. The role of plate tectonics in planetary habitability through its influence on atmospheric evolution is still difficult to quantify, and, to this end, it will be vital to better understand a coupled core-mantle-atmosphere system in the context of solar system evolution. © 2012 New York Academy of Sciences.

  15. Planetary Geologic Mapping Handbook - 2009

    Science.gov (United States)

    Tanaka, K. L.; Skinner, J. A.; Hare, T. M.

    2009-01-01

    Geologic maps present, in an historical context, fundamental syntheses of interpretations of the materials, landforms, structures, and processes that characterize planetary surfaces and shallow subsurfaces (e.g., Varnes, 1974). Such maps also provide a contextual framework for summarizing and evaluating thematic research for a given region or body. In planetary exploration, for example, geologic maps are used for specialized investigations such as targeting regions of interest for data collection and for characterizing sites for landed missions. Whereas most modern terrestrial geologic maps are constructed from regional views provided by remote sensing data and supplemented in detail by field-based observations and measurements, planetary maps have been largely based on analyses of orbital photography. For planetary bodies in particular, geologic maps commonly represent a snapshot of a surface, because they are based on available information at a time when new data are still being acquired. Thus the field of planetary geologic mapping has been evolving rapidly to embrace the use of new data and modern technology and to accommodate the growing needs of planetary exploration. Planetary geologic maps have been published by the U.S. Geological Survey (USGS) since 1962 (Hackman, 1962). Over this time, numerous maps of several planetary bodies have been prepared at a variety of scales and projections using the best available image and topographic bases. Early geologic map bases commonly consisted of hand-mosaicked photographs or airbrushed shaded-relief views and geologic linework was manually drafted using mylar bases and ink drafting pens. Map publishing required a tedious process of scribing, color peel-coat preparation, typesetting, and photo-laboratory work. Beginning in the 1990s, inexpensive computing, display capability and user-friendly illustration software allowed maps to be drawn using digital tools rather than pen and ink, and mylar bases became obsolete

  16. Lessons learned from planetary entry probe missions

    Science.gov (United States)

    Niemann, Hasso; Atreya, Sushil K.; Kasprzak, Wayne

    Probing the atmospheres and surfaces of the planets and their moons with fast moving entry probes has been a very useful and essential technique to obtain in situ or quasi in situ scientific data (ground truth) which could not otherwise be obtained from fly by or orbiter only missions and where balloon, aircraft or lander missions are too complex and too costly. Planetary entry probe missions have been conducted successfully on Venus, Mars, Jupiter and Titan after having been first demonstrated in the Earth's atmosphere. Future planetary missions should also include more entry probe missions back to Venus and to the outer planets. The success of and science returns from past missions, the need for more and unique data, and a continuously advancing technology generate confidence that future missions will be even more successful with respect to science return and technical performance. There are, however, unique challenges associated with entry probe missions and with building instruments for an entry probe, as compared to orbiters, landers, or rovers. Conditions during atmospheric entry are extreme. There are operating time constraints due to the usually short duration of the probe descent, and the instruments experience rapid environmental changes in temperature and pressure. In addition, there are resource limitations, i.e. mass, power, size and bandwidth. Because of the protective heat shield and the high acceleration the probe experiences during entry, the ratio of payload to total probe mass is usually much smaller than in other missions. Finally, the demands on the instrument design are determined in large part by conditions (pressure, temperature, composition) unique to the particular body under study, and as a result, there is no one-size-fits-all instrument for an atmospheric probe. Many of these requirements are more easily met by miniaturizing the probe instrumentation and consequently reducing the required size of the probe. Improved heat shield

  17. Jim Pollack's Contributions to Planetary Science

    Science.gov (United States)

    Haberle, Robert M.; Cuzzi, Jeffrey N. (Technical Monitor)

    1994-01-01

    Jim Pollack was an extraordinary scientist. Since receiving his Ph.D. from Harvard in 1965, he published hundreds of papers in scientific journals, encyclopedias, popular magazines, and books. The sheer volume of this kind of productivity is impressive enough, but when considering the diversity and detail of his work, these accomplishments seem almost superhuman. Jim studied and wrote about every planet in the solar system. For, this he was perhaps the most distinguished planetary scientist of his generation. He successfully identified the composition of Saturn's rings and Venus's clouds. With his collaborators, he created the first detailed models for the formation of the outer planets, and the general circulation of the Martian atmosphere. His interest in Mars dust storms provided a foundation for the "nuclear winter" theory that ultimately helped shape foreign policy in the cold war era. Jim's creative talents brought him many awards including the Kuiper Award of the Division of Planetary Sciences, the Leo Szilard Award of the American Physical Society, H. Julian Allen award of the Ames Research Center, and several NASA medals for exceptional scientific achievement.

  18. FITTING PHOTOIONIZATION MODELS TO PLANETARY NEBULAE

    Directory of Open Access Journals (Sweden)

    J. Bohigas

    2009-01-01

    Full Text Available Good to excellent photoionization models based on the Cloudy code were obtained for 13 out of 19 spectra of planetary nebulae. The two most important assumptions are that the photoionizing continuum is a Rauch model star, with gravity set by the condition that the stellar mass must be 1 M , and density is constant and determined from the observed [S II]6717/6731 ratio. The temperature and luminosity of the central star, the inner radius of the nebula and the abundance of carbon are treated as free parameters in each model run, destined to obtain the best possible t to the relative intensities of He II 4686, [O III]5007 and [N II]6584. Observed and modeled nebular temperatures derived from [N II] (6548+6584 /5755 agree within 10%, but models usually underestimate temperatures found from [O III] (4959+5007 /4363, more so when the slit does not cover the in-depth extent of the ionized region. Helium, nitrogen, oxygen, neon, sulfur and argon model abundances are uncertain at the 15%, 15%, 10%, 7%, 30% and 7% level. It is shown that neon abundance in PNe has been consistently overestimated, and an alternative ionization correction factor is recommended.

  19. Nanotube-based Sensors and Systems for Outer Planetary Exploration

    Science.gov (United States)

    Noca, F.; Hunt, B. D.; Hoenk, M. E.; Choi, D.; Kowalczyk, R.; Williams, R.; Xu, J.; Koumoutsakos, P.

    2001-01-01

    Direct sensing and processing at the nanometer scale offer NASA the opportunity to expand its capabilities in deep space exploration, particularly for the search for signatures of life, the analysis of planetary oceans and atmospheres, and communications systems. Carbon nanotubes, with their unique mechanical, electrical, and radiation-tolerant properties, are a promising tool for this exploration. We are developing devices based on carbon nanotubes, including sensors, actuators, and oscillators. Additional information is contained in the original extended abstract.

  20. The OpenPlanetary initiative

    Science.gov (United States)

    Manaud, Nicolas; Rossi, Angelo Pio; Hare, Trent; Aye, Michael; Galluzzi, Valentina; van Gasselt, Stephan; Martinez, Santa; McAuliffe, Jonathan; Million, Chase; Nass, Andrea; Zinzi, Angelo

    2016-10-01

    "Open" has become attached to several concepts: science, data, and software are some of the most obvious. It is already common practice within the planetary science community to share spacecraft missions data freely and openly [1]. However, this is not historically the case for software tools, source code, and derived data sets, which are often reproduced independently by multiple individuals and groups. Sharing data, tools and overall knowledge would increase scientific return and benefits [e.g. 2], and recent projects and initiatives are helping toward this goal [e.g. 3,4,5,6].OpenPlanetary is a bottom-up initiative to address the need of the planetary science community for sharing ideas and collaborating on common planetary research and data analysis problems, new challenges, and opportunities. It started from an initial participants effort to stay connected and share information related to and beyond the ESA's first Planetary GIS Workshop [7]. It then continued during the 2nd (US) Planetary Data Workshop [8], and aggregated more people.Our objective is to build an online distributed framework enabling open collaborations within the planetary science community. We aim to co-create, curate and publish resource materials and data sets; to organise online events, to support community-based projects development; and to offer a real-time communication channel at and between conferences and workshops.We will present our current framework and resources, developing projects and ideas, and solicit for feedback and participation. OpenPlanetary is intended for research and education professionals: scientists, engineers, designers, teachers and students, as well as the general public that includes enthusiasts and citizen scientists. All are welcome to join and contribute at openplanetary.co[1] International Planetary Data Alliance, planetarydata.org. [2] Nosek et al (2015), dx.doi.org/10.1126/science.aab2374. [3] Erard S. et al. (2016), EGU2016-17527. [4] Proposal for a PDS

  1. The chemical composition of three planetary nebulae in the Magellanic Clouds

    Science.gov (United States)

    Dufour, R. J.; Killen, R. M.

    1977-01-01

    The paper studies the detailed spectral characteristics of the planetary nebulae N97 and N153 in the Large Magellanic Cloud (LMC), the planetary nebula N67 in the Small Magellanic Cloud (SMC), and the small H II regions N9, N61, and N81 in the SMC. Electron temperatures and densities for each nebula are derived from emission-line strengths determined by photographic spectrophotometry, and relative abundances are estimated for H, He, N, O, Ne, Ar, and S. The results show that: (1) N67 has a 60% overabundance in He/H while N97 and N153 have approximately normal He/H values; (2) all three planetaries have N/H values comparable to those of galactic planetaries but substantially higher than found in the H II regions of their respective Cloud; (3) the O/H values in the planetaries are similar to or lower than those in the H II regions of the respective Cloud; (4) the O/Ne, O/S, and O/Ar ratios in the two LMC planetaries are comparable to those in galactic planetaries; (5) the compositions of the small H II regions in the SMC are nearly identical to those of previously studied large H II regions in the same Cloud; and (6) the He/H ratio of the interstellar gas in the SMC is about 25% less than that in the Galaxy. It is concluded that most of the N abundance in both Clouds arose from nucleosynthesis sources other than planetary nebulae.

  2. NASA Planetary Visualization Tool

    Science.gov (United States)

    Hogan, P.; Kim, R.

    2004-12-01

    NASA World Wind allows one to zoom from satellite altitude into any place on Earth, leveraging the combination of high resolution LandSat imagery and SRTM elevation data to experience Earth in visually rich 3D, just as if they were really there. NASA World Wind combines LandSat 7 imagery with Shuttle Radar Topography Mission (SRTM) elevation data, for a dramatic view of the Earth at eye level. Users can literally fly across the world's terrain from any location in any direction. Particular focus was put into the ease of usability so people of all ages can enjoy World Wind. All one needs to control World Wind is a two button mouse. Additional guides and features can be accessed though a simplified menu. Navigation is automated with single clicks of a mouse as well as the ability to type in any location and automatically zoom to it. NASA World Wind was designed to run on recent PC hardware with the same technology used by today's 3D video games. NASA World Wind delivers the NASA Blue Marble, spectacular true-color imagery of the entire Earth at 1-kilometer-per-pixel. Using NASA World Wind, you can continue to zoom past Blue Marble resolution to seamlessly experience the extremely detailed mosaic of LandSat 7 data at an impressive 15-meters-per-pixel resolution. NASA World Wind also delivers other color bands such as the infrared spectrum. The NASA Scientific Visualization Studio at Goddard Space Flight Center (GSFC) has produced a set of visually intense animations that demonstrate a variety of subjects such as hurricane dynamics and seasonal changes across the globe. NASA World Wind takes these animations and plays them directly on the world. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) produces a set of time relevant planetary imagery that's updated every day. MODIS catalogs fires, floods, dust, smoke, storms and volcanic activity. NASA World Wind produces an easily customized view of this information and marks them directly on the globe. When one

  3. Planetary Geophysics and Tectonics

    Science.gov (United States)

    Zuber, Maria

    2005-01-01

    The broad objective of this work is to improve understanding of the internal structures and thermal and stress histories of the solid planets by combining results from analytical and computational modeling, and geophysical data analysis of gravity, topography and tectonic surface structures. During the past year we performed two quite independent studies in the attempt to explain the Mariner 10 magnetic observations of Mercury. In the first we revisited the possibility of crustal remanence by studying the conditions under which one could break symmetry inherent in Runcorn's model of a uniformly magnetized shell to produce a remanent signal with a dipolar form. In the second we applied a thin shell dynamo model to evaluate the range of intensity/structure for which such a planetary configuration can produce a dipole field consistent with Mariner 10 results. In the next full proposal cycle we will: (1) develop numerical and analytical and models of thin shell dynamos to address the possible nature of Mercury s present-day magnetic field and the demise of Mars magnetic field; (2) study the effect of degree-1 mantle convection on a core dynamo as relevant to the early magnetic field of Mars; (3) develop models of how the deep mantles of terrestrial planets are perturbed by large impacts and address the consequences for mantle evolution; (4) study the structure, compensation, state of stress, and viscous relaxation of lunar basins, and address implications for the Moon s state of stress and thermal history by modeling and gravity/topography analysis; and (5) use a three-dimensional viscous relaxation model for a planet with generalized vertical viscosity distribution to study the degree-two components of the Moon's topography and gravity fields to constrain the primordial stress state and spatial heterogeneity of the crust and mantle.

  4. Introducing PLIA: Planetary Laboratory for Image Analysis

    Science.gov (United States)

    Peralta, J.; Hueso, R.; Barrado, N.; Sánchez-Lavega, A.

    2005-08-01

    We present a graphical software tool developed under IDL software to navigate, process and analyze planetary images. The software has a complete Graphical User Interface and is cross-platform. It can also run under the IDL Virtual Machine without the need to own an IDL license. The set of tools included allow image navigation (orientation, centring and automatic limb determination), dynamical and photometric atmospheric measurements (winds and cloud albedos), cylindrical and polar projections, as well as image treatment under several procedures. Being written in IDL, it is modular and easy to modify and grow for adding new capabilities. We show several examples of the software capabilities with Galileo-Venus observations: Image navigation, photometrical corrections, wind profiles obtained by cloud tracking, cylindrical projections and cloud photometric measurements. Acknowledgements: This work has been funded by Spanish MCYT PNAYA2003-03216, fondos FEDER and Grupos UPV 15946/2004. R. Hueso acknowledges a post-doc fellowship from Gobierno Vasco.

  5. Probing Planetary Formation and Evolution Through Occultations

    Science.gov (United States)

    Rodriguez, Joseph E.; KELT Team

    2016-01-01

    The circumstellar environments of young stellar objects (YSOs) involve complex dynamical interactions between dust and gas that directly influence the formation of planets. However, our understanding of the evolution from the material in the circumstellar disk to the thousands of planetary systems discovered to date, is limited. One means to better constrain the size, mass, and composition of this planet-forming material is to observe a YSO being eclipsed by its circumstellar disk. Through this dissertation project, we are discovering and characterizing both disk eclipsing systems and exoplanets using the Kilodegree Extremely Little Telescope (KELT) project. KELT is a photometric survey for transiting planets orbiting bright stars (8 TYC 2505-672-1, the latter now representing the longest-period eclipsing object known (period ~ 69 years). I will describe our results for planet atmosphere characterization and for protoplanetary disk structure and composition, and discuss how to search for these kinds of systems in future surveys such as LSST.

  6. Stationary planetary wave propagation in Northern Hemisphere winter – climatological analysis of the refractive index

    Directory of Open Access Journals (Sweden)

    Q. Li

    2007-01-01

    Full Text Available The probability density on a height-meridional plane of negative refractive index squared f(nk2<0 is introduced as a new analysis tool to investigate the climatology of the propagation conditions of stationary planetary waves based on NCEP/NCAR reanalysis data for 44 Northern Hemisphere boreal winters (1958–2002. This analysis addresses the control of the atmospheric state on planetary wave propagation. It is found that not only the variability of atmospheric stability with altitudes, but also the variability with latitudes has significant influence on planetary wave propagation. Eliassen-Palm flux and divergence are also analyzed to investigate the eddy activities and forcing on zonal mean flow. Only the ultra-long planetary waves with zonal wave number 1, 2 and 3 are investigated. In Northern Hemisphere winter the atmosphere shows a large possibility for stationary planetary waves to propagate from the troposphere to the stratosphere. On the other hand, waves induce eddy momentum flux in the subtropical troposphere and eddy heat flux in the subpolar stratosphere. Waves also exert eddy momentum forcing on the mean flow in the troposphere and stratosphere at middle and high latitudes. A similar analysis is also performed for stratospheric strong and weak polar vortex regimes, respectively. Anomalies of stratospheric circulation affect planetary wave propagation and waves also play an important role in constructing and maintaining of interannual variations of stratospheric circulation.

  7. of Planetary Nebulae III. NGC 6781

    Directory of Open Access Journals (Sweden)

    Hugo E. Schwarz

    2006-01-01

    Full Text Available Continuing our series of papers on the three-dimensional (3D structures and accurate distances to Planetary Nebulae (PNe, we present our study of the planetary nebula NGC6781. For this object we construct a 3D photoionization model and, using the constraints provided by observational data from the literature we determine the detailed 3D structure of the nebula, the physical parameters of the ionizing source and the first precise distance. The procedure consists in simultaneously fitting all the observed emission line morphologies, integrated intensities and the two-dimensional (2D density map from the [SII] (sulfur II line ratios to the parameters generated by the model, and in an iterative way obtain the best fit for the central star parameters and the distance to NGC6781, obtaining values of 950±143 pc (parsec – astronomic distance unit and 385 LΘ (solar luminosity for the distance and luminosity of the central star respectively. Using theoretical evolutionary tracks of intermediate and low mass stars, we derive the mass of the central star of NGC6781 and its progenitor to be 0.60±0.03MΘ (solar mass and 1.5±0.5MΘ respectively.

  8. Strontium iodide gamma ray spectrometers for planetary science (Conference Presentation)

    Science.gov (United States)

    Prettyman, Thomas H.; Rowe, Emmanuel; Butler, Jarrhett; Groza, Michael; Burger, Arnold; Yamashita, Naoyuki; Lambert, James L.; Stassun, Keivan G.; Beck, Patrick R.; Cherepy, Nerine J.; Payne, Stephen A.; Castillo-Rogez, Julie C.; Feldman, Sabrina M.; Raymond, Carol A.

    2016-09-01

    Gamma rays produced passively by cosmic ray interactions and by the decay of radioelements convey information about the elemental makeup of planetary surfaces and atmospheres. Orbital missions mapped the composition of the Moon, Mars, Mercury, Vesta, and now Ceres. Active neutron interrogation will enable and/or enhance in situ measurements (rovers, landers, and sondes). Elemental measurements support planetary science objectives as well as resource utilization and planetary defense initiatives. Strontium iodide, an ultra-bright scintillator with low nonproportionality, offers significantly better energy resolution than most previously flown scintillators, enabling improved accuracy for identification and quantification of key elements. Lanthanum bromide achieves similar resolution; however, radiolanthanum emissions obscure planetary gamma rays from radioelements K, Th, and U. The response of silicon-based optical sensors optimally overlaps the emission spectrum of strontium iodide, enabling the development of compact, low-power sensors required for space applications, including burgeoning microsatellite programs. While crystals of the size needed for planetary measurements (>100 cm3) are on the way, pulse-shape corrections to account for variations in absorption/re-emission of light are needed to achieve maximum resolution. Additional challenges for implementation of large-volume detectors include optimization of light collection using silicon-based sensors and assessment of radiation damage effects and energetic-particle induced backgrounds. Using laboratory experiments, archived planetary data, and modeling, we evaluate the performance of strontium iodide for future missions to small bodies (asteroids and comets) and surfaces of the Moon and Venus. We report progress on instrument design and preliminary assessment of radiation damage effects in comparison to technology with flight heritage.

  9. Interstellar Transfer of Planetary Microbiota

    Science.gov (United States)

    Wallis, Max K.; Wickramasinghe, N. C.

    Panspermia theories require the transport of micro-organisms in a viable form from one astronomical location to another. The evidence of material ejection from planetary surfaces, of dynamical orbit evolution and of potential survival on landing is setting a firm basis for interplanetary panspermia. Pathways for interstellar panspermia are less clear. We compare the direct route, whereby life-bearing planetary ejecta exit the solar system and risk radiation hazards en route to nearby stellar systems, and an indirect route whereby ejecta hitch a ride within the shielded environment of comets of the Edgeworth- Kuiper Belt that are subsequently expelled from the solar system. We identify solutions to the delivery problem. Delivery to fully-fledged planetary systems of either the direct ejecta or the ejecta borne by comets depends on dynamical capture and is of very low efficiency. However, delivery into a proto-planetary disc of an early solar-type nebula and into pre-stellar molecular clouds is effective, because the solid grains efficiently sputter the incoming material in hypervelocity collisions. The total mass of terrestrial fertile material delivered to nearby pre-stellar systems as the solar system moves through the galaxy is from kilogrammes up to a tonne. Subject to further study of bio-viability under irradiation and fragmenting collisions, a few kg of original grains and sputtered fragments could be sufficient to seed the planetary system with a wide range of solar system micro-organisms.

  10. The Planetary Archive

    Science.gov (United States)

    Penteado, Paulo F.; Trilling, David; Szalay, Alexander; Budavári, Tamás; Fuentes, César

    2014-11-01

    We are building the first system that will allow efficient data mining in the astronomical archives for observations of Solar System Bodies. While the Virtual Observatory has enabled data-intensive research making use of large collections of observations across multiple archives, Planetary Science has largely been denied this opportunity: most astronomical data services are built based on sky positions, and moving objects are often filtered out.To identify serendipitous observations of Solar System objects, we ingest the archive metadata. The coverage of each image in an archive is a volume in a 3D space (RA,Dec,time), which we can represent efficiently through a hierarchical triangular mesh (HTM) for the spatial dimensions, plus a contiguous time interval. In this space, an asteroid occupies a curve, which we determine integrating its orbit into the past. Thus when an asteroid trajectory intercepts the volume of an archived image, we have a possible observation of that body. Our pipeline then looks in the archive's catalog for a source with the corresponding coordinates, to retrieve its photometry. All these matches are stored into a database, which can be queried by object identifier.This database consists of archived observations of known Solar System objects. This means that it grows not only from the ingestion of new images, but also from the growth in the number of known objects. As new bodies are discovered, our pipeline can find archived observations where they could have been recorded, providing colors for these newly-found objects. This growth becomes more relevant with the new generation of wide-field surveys, particularly LSST.We also present one use case of our prototype archive: after ingesting the metadata for SDSS, 2MASS and GALEX, we were able to identify serendipitous observations of Solar System bodies in these 3 archives. Cross-matching these occurrences provided us with colors from the UV to the IR, a much wider spectral range than that

  11. Planetary Image Geometry Library

    Science.gov (United States)

    Deen, Robert C.; Pariser, Oleg

    2010-01-01

    The Planetary Image Geometry (PIG) library is a multi-mission library used for projecting images (EDRs, or Experiment Data Records) and managing their geometry for in-situ missions. A collection of models describes cameras and their articulation, allowing application programs such as mosaickers, terrain generators, and pointing correction tools to be written in a multi-mission manner, without any knowledge of parameters specific to the supported missions. Camera model objects allow transformation of image coordinates to and from view vectors in XYZ space. Pointing models, specific to each mission, describe how to orient the camera models based on telemetry or other information. Surface models describe the surface in general terms. Coordinate system objects manage the various coordinate systems involved in most missions. File objects manage access to metadata (labels, including telemetry information) in the input EDRs and RDRs (Reduced Data Records). Label models manage metadata information in output files. Site objects keep track of different locations where the spacecraft might be at a given time. Radiometry models allow correction of radiometry for an image. Mission objects contain basic mission parameters. Pointing adjustment ("nav") files allow pointing to be corrected. The object-oriented structure (C++) makes it easy to subclass just the pieces of the library that are truly mission-specific. Typically, this involves just the pointing model and coordinate systems, and parts of the file model. Once the library was developed (initially for Mars Polar Lander, MPL), adding new missions ranged from two days to a few months, resulting in significant cost savings as compared to rewriting all the application programs for each mission. Currently supported missions include Mars Pathfinder (MPF), MPL, Mars Exploration Rover (MER), Phoenix, and Mars Science Lab (MSL). Applications based on this library create the majority of operational image RDRs for those missions. A

  12. Spectral reflectance and atmospheric energetics in cirrus-like clouds. Part II: Applications of a Fourier-Riccati approach to radiative transfer

    Energy Technology Data Exchange (ETDEWEB)

    Tsay, S.C.; King, M.D. [NASA/Goddard Space Flight Center, Greenbelt, MD (United States); Gabriel, P.M.; Stephens, G.L. [Colorado State Univ., Fort Collins, CO (United States)

    1996-12-01

    One of the major sources of uncertainty in climate studies is the detection of cirrus clouds and characterization of their radiative properties. Combinations of water vapor absorption channels (e.g., 1.38 {mu}m), ice-water absorption channels (e.g., 1.64 {mu}m), and atmospheric window channels (e.g., 11 {mu}m) in the imager, together with a lidar profiler on future EOS platforms, will contribute to enhancing present understanding of cirrus clouds. The aforementioned spectral channels are used in this study to explore the effects exerted by uncertainties in cloud microphysical properties (e.g., particle size distribution) and cloud morphology on the apparent radiative properties, such as spectral reflectance and heating and cooling rate profiles. As in Part I of the previous study, which establishes the foundations of the Fourier-Riccati method of radiative transfer in inhomogeneous media, cloud extinction and scattering functions are characterized by simple spatial variations with measured and hypothesized microphysics to facilitate the understanding of their radiative properties. Results of this study suggest that (i) while microphysical variations in the scattering and extinction functions of clouds affect the magnitudes of their spectral reflectances, cloud morphology significantly alters the shape of their angular distribution; (ii) spectral reflectances viewed near nadir are least affected by cloud variability; and (iii) cloud morphology can lead to spectral heating and cooling rate profiles that differ substantially from their plane-parallel averaged equivalents. Since there are no horizontal thermal gradients in plane-parallel clouds, it may be difficult to correct for this deficiency. 32 refs., 11 figs., 1 tab.

  13. Planetary cubesats - mission architectures

    Science.gov (United States)

    Bousquet, Pierre W.; Ulamec, Stephan; Jaumann, Ralf; Vane, Gregg; Baker, John; Clark, Pamela; Komarek, Tomas; Lebreton, Jean-Pierre; Yano, Hajime

    2016-07-01

    Miniaturisation of technologies over the last decade has made cubesats a valid solution for deep space missions. For example, a spectacular set 13 cubesats will be delivered in 2018 to a high lunar orbit within the frame of SLS' first flight, referred to as Exploration Mission-1 (EM-1). Each of them will perform autonomously valuable scientific or technological investigations. Other situations are encountered, such as the auxiliary landers / rovers and autonomous camera that will be carried in 2018 to asteroid 1993 JU3 by JAXA's Hayabusas 2 probe, and will provide complementary scientific return to their mothership. In this case, cubesats depend on a larger spacecraft for deployment and other resources, such as telecommunication relay or propulsion. For both situations, we will describe in this paper how cubesats can be used as remote observatories (such as NEO detection missions), as technology demonstrators, and how they can perform or contribute to all steps in the Deep Space exploration sequence: Measurements during Deep Space cruise, Body Fly-bies, Body Orbiters, Atmospheric probes (Jupiter probe, Venus atmospheric probes, ..), Static Landers, Mobile landers (such as balloons, wheeled rovers, small body rovers, drones, penetrators, floating devices, …), Sample Return. We will elaborate on mission architectures for the most promising concepts where cubesat size devices offer an advantage in terms of affordability, feasibility, and increase of scientific return.

  14. Discovery of New Faint Northern Galactic Planetary Nebulae

    CERN Document Server

    Acker, Agnes; Outters, Nicolas; Miszalski, Brent; Sabin, Laurence; Le Du, Pascal; Alves, Filipe

    2012-01-01

    We present the discovery of 6 nebular objects made by amateur astronomers. Four of these discoveries are clearly planetary nebulae (PNe), one is a possible PN, and another is a likely H II region. The bipolar nebula Ou4 presents the largest angular extent ever found : over one degree on the sky! We consider various scenarios that could explain such a nebula. Ou4 could be one of the nearest PNe known, though its possible PN nature will need confirmation.

  15. Observations of Exoplanet Atmospheres

    CERN Document Server

    Crossfield, Ian J M

    2015-01-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  16. Variational Principle for Planetary Interiors

    CERN Document Server

    Zeng, Li

    2016-01-01

    In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. Variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying this principle to planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From it, a universal mass-radius relation, an estimate of error propagation from equation of state to mass-radius relation, and a form of virial theorem applicable to planetary interiors are derived.

  17. Planetary systems in star clusters

    CERN Document Server

    Kouwenhoven, M B N; Cai, Maxwell Xu; Spurzem, Rainer

    2016-01-01

    Thousands of confirmed and candidate exoplanets have been identified in recent years. Consequently, theoretical research on the formation and dynamical evolution of planetary systems has seen a boost, and the processes of planet-planet scattering, secular evolution, and interaction between planets and gas/debris disks have been well-studied. Almost all of this work has focused on the formation and evolution of isolated planetary systems, and neglect the effect of external influences, such as the gravitational interaction with neighbouring stars. Most stars, however, form in clustered environments that either quickly disperse, or evolve into open clusters. Under these conditions, young planetary systems experience frequent close encounters with other stars, at least during the first 1-10 Myr, which affects planets orbiting at any period range, as well as their debris structures.

  18. Variational Principle for Planetary Interiors

    Science.gov (United States)

    Zeng, Li; Jacobsen, Stein B.

    2016-09-01

    In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. The variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory, which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying the variational principle to the planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From this principle, a universal mass-radius relation, an estimate of the error propagation from the equation of state to the mass-radius relation, and a form of the virial theorem applicable to planetary interiors are derived.

  19. Rigidized Deployable Lifting Brake for Atmospheric Entry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerobraking to reduce velocity for planetary capture and landing has long been assumed for use on Mars missions because Mars has an atmosphere, and the use of...

  20. From Planetary Mapping to Map Production: Planetary Cartography as integral discipline in Planetary Sciences

    Science.gov (United States)

    Nass, Andrea; van Gasselt, Stephan; Hargitai, Hendrik; Hare, Trent; Manaud, Nicolas; Karachevtseva, Irina; Kersten, Elke; Roatsch, Thomas; Wählisch, Marita; Kereszturi, Akos

    2016-04-01

    Cartography is one of the most important communication channels between users of spatial information and laymen as well as the open public alike. This applies to all known real-world objects located either here on Earth or on any other object in our Solar System. In planetary sciences, however, the main use of cartography resides in a concept called planetary mapping with all its various attached meanings: it can be (1) systematic spacecraft observation from orbit, i.e. the retrieval of physical information, (2) the interpretation of discrete planetary surface units and their abstraction, or it can be (3) planetary cartography sensu strictu, i.e., the technical and artistic creation of map products. As the concept of planetary mapping covers a wide range of different information and knowledge levels, aims associated with the concept of mapping consequently range from a technical and engineering focus to a scientific distillation process. Among others, scientific centers focusing on planetary cartography are the United State Geological Survey (USGS, Flagstaff), the Moscow State University of Geodesy and Cartography (MIIGAiK, Moscow), Eötvös Loránd University (ELTE, Hungary), and the German Aerospace Center (DLR, Berlin). The International Astronomical Union (IAU), the Commission Planetary Cartography within International Cartographic Association (ICA), the Open Geospatial Consortium (OGC), the WG IV/8 Planetary Mapping and Spatial Databases within International Society for Photogrammetry and Remote Sensing (ISPRS) and a range of other institutions contribute on definition frameworks in planetary cartography. Classical cartography is nowadays often (mis-)understood as a tool mainly rather than a scientific discipline and an art of communication. Consequently, concepts of information systems, mapping tools and cartographic frameworks are used interchangeably, and cartographic workflows and visualization of spatial information in thematic maps have often been

  1. FOREWORD: International Conference on Planetary Boundary Layer and Climate Change

    Science.gov (United States)

    Djolov, G.; Esau, I.

    2010-05-01

    structural uncertainties is hard to reduce and this could be one of the reasons determining slow progress in narrowing the climate model uncertainty range over the last 30 years (Knutti and Hagerl, Nature Geoscience, 2008). One of the most prominent structural uncertainties in the ongoing transient climate change is related to poor understanding and hence incorrect modelling of the turbulent physics and dynamics processes in the planetary boundary layer. Nevertheless, the climate models continue to rely on physically incorrect boundary layer parameterizations (Cuxart et al., BLM, 2006), whose erroneous dynamical response in the climate models may lead to significant abnormalities in simulated climate. At present, international efforts in theoretical understanding of the turbulent mixing have resulted in significant progress in turbulence simulation, measurements and parameterizations. However, this understanding has not yet found its way to the climate research community. Vice versa, climate research is not usually addressed by the boundary layer research community. The gap needs to be closed in order to crucially complete the scientific basis of climate change studies. The focus of the proposed forum could be formulated as follows: The planetary boundary layer determines several key parameters controlling the Earth's climate system but being a dynamic sub-system, just a layer of turbulent mixing in the atmosphere/ocean, it is also controlled by the climate system and its changes. Such a dynamic relationship causes a planetary boundary layer feedback (PBL-feedback) which could be defined as the response of the surface air temperature on changes in the vertical turbulent mixing. The forum participants have discussed both climatological and fluid dynamic aspects of this response, in order to quantify their role in the Earth's transient heat uptake and its representation in climate models. The choice of the forum location and dates are motivated by the role of tropical oceans

  2. Kinematic study of planetary nebulae in NGC 6822

    CERN Document Server

    Flores-Durán, S N; Hernández-Martínez, L; García-Rojas, J; Ruiz, M T

    2014-01-01

    By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\\'omico Nacional, M\\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s$^{-1}$. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The...

  3. Proceedings of the 38th Lunar and Planetary Science Conference

    Science.gov (United States)

    2007-01-01

    The sessions in the conference include: Titan, Mars Volcanism, Mars Polar Layered Deposits, Early Solar System Isotopes, SPECIAL SESSION: Mars Reconnaissance Orbiter: New Ways of Studying the Red Planet, Achondrites: Exploring Oxygen Isotopes and Parent-Body Processes, Solar System Formation and Evolution, SPECIAL SESSION: SMART-1, . Impact Cratering: Observations and Experiments, SPECIAL SESSION: Volcanism and Tectonism on Saturnian Satellites, Solar Nebula Composition, Mars Fluvial Geomorphology, Asteroid Observations: Spectra, Mostly, Mars Sediments and Geochemistry: View from the Surface, Mars Tectonics and Crustal Dichotomy, Stardust: Wild-2 Revealed, Impact Cratering from Observations and Interpretations, Mars Sediments and Geochemistry: The Map View, Chondrules and Their Formation, Enceladus, Asteroids and Deep Impact: Structure, Dynamics, and Experiments, Mars Surface Process and Evolution, Martian Meteorites: Nakhlites, Experiments, and the Great Shergottite Age Debate, Stardust: Mainly Mineralogy, Astrobiology, Wind-Surface Interactions on Mars and Earth, Icy Satellite Surfaces, Venus, Lunar Remote Sensing, Space Weathering, and Impact Effects, Interplanetary Dust/Genesis, Mars Cratering: Counts and Catastrophes?, Chondrites: Secondary Processes, Mars Sediments and Geochemistry: Atmosphere, Soils, Brines, and Minerals, Lunar Interior and Differentiation, Mars Magnetics and Atmosphere: Core to Ionosphere, Metal-rich Chondrites, Organics in Chondrites, Lunar Impacts and Meteorites, Presolar/Solar Grains, Topics for Print Only papers are: Outer Planets/Satellites, Early Solar System, Interplanetary Dust, Comets and Kuiper Belt Objects, Asteroids and Meteoroids, Chondrites, Achondrites, Meteorite Related, Mars Reconnaissance Orbiter, Mars, Astrobiology, Planetary Differentiation, Impacts, Mercury, Lunar Samples and Modeling, Venus, Missions and Instruments, Global Warming, Education and Public Outreach, Poster sessions are: Asteroids/Kuiper Belt Objects

  4. Planetary wave variability of Sq currents

    Science.gov (United States)

    Elhawary, R.; Forbes, J. M.

    2016-11-01

    The E region wind dynamo is a key linkage in atmosphere-ionosphere coupling, but relatively little is known about variability of the corresponding E region currents in terms of connections with atmosphere dynamics. In this paper we analyze ground magnetic variations ΔB during 2009 at two midlatitude stations to reveal planetary wave (PW) periodicities near those of well-known atmospheric normal modes, i.e., 5, 10, and 16 days. In the neutral atmosphere these waves are westward propagating with zonal wave number s = 1. The two stations are at the same magnetic latitude and are nearly conjugate in longitude, which leads to following new insights: First, the amplitude and phase variations between the two stations do not conform to simple westward propagating waves with zonal wave number s = 1, implying that the underlying physics is more complex, in part due to modulation by the predominantly s = 1 longitude-dependent magnetic field. There is also compelling evidence that much ΔB variability near PW periods arises through the product of solar-controlled conductivity and PW-related electric field in the expression for electric current, mainly arising from solar radiation periodicities longer than the solar rotation period. For instance, interactions between solar periodicities in conductivity near 53d and 83d and PW periodicities in total electric field yield secondary peaks in the ΔB spectrum that contribute to its variability at periods less than 20d. In fact, most of the observed ΔB variability arises from these two latter sources, rather than directly from the original driving PW oscillations.

  5. The planetary nebula Abell 48 and its [WN4] nucleus

    CERN Document Server

    Frew, David J; Parker, Q A; Stupar, M; Wachter, S; DePew, K; Danehkar, A; Fitzgerald, M F

    2013-01-01

    We have conducted a detailed multi-wavelength study of the peculiar planetary nebula Abell 48 and its central star. We present evidence for a new classification of the nucleus as a helium-rich, hydrogen-deficient star of type [WN4], one of only two currently known examples of its type. The evidence for either a massive WN or a low-mass [WN] interpretation is critically examined, and we firmly conclude that Abell 48 is a planetary nebula around an evolved low-mass star, rather than a Population I ejecta nebula. Importantly, the surrounding nebula has a morphology typical of planetary nebulae, and is not enriched in nitrogen, and thus not the 'peeled atmosphere' of a massive star. We estimate a distance of 1.6 kpc and a reddening, E(B-V) = 1.90 mag, the latter value clearly showing the nebula lies on the near side of the Galactic bar, and therefore cannot be a massive WN star. The planetary nebula has an ionized mass (0.3 M_sun) and electron density (740 cm^-3) typical of somewhat evolved objects. The observed ...

  6. Ohmic Dissipation in the Atmospheres of Hot Jupiters

    CERN Document Server

    Perna, Rosalba; Rauscher, Emily

    2010-01-01

    Hot Jupiter atmospheres exhibit fast, weakly-ionized winds. The interaction of these winds with the planetary magnetic field generates drag on the winds and leads to ohmic dissipation of the induced electric currents. We study the magnitude of ohmic dissipation in representative, three-dimensional atmospheric circulation models of the hot Jupiter HD 209458b. We find that ohmic dissipation can reach or exceed 1% of the stellar insolation power in the deepest atmospheric layers, in models with and without dragged winds. Such power, dissipated in the deep atmosphere, appears sufficient to slow down planetary contraction and explain the typically inflated radii of hot Jupiters. This atmospheric scenario does not require a top insulating layer or radial currents that penetrate deep in the planetary interior. Circulation in the deepest atmospheric layers may actually be driven by spatially non-uniform ohmic dissipation. A consistent treatment of magnetic drag and ohmic dissipation is required to further elucidate t...

  7. Revised Diagnostic Diagrams for Planetary Nebulae

    CERN Document Server

    Riesgo, H

    2006-01-01

    Diagnostic diagrams of electron density - excitation for a sample of 613 planetary nebulae are presented. The present extensive sample allows the definition of new statistical limits for the distribution of planetary nebulae in the log [Ha/[SII

  8. The abundances of neon, sulfur, and argon in planetary nebulae

    Science.gov (United States)

    Beck, S. C.; Lacy, J. H.; Townes, C. H.; Aller, L. H.; Geballe, T. R.; Baas, F.

    1981-01-01

    New infrared observations of Ne II, Ar III, and S IV are used in optical observations of other ionization states of the considered elements to evaluate the abundances of neon, argon, and sulfur in 18 planetary nebulae. Attention is also given to one or more of the infrared lines in 18 other nebulae. It is pointed out that S IV was detected in approximately 90% of the observed objects, while Ar III was found in about 80%, and Ne II in roughly one-third. It is noted that optical observations typically include only a limited region of the nebula, while the infrared measurements frequently involve integration over the entire nebular image.

  9. International Infrastructure for Planetary Sciences: Universal Planetary Database Development Project 'the International Planetary Data Alliance'

    Science.gov (United States)

    Kasaba, Yasumasa; Crichton, D.; Capria, M. T.; Beebe, R.; Zender, J.

    2009-09-01

    The International Planetary Data Alliance (IPDA), formed under COSPAR in 2008, is a joint international effort to enable global access and exchange of high quality planetary science data, and to establish archive standards that make it easier to share data across international boundaries. In June - July 2009, we held the 4th Steering Committee meeting. Thanks to the many players from several agencies and institutions in the world, we got fruitful results in 6 projects: (1) Inter-operable Planetary Data Access Protocol (PDAP) implementations [led by J. Salgado@ESA], (2) Small bodies interoperability [led by I. Shinohara@JAXA & N. Hirata@U. Aizu], (3) PDAP assessment [led by Y. Yamamoto@JAXA], (4) Architecture and standards definition [led by D. Crichton@NASA], (5) Information model and data dictionary [led by S. Hughes@NASA], and (6) Venus Express Interoperability [led by N. Chanover@NMSU]. The projects demonstrated the feasibility of sharing data and emphasized the importance of developing common data standards to ensure world-wide access to international planetary archives. The Venus Express Interoperability project leveraged standards and technology efforts from both the Planetary Data System (PDS) and IPDA in order to deliver a new capability for data sharing between NASA/PDS and ESA/PSA. This project demonstrated a model and framework for linking compliant planetary archive systems for future international missions. The next step for IPDA, during the 2009-2010 period, will be to work with NASA/PDS to review and participate in an upgrade of its standards to improve both the consistency of the standards to build compliant international archives as well as improve long-term usability of the science data products. This paper presents the achievements and plans, which will be summarized in the paper which will appear in 'Space Research Today' in December 2009.

  10. Planetary Environments: Scientific Issues and Perspectives

    Directory of Open Access Journals (Sweden)

    Encrenaz Th.

    2014-02-01

    Full Text Available What are the planetary environments where conditions are best suited for habitability? A first constraint is provided by the presence of liquid water. This condition allows us to define two kinds of media: (1 the atmospheres of solid (exoplanets with a temperature typically ranging between 0°C and 100°C, and (2 the interiors of icy bodies (outer satellites or possibly exosatellites where the pressure and temperature would fit the liquid phase region of the water phase diagram. In the case of Mars, significant progress has been achieved about our understanding of the history of liquid water in the past, thanks to the findings of recent space missions. The study of the outer satellites is also benefiting from the on-going operation of the Cassini mission. In the case of exopl nets, new discoveries are continuously reported, especially with the Kepler mission, in operation since 2009. With the emergence of transit spectroscopy, a new phase of exoplanets’ exploration has started, their characterization, opening the new field of exoplanetology. In the future, new perspectives appear regarding the exploration of Mars, the giant planets and exoplanets, with the ultimate goal of characterizing the atmospheres of temperate exoplanets.

  11. Small Spacecraft for Planetary Science

    Science.gov (United States)

    Baker, John; Castillo-Rogez, Julie; Bousquet, Pierre-W.; Vane, Gregg; Komarek, Tomas; Klesh, Andrew

    2016-07-01

    As planetary science continues to explore new and remote regions of the Solar system with comprehensive and more sophisticated payloads, small spacecraft offer the possibility for focused and more affordable science investigations. These small spacecraft or micro spacecraft (electronics, advanced manufacturing for lightweight structures, and innovative propulsion are making it possible to fly much more capable micro spacecraft for planetary exploration. While micro spacecraft, such as CubeSats, offer significant cost reductions with added capability from advancing technologies, the technical challenges for deep space missions are very different than for missions conducted in low Earth orbit. Micro spacecraft must be able to sustain a broad range of planetary environments (i.e., radiations, temperatures, limited power generation) and offer long-range telecommunication performance on a par with science needs. Other capabilities needed for planetary missions, such as fine attitude control and determination, capable computer and data handling, and navigation are being met by technologies currently under development to be flown on CubeSats within the next five years. This paper will discuss how micro spacecraft offer an attractive alternative to accomplish specific science and technology goals and what relevant technologies are needed for these these types of spacecraft. Acknowledgements: Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to NASA. Government sponsorship acknowledged.

  12. Virtual reality and planetary exploration

    Science.gov (United States)

    McGreevy, Michael W.

    Exploring planetary environments is central to NASA's missions and goals. A new computing technology called Virtual Reality has much to offer in support of planetary exploration. This technology augments and extends human presence within computer-generated and remote spatial environments. Historically, NASA has been a leader in many of the fundamental concepts and technologies that comprise Virtual Reality. Indeed, Ames Research Center has a central role in the development of this rapidly emerging approach to using computers. This ground breaking work has inspired researchers in academia, industry, and the military. Further, NASA's leadership in this technology has spun off new businesses, has caught the attention of the international business community, and has generated several years of positive international media coverage. In the future, Virtual Reality technology will enable greatly improved human-machine interactions for more productive planetary surface exploration. Perhaps more importantly, Virtual Reality technology will democratize the experience of planetary exploration and thereby broaden understanding of, and support for, this historic enterprise.

  13. Dynamical Simulations of the Planetary System HD69830

    CERN Document Server

    Payne, Matthew J; Wyatt, Mark C; Booth, Mark

    2008-01-01

    HD 69830 exhibits radial velocity variations attributed to three planets as well as infrared emission attributed to a warm debris disk. Previous studies have developed models for the planet migration and mass growth (Alibert et al. 2006) and the replenishment of warm grains (Wyatt et al. 2007). We perform n-body integrations in order to explore the implications of these models for: 1) the excitation of planetary eccentricity, 2) the accretion and clearing of a putative planetesimal disk, 3) the distribution of planetesimal orbits following migration, and 4) the implications for the origin of the IR emission. We find that: i) It is not possible to explain the observed planetary eccentricities (e~0.1) purely as the result of planetary perturbations during migration unless the planetary system is nearly face-on. ii) The rate of accretion of planetesimals onto planets in our n-body simulations is significantly different to that assumed in the semi-analytic models, suggesting that one cannot successfully treat pla...

  14. PLANETARY EMBRYO BOW SHOCKS AS A MECHANISM FOR CHONDRULE FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Christopher R.; Boley, Aaron C. [Department of Physics and Astronomy University of British Columbia Vancouver, BC V6T 1Z1 (Canada); Morris, Melissa A. [Physics Department State University of New York at Cortland Cortland, NY 13045 (United States)

    2016-02-20

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s{sup −1} are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  15. Planetary Embryo Bow Shocks as a Mechanism for Chondrule Formation

    Science.gov (United States)

    Mann, Christopher R.; Boley, Aaron C.; Morris, Melissa A.

    2016-02-01

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s-1 are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  16. Forest atmosphere carbon transfer and storage (FACTS-II) the aspen Free-air CO2 and O3 Enrichment (FACE) project: an overview.

    Science.gov (United States)

    R.E. Dickson; K.F. Lewin; J.G. Isebrands; M.D. Coleman; W.E. Heilman; D.E. Riemenschneider; J. Sober; G.E. Host; D.R. Zak; G.R. Hendrey; K.S. Pregitzer; D.F. Karnosky

    2000-01-01

    This publication briefly reviews the impact of increasing atmospheric carbon dioxide and tropospheric ozone on global climate change, and the response of forest trees to these atmospheric pollutants and their interactions; points out the need for large-scale field experiments to evaluate the response of plants to these environmental stresses; and describes the...

  17. Simulating super earth atmospheres in the laboratory

    Science.gov (United States)

    Claudi, R.; Erculiani, M. S.; Galletta, G.; Billi, D.; Pace, E.; Schierano, D.; Giro, E.; D'Alessandro, M.

    2016-01-01

    Several space missions, such as JWST, TESS and the very recently proposed ARIEL, or ground-based experiments, as SPHERE and GPI, have been proposed to measure the atmospheric transmission, reflection and emission spectra of extrasolar planets. The planet atmosphere characteristics and possible biosignatures will be inferred by studying planetary spectra in order to identify the emission/absorption lines/bands from atmospheric molecules such as water (H2O), carbon monoxide (CO), methane (CH4), ammonia (NH3), etc. In particular, it is important to know in detail the optical characteristics of gases in the typical physical conditions of the planetary atmospheres and how these characteristics could be affected by radiation driven photochemical and biochemical reaction. The main aim of the project `Atmosphere in a Test Tube' is to provide insights on exoplanet atmosphere modification due to biological intervention. This can be achieved simulating planetary atmosphere at different pressure and temperature conditions under the effects of radiation sources, used as proxies of different bands of the stellar emission. We are tackling the characterization of extrasolar planet atmospheres by mean of innovative laboratory experiments described in this paper. The experiments are intended to reproduce the conditions on warm earths and super earths hosted by low-mass M dwarfs primaries with the aim to understand if a cyanobacteria population hosted on a Earth-like planet orbiting an M0 star is able to maintain its photosynthetic activity and produce traceable signatures.

  18. Planetary exploration and science recent results and advances

    CERN Document Server

    Jin, Shuanggen; Ip, Wing-Huen

    2014-01-01

    This contributed monograph is the first work to present the latest results and findings on the new topic and hot field of planetary exploration and sciences, e.g., lunar surface iron content and mare orientale basalts, Earth's gravity field, Martian radar exploration, crater recognition, ionosphere and astrobiology, Comet ionosphere, exoplanetary atmospheres and planet formation in binaries. By providing detailed theory and examples, this book helps readers to quickly familiarize themselves with the field. In addition, it offers a special section on next-generation planetary exploration, which opens a new landscape for future exploration plans and missions. Prof. Shuanggen Jin works at the Shanghai Astronomical Observatory, Chinese Academy of Sciences, China. Dr. Nader Haghighipour works at the University of Hawaii-Manoa, USA. Prof. Wing-Huen Ip works at the National Central University, Taiwan.

  19. Efficiency of Planetesimal Ablation in Giant Planetary Envelopes

    CERN Document Server

    Pinhas, Arazi; Clarke, Cathie

    2016-01-01

    Observations of exoplanetary spectra are leading to unprecedented constraints on their atmospheric elemental abundances, particularly O/H, C/H, and C/O ratios. Recent studies suggest that elemental ratios could provide important constraints on formation and migration mechanisms of giant exoplanets. A fundamental assumption in such studies is that the chemical composition of the planetary envelope represents the sum-total of compositions of the accreted gas and solids during the formation history of the planet. We investigate the efficiency with which accreted planetesimals ablate in a giant planetary envelope thereby contributing to its composition rather than sinking to the core. From considerations of aerodynamic drag causing `frictional ablation' and the envelope temperature structure causing `thermal ablation', we compute mass ablations for impacting planetesimals of radii 30 m to 1 km for different compositions (ice to iron) and a wide range of velocities and impact angles, assuming spherical symmetry. I...

  20. Strong Dependence of the Inner Edge of the Habitable Zone on Planetary Rotation Rate

    CERN Document Server

    Yang, Jun; Fabrycky, Daniel C; Abbot, Dorian S

    2014-01-01

    Planetary rotation rate is a key parameter in determining atmospheric circulation and hence the spatial pattern of clouds. Since clouds can exert a dominant control on planetary radiation balance, rotation rate could be critical for determining mean planetary climate. Here we investigate this idea using a three-dimensional general circulation model with a sophisticated cloud scheme. We find that slowly rotating planets (like Venus) can maintain an Earth-like climate at nearly twice the stellar flux as rapidly rotating planets (like Earth). This suggests that many exoplanets previously believed to be too hot may actually be habitable, depending on their rotation rate. The explanation for this behavior is that slowly rotating planets have a weak Coriolis force and long daytime illumination, which promotes strong convergence and convection in the substellar region. This produces a large area of optically thick clouds, which greatly increases the planetary albedo. In contrast, on rapidly rotating planets a much n...

  1. The spatial distribution of planetary ion fluxes near Mars observed by MAVEN

    Science.gov (United States)

    Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.; Bougher, S. W.; Curry, S.; Dong, C. F.; Dong, Y.; Eparvier, F.; Fang, X.; Fortier, K.; Hara, T.; Harada, Y.; Jakosky, B. M.; Lillis, R. J.; Livi, R.; Luhmann, J. G.; Ma, Y.; Modolo, R.; Seki, K.

    2015-11-01

    We present the results of an initial effort to statistically map the fluxes of planetary ions on a closed surface around Mars. Choosing a spherical shell ~1000 km above the planet, we map both outgoing and incoming ion fluxes (with energies >25 eV) over a 4 month period. The results show net escape of planetary ions behind Mars and strong fluxes of escaping ions from the northern hemisphere with respect to the solar wind convection electric field. Planetary ions also travel toward the planet, and return fluxes are particularly strong in the southern electric field hemisphere. We obtain a lower bound estimate for planetary ion escape of ~3 × 1024 s-1, accounting for the ~10% of ions that return toward the planet and assuming that the ~70% of the surface covered so far is representative of the regions not yet visited by Mars Atmosphere and Volatile EvolutioN (MAVEN).

  2. Atmospheres of Extrasolar Giant Planets

    Science.gov (United States)

    Marley, M. S.; Fortney, J.; Seager, S.; Barman, T.

    The key to understanding an extrasolar giant planet's spectrum - and hence its detectability and evolution - lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets (EGPs) are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of EGPs and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a single stellar system leads to the study of comparative planetary architectures.

  3. Electrical discharges in planetary upper atmospheres: thermal and chemical effects

    OpenAIRE

    Parra Rojas, Francisco Carlos

    2015-01-01

    Introducción Los TLEs (Transient Luminous Events) son enormes estructuras luminosas muy breves (< 100 ms), asociadas a una fuerte actividad tormentosa, que se desarrollan entre la estratosfera (15 km) y la ionosfera (100 km) y fueron descubiertos en 1989 [1]. De la amplia variedad de tipos de TLEs, los sprites y los halos son los más comunes. Los halos son estructuras de plasma de forma achatada y color rojizo que se desarrollan entre los 75 km y 85 km de altitud como consecuencia de la...

  4. The greenhouse effect in a gray planetary atmosphere.

    Science.gov (United States)

    Wildt, R.

    1966-01-01

    Hopf analytical solution for values of ratio of gray absorption coefficients for insolating and escaping radiation /greenhouse parameter/ assumed constant at all depths, presenting temperature distribution graphs

  5. Generalized Geophysical Retrieval and Analysis Tool for Planetary Atmospheres Project

    Data.gov (United States)

    National Aeronautics and Space Administration — CPI proposes to develop an innovative, generalized retrieval algorithm and analysis tool (GRANT) that will facilitate analysis of remote sensing data from both...

  6. The Anthropocene: A Planetary Perspective

    Science.gov (United States)

    Anbar, A. D.; Hartnett, H. E.; York, A.; Selin, C.

    2016-12-01

    The Anthropocene is a new planetary epoch defined by the emergence of human activity as one of the most important driving forces on Earth, rivaling and also stressing the other systems that govern the planet's habitability. Public discussions and debates about the challenges of this epoch tend to be polarized. One extreme denies that humans have a planetary-scale impact, while the other wishes that this impact could disappear. The tension between these perspectives is often paralyzing. Effective adaptation and mitigation requires a new perspective that reframes the conversation. We propose a planetary perspective according to which this epoch is the result of a recent major innovation in the 4 ­billion ­year history of life on Earth: the emergence of an energy-intensive planetary civilization. The rate of human energy use is already within an order of magnitude of that of the rest of the biosphere, and rising rapidly, and so this innovation is second only to the evolution of photosynthesis in terms of energy capture and utilization by living systems. Such energy use has and will continue to affect Earth at planetary scale. This reality cannot be denied nor wished away. From this pragmatic perspective, the Anthropocene is not an unnatural event that can be reversed, as though humanity is separate from the Earth systems with which we are co-evolving. Rather, it is an evolutionary transition to be managed. This is the challenge of turning a carelessly altered planet into a carefully designed and managed world, maintaining a "safe operating space" for human civilization (Steffen et al., 2011). To do so, we need an integrated approach to Earth systems science that considers humans as a natural and integral component of Earth's systems. Insights drawn from the humanities and the social sciences must be integrated with the natural sciences in order to thrive in this new epoch. This type of integrated perspective is relatively uncontroversial on personal, local, and even

  7. Radiative transfer in a polluted urban planetary boundary layer

    Science.gov (United States)

    Viskanta, R.; Johnson, R. O.; Bergstrom, R. W.

    1977-01-01

    Radiative transfer in a polluted urban atmosphere is studied using a dynamic model. The diurnal nature of radiative transfer for summer conditions is simulated for an urban area 40 km in extent and the effects of various parameters arising in the problem are investigated. The results of numerical computations show that air pollution has the potential of playing a major role in the radiative regime of the urban area. Absorption of solar energy by aerosols in realistic models of urban atmosphere are of the same order of magnitude as that due to water vapor. The predicted effect of the air pollution aerosol in the city is to warm the earth-atmosphere system, and the net effect of gaseous pollutant is to warm the surface and cool the planetary boundary layer, particularly near the top.

  8. Electrifying atmospheres charging, ionisation and lightning in the solar system and beyond

    CERN Document Server

    Aplin, Karen L

    2013-01-01

    Electrical processes take place in all planetary atmospheres. There is evidence for lightning on Venus, Jupiter, Saturn, Uranus and Neptune, it is possible on Mars and Titan, and cosmic rays ionise every atmosphere, leading to charged droplets and particles. Controversy surrounds the role of atmospheric electricity in physical climate processes on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This book reviews the theory, and, where available, measurements, of planetary atmospheric electricity, taken to include ion production and ion-aerosol interactions. The conditions necessary for a global atmospheric electric circuit similar to Earth’s, and the likelihood of meeting these conditions in other planetary atmospheres, are briefly discussed. Atmospheric electrification is more important at planets receiving little solar radiation, increasing the relative significance of electrical forces. Nucleation onto atmospheric ...

  9. Variability and predictability of the space environment as related to lower atmosphere forcing

    Science.gov (United States)

    Liu, H.-L.

    2016-09-01

    The Earth's thermosphere and ionosphere (TI) are characterized by perpetual variability as integral parts of the atmosphere system, with intermittent disturbances from solar and geomagnetic forcing. This review examines how the TI variability is affected by processes originating from the lower atmosphere and implications for quantifying and forecasting the TI. This aspect of the TI variability has been increasingly appreciated in recent years from both observational and numerical studies, especially during the last extended solar minimum. This review focuses on the role of atmospheric waves, including tides, planetary waves, gravity waves, and acoustic waves, which become increasingly significant as they propagate from their source region to the upper atmosphere. Recent studies have led to better understanding of how these waves directly or indirectly affect TI wind, temperature, and compositional structures; the circulation pattern; neutral and ion species transport; and ionospheric wind dynamo. The variability of these waves on daily to interannual scales has been found to significantly impact the TI variability. Several outstanding questions and challenges have been highlighted: (i) large, seemingly stochastic, day-to-day variability of tides in the TI; (ii) control of model error in the TI region by the lower atmosphere; and (iii) the increasing importance of processes with shorter spatial and temporal scales at higher altitudes. Addressing these challenges requires model capabilities to assimilate observations of both lower and upper atmosphere and higher model resolution to capture complex interactions among processes over a broad range of scales and extended altitudes.

  10. Planetary Nebulae in Face-On Spiral Galaxies. I. Planetary Nebula Photometry and Distances

    CERN Document Server

    Herrmann, Kimberly A; Feldmeier, John J; Vinciguerra, Matt

    2008-01-01

    As the first step to determine disk mass-to-light ratios for normal spiral galaxies, we present the results of an imaging survey for planetary nebulae (PNe) in six nearby, face-on systems: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), NGC 5068, and NGC 6946. Using Blanco/Mosaic II and WIYN/OPTIC, we identify 165, 153, 241, 150, 19, and 71 PN candidates, respectively, and use the Planetary Nebula Luminosity Function (PNLF) to obtain distances. For M74 and NGC 5068, our distances of 8.6 +/- 0.3 Mpc and 5.4 +0.2/-0.4 Mpc are the first reliable estimates to these objects; for IC 342 (3.5 +/- 0.3 Mpc), M83 (4.8 +/- 0.1 Mpc), M94 (4.4 +0.1/-0.2 Mpc), and NGC 6946 (6.1 +/- 0.6 Mpc) our values agree well with those in the literature. In the larger systems, we find no evidence for any systematic change in the PNLF with galactic position, though we do see minor field-to-field variations in the luminosity function. In most cases, these changes do not affect the measurement of distance, but in one case the fluct...

  11. High spatial resolution mid-infrared studies of planetary systems

    Science.gov (United States)

    Skemer, Andrew

    I present the results of six papers related the formation and evolution of planets and planetary systems, all of which are based on high-resolution, ground-based, mid-infrared observations. The first three chapters are studies of T Tauri binaries. T Tauri stars are young, low mass stars, whose disks form the building blocks of extrasolar planets. The first chapter is a study of the 0.68"/0.12" triple system, T Tauri. Our spatially resolved N-band photometry reveals silicate absorption towards one component, T Tau Sa, indicating the presence of an edge-on disk, which is in contrast to the other components. The second chapter is an adaptive optics fed N-band spectroscopy study of the 0.88" binary, UY Aur. We find that the dust grains around UY Aur A are ISM-like, while the mineralogy of the dust around UY Aur B is more uncertain, due to self-extinction. The third chapter presents a survey of spatially resolved silicate spectroscopy for nine T Tauri binaries. We find with 90%-95% confidence that the silicate features of the binaries are more similar than those of randomly paired single stars. This implies that a shared binary property, such as age or composition, is an important parameter in dust grain evolution. The fourth chapter is a study of the planetary system, 2MASS 1207. We explore the source of 2MASS 1207 b's under-luminosity, which has typically been explained as the result of an edge-on disk of large, grey-extincting dust grains. We find that the edge-on disk theory is incompatible with several lines of evidence, and suggest that 2MASS 1207 b's appearance can be explained by a thick cloudy atmosphere, which might be typical among young, planetary systems. The fifth chapter is a study of the white dwarf, Sirius B, which in the context of this thesis is being studied as a post-planetary system. Our N-band imaging demonstrates that Sirius B does not have an infrared excess, in contrast to previous results. The sixth chapter is a study of mid

  12. Origins of the Lunar and Planetary Laboratory, University of Arizona

    Science.gov (United States)

    Cruikshank, Dale P.; Hartmann, William K.

    2014-11-01

    The roots of the Lunar and Planetary Laboratory (LPL) extend deep into the rich fabric of G. P. Kuiper’s view of the Earth as a planet and planetary systems as expected companions to most stars, as well as the post-war emergent technology of infrared detectors suitable for astronomy. These concepts and events began with Kuiper’s theoretical work at Yerkes Observatory on the origin of the Solar System, his discovery of two planetary satellites and observational work with his near-infrared spectrometer on the then-new McDonald 82-inch telescope in the mid- to late-1940s. A grant for the production of a photographic atlas of the Moon in the mid-1950s enabled him to assemble the best existing images of the Moon and acquire new photographs. This brought E. A. Whitaker and D. W. G. Arthur to Yerkes. Others who joined in the lunar work were geologist Carl S. Huzzen and grad student E. P. Moore, as well as undergrad summer students A. B. Binder and D. P. Cruikshank (both in 1958). The Atlas was published in 1959, and work began on an orthographic lunar atlas. Kuiper’s view of planetary science as an interdisciplinary enterprise encompassing astronomy, geology, and atmospheric physics inspired his vision of a research institution and an academic curriculum tuned to the combination of all the scientific disciplines embraced in a comprehensive study of the planets. Arrangements were made with the University of Arizona (UA) to establish LPL in affiliation with the widely recognized Inst. of Atmospheric Physics. Kuiper moved to the UA in late 1960, taking the lunar experts, graduate student T. C. Owen (planetary atmospheres), and associate B. M. Middlehurst along. G. van Biesbroeck also joined the migration to Tucson; Binder and Cruikshank followed along as new grad students. Astronomy grad student W. K. Hartmann came into the academic program at UA and the research group at LPL in 1961. Senior faculty affiliating with LPL in the earliest years were T. Gehrels, A. B

  13. Impact-driven planetary desiccation: The origin of the dry Venus

    CERN Document Server

    Kurosawa, Kosuke

    2015-01-01

    The fate of surface water on Venus is one of the most important outstanding problems in comparative planetology. Here a new concept is proposed to explain water removal on a steam-covered proto Venus, referred to as impact-driven planetary desiccation. Since a steam atmosphere is photochemically unstable, water vapor dissociates into hydrogen and oxygen. Then, hydrogen escapes easily into space through hydrodynamic escape driven by strong extreme ultraviolet radiation from the young Sun. The focus is on the intense impact bombardment during the terminal stage of planetary accretion as generators of a significant amount of reducing agent. The fine-grained ejecta remove the residual oxygen, the counter part of escaped hydrogen, via the oxidation of iron-bearing rocks in a hot atmosphere. Thus, hypervelocity impacts cause net desiccation of the planetary surface. I constructed a stochastic cratering model using a Monte Carlo approach to investigate the cumulative mass of nonoxidized, ejected rocks due to the int...

  14. Teaching, Learning, and Planetary Exploration

    Science.gov (United States)

    Brown, Robert A.

    2002-01-01

    This is the final report of a program that examined the fundamentals of education associated with space activities, promoted educational policy development in appropriate forums, and developed pathfinder products and services to demonstrate the utility of advanced communication technologies for space-based education. Our focus was on space astrophysics and planetary exploration, with a special emphasis on the themes of the Origins Program, with which the Principal Investigator (PI) had been involved from the outset. Teaching, Learning, and Planetary Exploration was also the core funding of the Space Telescope Science Institute's (ST ScI) Special Studies Office (SSO), and as such had provided basic support for such important NASA studies as the fix for Hubble Space Telescope (HST) spherical aberration, scientific conception of the HST Advanced Camera, specification of the Next-Generation Space Telescope (NGST), and the strategic plan for the second decade of the HST science program.

  15. Evolution of Planetary Ringmoon Systems

    Science.gov (United States)

    Cuzzi, Jeffrey N.

    1995-01-01

    The last few decades have seen an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of these systems as our intuition (and our computers) catch up with the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is an emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system.

  16. Molecular studies of Planetary Nebulae

    CERN Document Server

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition of PNe is rather different from those of AGB and PPNe, suggesting that the molecules synthesized in PN progenitors have been heavily processed by strong ultraviolet radiation from the central star. Intriguingly, fullerenes and complex organic compounds having aromatic and aliphatic structures can be rapidly formed and largely survive during the PPN/PN evolution. The similar molecular compositions in PNe and diffuse clouds as well as the detection of C$_{60}^+$ in the ISM reinforce the view that the mass-loss from PNe can ...

  17. The PSA: Planetary Science Archive

    Science.gov (United States)

    Barthelemy, M.; Martinez, S.; Heather, D.; Vazquez, J. L.; Arviset, C.; Osuna, P.; PSA development Team

    2012-04-01

    Scientific and engineering data from ESA's planetary missions are made accessible to the world-wide scientific community via the Planetary Science Archive (PSA). The PSA consists of online services incorporating search, preview, download, notification and delivery basket functionality. Besides data from the GIOTTO spacecraft and several ground-based cometary observations, the PSA contains data from the Mars Express, Venus Express, Rosetta, SMART-1 and Huygens missions. The focus of the PSA activities is on the long-term preservation of data and knowledge from ESA's planetary missions. Scientific users can access the data online using several interfaces: - The Advanced Search Interface allows complex parameter based queries, providing the end user with a facility to complete very specific searches on meta-data and geometrical parameters. By nature, this interface requires careful use and heavy interaction with the end-user to input and control the relevant search parameters. - The Map-based Interface is currently operational only for Mars Express HRCS and OMEGA data. This interface allows an end-user to specify a region-of-interest by dragging a box onto a base map of Mars. From this interface, it is possible to directly visualize query results. The Map-based and Advanced interfaces are linked and cross-compatible. If a user defines a region-of-interest in the Map-based interface, the results can be refined by entering more detailed search parameters in the Advanced interface. - The FTP Browser Interface is designed for more experienced users, and allows for direct browsing and access of the data set content through ftp-tree search. Each dataset contains documentation and calibration information in addition to the scientific or engineering data. All data are prepared by the corresponding instrument teams, mostly located in Europe. PSA supports the instrument teams in the full archiving process, from the definition of the data products, meta-data and product labels

  18. The Auroral Planetary Imaging and Spectroscopy (APIS) service

    CERN Document Server

    Lamy, Laurent; Henry, Florence; Sidaner, Pierre Le

    2015-01-01

    The Auroral Planetary Imaging and Spectroscopy (APIS) service, accessible online, provides an open and interactive access to processed auroral observations of the outer planets and their satellites. Such observations are of interest for a wide community at the interface between planetology and magnetospheric and heliospheric physics. APIS consists of (i) a high level database, built from planetary auroral observations acquired by the Hubble Space Telescope (HST) since 1997 with its mostly used Far-UltraViolet spectro-imagers, (ii) a dedicated search interface aimed at browsing efficiently this database through relevant conditional search criteria and (iii) the ability to interactively work with the data online through plotting tools developed by the Virtual Observatory (VO) community, such as Aladin and Specview. This service is VO compliant and can therefore also been queried by external search tools of the VO community. The diversity of available data and the capability to sort them out by relevant physical...

  19. Hierarchies of Models: Toward Understanding Planetary Nebulae

    Science.gov (United States)

    Knuth, Kevin H.; Hajian, Arsen R.; Clancy, Daniel (Technical Monitor)

    2003-01-01

    Stars like our sun (initial masses between 0.8 to 8 solar masses) end their lives as swollen red giants surrounded by cool extended atmospheres. The nuclear reactions in their cores create carbon, nitrogen and oxygen, which are transported by convection to the outer envelope of the stellar atmosphere. As the star finally collapses to become a white dwarf, this envelope is expelled from the star to form a planetary nebula (PN) rich in organic molecules. The physics, dynamics, and chemistry of these nebulae are poorly understood and have implications not only for our understanding of the stellar life cycle but also for organic astrochemistry and the creation of prebiotic molecules in interstellar space. We are working toward generating three-dimensional models of planetary nebulae (PNe), which include the size, orientation, shape, expansion rate and mass distribution of the nebula. Such a reconstruction of a PN is a challenging problem for several reasons. First, the data consist of images obtained over time from the Hubble Space Telescope (HST) and spectra obtained from Kitt Peak National Observatory (KPNO) and Cerro Tololo Inter-American Observatory (CTIO). These images are of course taken from a single viewpoint in space, which amounts to a very challenging tomographic reconstruction. Second, the fact that we have two disparate and orthogonal data types requires that we utilize a method that allows these data to be used together to obtain a solution. To address these first two challenges we employ Bayesian model estimation using a parameterized physical model that incorporates much prior information about the known physics of the PN. In our previous works we have found that the forward problem of the comprehensive model is extremely time consuming. To address this challenge, we explore the use of a set of hierarchical models, which allow us to estimate increasingly more detailed sets of model parameters. These hierarchical models of increasing complexity are akin

  20. Mars 2020 Planetary Protection Status

    Science.gov (United States)

    Stricker, Moogega; Bernard, Douglas; Benardini, James Nick; Jones, Melissa

    2016-07-01

    The Mars 2020 (M2020) flight system consists of a cruise stage; an entry, descent and landing system (EDL); and a Radioisotope Thermoelectric Generator (RTG) powered roving science vehicle that will land on the surface of Mars. The M2020 Mission is designed to investigate key question related to the habitability of Mars and will conduct assessments that set the stage for potential future human exploration of Mars. Per its Program Level Requirements, the project will also acquire and cache samples of rock, regolith, and/or procedural "blank" samples for possible return to Earth by a subsequent mission. NASA has assigned the M2020 Mission as a Category V Restricted Earth Return due to the possible future return of collected samples. As indicated in NPR8020.12D, Section 5.3.3.2, the outbound leg of a Category V mission that could potentially return samples to Earth, Mars 2020 would be expected to meet the requirements of a Category IVb mission. The entire flight system is subject to microbial reduction requirements, with additional specific emphasis on the sample acquisition and caching. A bioburden accounting tool is being used to track the microbial population on the surfaces to ensure that the biological cleanliness requirements are met. Initial bioburden estimates based on MSL heritage allows M2020 to gauge more precisely how the bioburden is allocated throughout each hardware element. Mars 2020 has completed a Planetary Protection Plan with Planetary Implementation Plans at a mature draft form. Planetary protection sampling activities have commenced with the start of flight system fabrication and assembly. The status of the Planetary Protection activities will be reported.

  1. Precision photometry for planetary transits

    CERN Document Server

    Pont, F; Pont, Frederic; Moutou, Claire

    2007-01-01

    We review the state of the art in follow-up photometry for planetary transit searches. Three topics are discussed: (1) Photometric monitoring of planets discovered by radial velocity to detect possible transits (2) Follow-up photometry of candidates from photometric transit searches to weed out eclipsing binaries and false positives (3) High-precision lightcurves of known transiting planets to increase the accuracy on the planet parameters.

  2. Mechanistic Studies of Planetary Haze Formation

    Science.gov (United States)

    Hicks, Raea Kay

    2015-10-01

    Planetary atmospheres can be thought of as global-scale reactors capable of synthesizing large, complex molecules from small gases such as methane (CH4), carbon dioxide (CO2), and nitrogen (N2). The atmosphere of Titan, the largest moon of Saturn covered by a thick organic haze, contains trace amounts (2%) of CH4 in an atmosphere of N2 at a surface pressure of 1.5 bar. This is similar to the Earth's Archaean atmosphere, which possibly contained trace amounts of CH4 and CO2 (˜1,000 ppmv each) in an N2 -dominant atmosphere before the rise of biogenic oxygen. Laboratory simulations of the atmospheric chemistry on Titan and the early Earth have shown that these atmospheres are capable of generating biologically-relevant molecules that condense to form particles which can then settle to the surface of the planetary body, possibly providing the molecules required for the emergence of life. The work presented here examines the mechanisms by which FUV photochemistry initiates incorporation of N atoms into Titan aerosol analogs, and C atoms into early Earth aerosol analogs. Results from the Aerosol Collector and Pyrolyser onboard the Huygens lander reveal the presence of nitrogen in Titan's aerosols. This nitrogen incorporation is thought to occur primarily by extreme-UV photons or energetic electrons. However, recent results from our laboratory indicate a surprising amount of nitrogen incorporation- up to 16% by mass- in Titan aerosol analogs produced by photochemistry initiated by FUV irradiation of CH4/N 2 mixtures. The termolecular reaction CH+N2 +M → HCN2 has been proposed to account for this observation. Here, we test this hypothesis by using a high- resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) to measure the mass loading and chemical composition of aerosol produced at a range of pressures from roughly 0.1 to 1 atm. We report a 10-fold increase in aerosol mass loading across the range of pressures studied, indicating that the mechanism

  3. Europlanet/IDIS: Combining Diverse Planetary Observations and Models

    Science.gov (United States)

    Schmidt, Walter; Capria, Maria Teresa; Chanteur, Gerard

    2013-04-01

    Planetary research involves a diversity of research fields from astrophysics and plasma physics to atmospheric physics, climatology, spectroscopy and surface imaging. Data from all these disciplines are collected from various space-borne platforms or telescopes, supported by modelling teams and laboratory work. In order to interpret one set of data often supporting data from different disciplines and other missions are needed while the scientist does not always have the detailed expertise to access and utilize these observations. The Integrated and Distributed Information System (IDIS) [1], developed in the framework of the Europlanet-RI project, implements a Virtual Observatory approach ([2] and [3]), where different data sets, stored in archives around the world and in different formats, are accessed, re-formatted and combined to meet the user's requirements without the need of familiarizing oneself with the different technical details. While observational astrophysical data from different observatories could already earlier be accessed via Virtual Observatories, this concept is now extended to diverse planetary data and related model data sets, spectral data bases etc. A dedicated XML-based Europlanet Data Model (EPN-DM) [4] was developed based on data models from the planetary science community and the Virtual Observatory approach. A dedicated editor simplifies the registration of new resources. As the EPN-DM is a super-set of existing data models existing archives as well as new spectroscopic or chemical data bases for the interpretation of atmospheric or surface observations, or even modeling facilities at research institutes in Europe or Russia can be easily integrated and accessed via a Table Access Protocol (EPN-TAP) [5] adapted from the corresponding protocol of the International Virtual Observatory Alliance [6] (IVOA-TAP). EPN-TAP allows to search catalogues, retrieve data and make them available through standard IVOA tools if the access to the archive

  4. Do tidal or swing waves roughen planetary surfaces?

    Science.gov (United States)

    Kochemasov, Gennady G.

    2010-05-01

    heavenly bodies one might think of swing forces and swing waves (contrary to the tidal waves) producing the wave warping surfaces and the deeper planetary spheres [1]. Three observations in relation with this revelation might be mentioned. 1. An increasing surface roughness of the icy satellites of Saturn with increasing distances from the planet [5]. 2. Atmospheric masses of terrestrial planets increase with the diminishing solar distance as a sequence of more frequent wave oscillations - a sweeping out making atmospheres volatiles from planetary depths is facilitated by more frequent oscillations. 3. The inner rapidly orbiting satellites of Jupiter (Io), Saturn (Enceladus), and Neptun (Triton) are still emitting volatiles as a result of more thorough sweeping out their volatile stock. Mercury also has traces of some metals in its exosphere (MESSENGER data). References: [1] Kochemasov G.G. (2009) A regular row of planetary relief ranges connected with tectonic granulations of celestial bodies // New Concepts in Global Tectonics Newsletter, # 51, 58-61. [2] Kochemasov G.G. (2009) A quantitative geometric model of relief-forming potential in terrestrial planets // EPSC Abstracts, Vol. 4, EPSC2009-16-1. [3] Kochemasov G.G. (1998) Tectonic dichotomy, sectoring and granulation of Earth and other celestial bodies // Proceedings of the International Symposium on New Concepts in Global Tectonics, "NCGT-98 TSUKUBA", Geological Survey of Japan, Tsukuba, Nov 20-23, 1998, 144-147. [4] Kochemasov G.G. (1993) Relief-forming potential of planets // 18th Russian-American microsymposium on planetology, Abstracts, Oct. 9-10, 1993, Moscow, Vernadsky Inst. (GEOKHI), 27-28. [5] Thomas, P.C., Veverka, J., Helfenstein, P., Porco, C. et al. (2006) Shapes of the saturnian icy satellites // Lunar and Planetary Science Conference XXXVII, Houston, USA, Abstract 1639 pdf. CD-ROM.

  5. Planetary Exploration in the Classroom

    Science.gov (United States)

    Slivan, S. M.; Binzel, R. P.

    1997-07-01

    We have developed educational materials to seed a series of undergraduate level exercises on "Planetary Exploration in the Classroom." The goals of the series are to teach modern methods of planetary exploration and discovery to students having both science and non-science backgrounds. Using personal computers in a "hands-on" approach with images recorded by planetary spacecraft, students working through the exercises learn that modern scientific images are digital objects that can be examined and manipulated in quantitative detail. The initial exercises we've developed utilize NIH Image in conjunction with images from the Voyager spacecraft CDs. Current exercises are titled "Using 'NIH IMAGE' to View Voyager Images", "Resolving Surface Features on Io", "Discovery of Volcanoes on Io", and "Topography of Canyons on Ariel." We expect these exercises will be released during Fall 1997 and will be available via 'anonymous ftp'; detailed information about obtaining the exercises will be on the Web at "http://web.mit.edu/12s23/www/pec.html." This curriculum development was sponsored by NSF Grant DUE-9455329.

  6. Ionospheric absorption and planetary wave activity in East Asia sector

    Institute of Scientific and Technical Information of China (English)

    HAO YongQiang; ZHANG DongHe

    2012-01-01

    In this paper,we focus on ionospheric absorption in the East Asia sector,and look for manifestations of atmospheric influences in this area.First,a 4-year historical record of absorption measurement at Beijing is presented.This record was obtained by a sweep frequency technique,in which 27-days periodic variation of the absorption level was found to be dominant,appearing in most seasons except winters.Instead,unusual enhancements of the absorption level appeared in winters (winter anomaly),at the meantime the level varied with periods mainly in the range of 8-12 days.Comparing to 27-days period from the Sun,the shorter period oscillations should be related to planetary wave activities in lower atmosphere.Second,fmin data from 5 mid-latitude ionosondes in Japan were used as an indirect but long-term measurement.With the fmin data covering two solar cycles,disturbances with various periods were found to be active around solar maximum years,but the 8-12 days oscillations always existed in winter,showing seasonal dependence instead of connection to solar activity.These results given in this paper demonstrate seasonal and solar cycle-dependent features of the ionospheric absorption in East Asia sector,and confirm the existence of influence from atmosphere-ionosphere coupling in this area,as well as the relationship between ionospheric winter anomaly and planetary wave activity.

  7. Internal wave coupling processes in Earth's atmosphere

    CERN Document Server

    Yiğit, Erdal

    2014-01-01

    This paper presents a contemporary review of vertical coupling in the atmosphere and ionosphere system induced by internal waves of lower atmospheric origin. Atmospheric waves are primarily generated by meteorological processes, possess a broad range of spatial and temporal scales, and can propagate to the upper atmosphere. A brief summary of internal wave theory is given, focusing on gravity waves, solar tides, planetary Rossby and Kelvin waves. Observations of wave signatures in the upper atmosphere, their relationship with the direct propagation of waves into the upper atmosphere, dynamical and thermal impacts as well as concepts, approaches, and numerical modeling techniques are outlined. Recent progress in studies of sudden stratospheric warming and upper atmospheric variability are discussed in the context of wave-induced vertical coupling between the lower and upper atmosphere.

  8. The Atmospheres of Extrasolar Planets

    Science.gov (United States)

    Richardson, L. J.; Seager, S.

    2007-01-01

    In this chapter we examine what can be learned about extrasolar planet atmospheres by concentrating on a class of planets that transit their parent stars. As discussed in the previous chapter, one way of detecting an extrasolar planet is by observing the drop in stellar intensity as the planet passes in front of the star. A transit represents a special case in which the geometry of the planetary system is such that the planet s orbit is nearly edge-on as seen from Earth. As we will explore, the transiting planets provide opportunities for detailed follow-up observations that allow physical characterization of extrasolar planets, probing their bulk compositions and atmospheres.

  9. Atmosphere in a Test Tube

    Science.gov (United States)

    Claudi, R.; Pace, E.; Ciaravella, A.; Micela, G.; Piccioni, G.; Billi, D.; Cestelli Guidi, M.; Coccola, L.; Erculiani, M. S.; Fedel, M.; Galletta, G.; Giro, E.; La Rocca, N.; Morosinotto, T.; Poletto, L.; Schierano, D.; Stefani, S.

    The ancestor philosophers' dream of thousand of new world is finally realised: more than 1800 extrasolar planets have been discovered in the neighborhood of our Sun. Most of them are very different from those we used to know in our Solar System. Others orbit the Habitable Zone (HZ) of their parent stars. Space missions, as JWST and the very recently proposed ARIEL, or ground based instruments, like SPHERE@VLT, GPI@GEMINI and EPICS@ELT, have been proposed and built to measure the atmospheric transmission, reflection and emission spectra over a wide wavelength range of these new worlds. In order to interpret the spectra coming out by this new instrumentation, it is important to know in detail the optical characteristics of gases in the typical physical conditions of the planetary atmospheres and how those characteristics could be affected by radiation driven photochemical and bio-chemical reaction. Insights in this direction can be achieved from laboratory studies of simulated planetary atmosphere of different pressure and temperature conditions under the effects of radiation sources, used as proxies of different bands of the stellar emission. ''Atmosphere in a Test Tube'' is a collaboration among several Italian astronomical, biological and engineering institutes in order to share their experiencece in performing laboratory experiments on several items concerning extrasolar planet atmospheres.

  10. ADVANCED RADIOISOTOPE HEAT SOURCE AND PROPULSION SYSTEMS FOR PLANETARY EXPLORATION

    Energy Technology Data Exchange (ETDEWEB)

    R. C. O' Brien; S. D. Howe; J. E. Werner

    2010-09-01

    The exploration of planetary surfaces and atmospheres may be enhanced by increasing the range and mobility of a science platform. Fundamentally, power production and availability of resources are limiting factors that must be considered for all science and exploration missions. A novel power and propulsion system is considered and discussed with reference to a long-range Mars surface exploration mission with in-situ resource utilization. Significance to applications such as sample return missions is also considered. Key material selections for radioisotope encapsulation techniques are presented.

  11. Laboratory diode laser spectroscopy in molecular planetary astronomy

    Science.gov (United States)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopy of planetary atmospheres is performed at high spectral resolution comparable to that in the laboratory. This requires that laboratory spectroscopy use the highest resolution and the most accurate techniques. Tunable diode laser spectroscopy can supply many of the spectroscopic parameters needed by astronomers. In particular, line positions, line strengths, and collisional line widths are measured with diode lasers, and these are often among the best values available. Diode laser spectra are complimentary to lower resolution, broader-coverage Fourier transform spectra. Certain procedures must be adopted, however, when using diode lasers, for determining their output characteristics and for calibrating each spectrum against quality references.

  12. Emirates Mars Mission Planetary Protection Plan

    Science.gov (United States)

    Awadhi, Mohsen Al

    2016-07-01

    The United Arab Emirates is planning to launch a spacecraft to Mars in 2020 as part of the Emirates Mars Mission (EMM). The EMM spacecraft, Amal, will arrive in early 2021 and enter orbit about Mars. Through a sequence of subsequent maneuvers, the spacecraft will enter a large science orbit and remain there throughout the primary mission. This paper describes the planetary protection plan for the EMM mission. The EMM science orbit, where Amal will conduct the majority of its operations, is very large compared to other Mars orbiters. The nominal orbit has a periapse altitude of 20,000 km, an apoapse altitude of 43,000 km, and an inclination of 25 degrees. From this vantage point, Amal will conduct a series of atmospheric investigations. Since Amal's orbit is very large, the planetary protection plan is to demonstrate a very low probability that the spacecraft will ever encounter Mars' surface or lower atmosphere during the mission. The EMM team has prepared methods to demonstrate that (1) the launch vehicle targets support a 0.01% probability of impacting Mars, or less, within 50 years; (2) the spacecraft has a 1% probability or less of impacting Mars during 20 years; and (3) the spacecraft has a 5% probability or less of impacting Mars during 50 years. The EMM mission design resembles the mission design of many previous missions, differing only in the specific parameters and final destination. The following sequence describes the mission: 1.The mission will launch in July, 2020. The launch includes a brief parking orbit and a direct injection to the interplanetary cruise. The launch targets are specified by the hyperbolic departure's energy C3, and the hyperbolic departure's direction in space, captured by the right ascension and declination of the launch asymptote, RLA and DLA, respectively. The targets of the launch vehicle are biased away from Mars such that there is a 0.01% probability or less that the launch vehicle arrives onto a trajectory that impacts Mars

  13. Atmospheric discharge and dispersion of radionuclides during the Fukushima Dai-ichi Nuclear Power Plant accident. Part II: verification of the source term and analysis of regional-scale atmospheric dispersion.

    Science.gov (United States)

    Terada, Hiroaki; Katata, Genki; Chino, Masamichi; Nagai, Haruyasu

    2012-10-01

    Regional-scale atmospheric dispersion simulations were carried out to verify the source term of (131)I and (137)Cs estimated in our previous studies, and to analyze the atmospheric dispersion and surface deposition during the Fukushima Dai-ichi Nuclear Power Plant accident. The accuracy of the source term was evaluated by comparing the simulation results with measurements of daily and monthly surface depositions (fallout) over land in eastern Japan from March 12 to April 30, 2011. The source term was refined using observed air concentrations of radionuclides for periods when there were significant discrepancies between the calculated and measured daily surface deposition, and when environmental monitoring data, which had not been used in our previous studies, were now available. The daily surface deposition using the refined source term was predicted mostly to within a factor of 10, and without any apparent bias. Considering the errors in the model prediction, the estimated source term is reasonably accurate during the period when the plume flowed over land in Japan. The analysis of regional-scale atmospheric dispersion and deposition suggests that the present distribution of a large amount of (137)Cs deposition in eastern Japan was produced primarily by four events that occurred on March 12, 15-16, 20, and 21-23. The ratio of wet deposition to the total varied widely depending on the influence by the particular event. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Wind-Induced Atmospheric Escape: Titan

    Science.gov (United States)

    Hartle, Richard; Johnson, Robert; Sittler, Edward, Jr.; Sarantos, Menelaos; Simpson, David

    2012-01-01

    Rapid thermospheric flows can significantly enhance the estimates of the atmospheric loss rate and the structure of the atmospheric corona of a planetary body. In particular, rapid horizontal flow at the exobase can increase the corresponding constituent escape rate. Here we show that such corrections, for both thermal and non-thermal escape, cannot be ignored when calculating the escape of methane from Titan, for which drastically different rates have been proposed. Such enhancements are also relevant to Pluto and exoplanets.

  15. Planetary engulfment as a trigger for white dwarf pollution

    CERN Document Server

    Petrovich, Cristobal

    2016-01-01

    The presence of a planetary system can shield a planetesimal disk from the secular gravitational perturbations due to distant outer massive objects (planets or stellar companions). As the host star evolves off the main sequence to become a white dwarf, these planets can be engulfed, triggering secular instabilities and leading to the tidal disruptions of small rocky bodies. These disrupted bodies can feed the white dwarfs with rocky material and possibly explain the high-metallicity material in their atmospheres. We illustrate how this mechanism can operate when the gravitational perturbations are due to the Kozai-Lidov mechanism from a stellar binary companion. We show that this mechanism can explain the observed levels of accretion if: (1) the planetary engulfment happens fast compared to the secular timescale, which is generally the case for wide binaries ($>100$ AU) and planetary engulfment during the Asymptotic Giant Branch; (2) the planetesimal disk has a total mass of $\\sim10^{-4}-10^{-2}M_\\oplus$. We ...

  16. Planetary Engulfment as a Trigger for White Dwarf Pollution

    Science.gov (United States)

    Petrovich, Cristobal; Muñoz, Diego J.

    2017-01-01

    The presence of a planetary system can shield a planetesimal disk from the secular gravitational perturbations due to distant outer massive objects (planets or stellar companions). As the host star evolves off the main sequence to become a white dwarf, these planets can be engulfed during the giant phase, triggering secular instabilities and leading to the tidal disruptions of small rocky bodies. These disrupted bodies can feed the white dwarfs with rocky material and possibly explain the high-metallicity material in their atmospheres. We illustrate how this mechanism can operate when the gravitational perturbations are due to the KL mechanism from a stellar binary companion, a process that is activated only after the planet has been removed/engulfed. We show that this mechanism can explain the observed accretion rates if: (1) the planetary engulfment happens rapidly compared to the secular timescale, which is generally the case for wide binaries (> 100 au) and planetary engulfment during the asymptotic giant branch; (2) the planetesimal disk has a total mass of ∼ {10}-4-{10}-2{M}\\oplus . We show that this new mechanism can provide a steady supply of material throughout the entire life of the white dwarfs for all cooling ages and can account for a large fraction (up to nearly half) of the observed polluted white dwarfs.

  17. Planetary Space Weather Service: Part of the the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    Grande, Manuel; Andre, Nicolas

    2016-07-01

    Over the next four years the Europlanet 2020 Research Infrastructure will set up an entirely new European Planetary Space Weather service (PSWS). Europlanet RI is a part of of Horizon 2020 (EPN2020-RI, http://www.europlanet-2020-ri.eu). The Virtual Access Service, WP5 VA1 "Planetary Space Weather Services" will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. VA1 will make five entirely new 'toolkits' accessible to the research community and to industrial partners planning for space missions: a general planetary space weather toolkit, as well as three toolkits dedicated to the following key planetary environments: Mars (in support ExoMars), comets (building on the expected success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUICE mission to be launched in 2022). This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather in the tools and models available within the partner institutes. It will also create a novel event-diary toolkit aiming at predicting and detecting planetary events like meteor showers and impacts. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. So WP10 JRA4 "Planetary Space Weather Services" (PSWS) will provide the additional research and tailoring required to apply them for these purposes. The overall objectives of this Joint Research Aactivities will be to review, test, improve and adapt methods and tools

  18. The Roles of Discs for Planetary Systems

    CERN Document Server

    Yeh, L C; Yeh, Li-Chin; Jiang, Ing-Guey

    2007-01-01

    It is known that the discs are detected for some of the extra-solar planetary systems. It is also likely that there was a disc mixing with planets and small bodies while our Solar System was forming. From our recent results, we conclude that the discs play two roles: the gravity makes planetary systems more chaotic and the drag makes planetary systems more resonant.

  19. Planetary Temperatures : Early Estimates, Lowell, and the Albedo of the Earth

    Science.gov (United States)

    Lorenz, Ralph

    2016-10-01

    While it was recognized by Huygens, as soon as the architecture of the solar system was understood, that outer planets would be much cooler than Earth, quantitative estimation of planetary temperatures only became possible with understanding of radiant heat, and specifically the Stefan law relating heat flux to the fourth power of absolute temperature. This relation appears to have been first applied to planetary temperatures by the Danish physicist Christiansen in 1885, and he derived results for Mars and Saturn of -40 and -180C, rather reasonable values. However, the separate values of the solar constant, absolute planetary albedos (including that of the Earth) and the short- and long-wave transparency of planetary atmospheres were not known, although mountaintop measurements by Langley made some first steps to quantifying these effects. Lowell recognized that the Martian atmosphere was thinner than ours, but had more carbon dioxide, and so considered these factors to cancel out. However, he suggested that the Earth had a reflectivity of some 75%, such that darker Mars would absorb a larger fraction of incident sunlight than the Earth, compensating for Mars' greater distance from the sun and thus allowing clement temperatures. It is difficult not to see this as pushing the numbers to obtain a desired result, and indeed a robust refutation of his calculations swiftly followed by Poynting and Alfred Russel Wallace. I present a brief review of these early days of planetary climate modeling.

  20. Twenty-Second Lunar and Planetary Science Conference

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The papers in this collection were written for general presentation, avoiding jargon and unnecessarily complex terms. Some of the topics covered include: planetary evolution, planetary satellites, planetary composition, planetary surfaces, planetary geology, volcanology, meteorite impacts and composition, and cosmic dust. Particular emphasis is placed on Mars and the Moon.

  1. Sealed Planetary Return Canister (SPRC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample return missions have primary importance in future planetary missions. A basic requirement is that samples be returned in pristine, uncontaminated condition,...

  2. Institute of Geophysics, Planetary Physics, and Signatures

    Data.gov (United States)

    Federal Laboratory Consortium — The Institute of Geophysics, Planetary Physics, and Signatures at Los Alamos National Laboratory is committed to promoting and supporting high quality, cutting-edge...

  3. Nasa's Planetary Geologic Mapping Program: Overview

    Science.gov (United States)

    Williams, D. A.

    2016-06-01

    NASA's Planetary Science Division supports the geologic mapping of planetary surfaces through a distinct organizational structure and a series of research and analysis (R&A) funding programs. Cartography and geologic mapping issues for NASA's planetary science programs are overseen by the Mapping and Planetary Spatial Infrastructure Team (MAPSIT), which is an assessment group for cartography similar to the Mars Exploration Program Assessment Group (MEPAG) for Mars exploration. MAPSIT's Steering Committee includes specialists in geological mapping, who make up the Geologic Mapping Subcommittee (GEMS). I am the GEMS Chair, and with a group of 3-4 community mappers we advise the U.S. Geological Survey Planetary Geologic Mapping Coordinator (Dr. James Skinner) and develop policy and procedures to aid the planetary geologic mapping community. GEMS meets twice a year, at the Annual Lunar and Planetary Science Conference in March, and at the Annual Planetary Mappers' Meeting in June (attendance is required by all NASA-funded geologic mappers). Funding programs under NASA's current R&A structure to propose geological mapping projects include Mars Data Analysis (Mars), Lunar Data Analysis (Moon), Discovery Data Analysis (Mercury, Vesta, Ceres), Cassini Data Analysis (Saturn moons), Solar System Workings (Venus or Jupiter moons), and the Planetary Data Archiving, Restoration, and Tools (PDART) program. Current NASA policy requires all funded geologic mapping projects to be done digitally using Geographic Information Systems (GIS) software. In this presentation we will discuss details on how geologic mapping is done consistent with current NASA policy and USGS guidelines.

  4. Robotic Tool Changer for Planetary Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future planetary exploration missions will require compact, lightweight robotic manipulators for handling a variety of tools & instruments without increasing the...

  5. Sealed Planetary Return Canister (SPRC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample return missions have primary importance in future planetary missions. A basic requirement is that samples be returned in pristine, uncontaminated condition,...

  6. Teaching, learning, and planetary exploration

    Science.gov (United States)

    Brown, Robert A.

    1992-01-01

    The progress accomplished in the first five months of the three-year grant period of Teaching, Learning, and Planetary Exploration is presented. The objectives of this project are to discover new education products and services based on space science, particularly planetary exploration. An Exploration in Education is the umbrella name for the education projects as they are seen by teachers and the interested public. As described in the proposal, our approach consists of: (1) increasing practical understanding of the potential role and capabilities of the research community to contribute to basic education using new discoveries; (2) developing an intellectual framework for these contributions by supplying criteria and templates for the teacher's stories; (3) attracting astronomers, engineers, and technical staff to the project and helping them form productive education partnerships for the future, (4) exploring relevant technologies and networks for authoring and communicating the teacher's stories; (5) enlisting the participation of potential user's of the teacher's stories in defining the products; (6) actually producing and delivering many educationally useful teacher's stories; and (7) reporting the pilot study results with critical evaluation. Technical progress was made by assembling our electronic publishing stations, designing electronic publications based on space science, and developing distribution approaches for electronic products. Progress was made addressing critical issues by developing policies and procedures for securing intellectual property rights and assembling a focus group of teachers to test our ideas and assure the quality of our products. The following useful materials are being produced: the TOPS report; three electronic 'PictureBooks'; one 'ElectronicArticle'; three 'ElectronicReports'; ten 'PrinterPosters'; and the 'FaxForum' with an initial complement of printed materials. We have coordinated with planetary scientists and astronomers

  7. Planetary Radars Operating Centre PROC

    Science.gov (United States)

    Catallo, C.; Flamini, E.; Seu, R.; Alberti, G.

    2007-12-01

    Planetary exploration by means of radar systems, mainly using Ground Penetrating Radars (GPR) plays an important role in Italy. Numerous scientific international space programs are currently carried out jointly with ESA and NASA by Italian Space Agency, the scientific community and the industry. Three important experiments under Italian leadership ( designed and manufactured by the Italian industry), provided by ASI either as contribution to ESA programs either within a NASA/ASI joint venture framework, are now operating: MARSIS on-board Mars Express, SHARAD on-board Mars Reconnaissance Orbiter and CASSINI Radar on-board Cassini spacecraft. In order to support all the scientific communities, institutional customers and experiment teams operation three Italian dedicated operational centers have been realized, namely SHOC, (Sharad Operating Centre), MOC (Marsis Operating Center) and CASSINI PAD ( Processing Altimetry Data). Each center is dedicated to a single instrument management and control, data processing and distribution. Although they had been conceived to operate autonomously and independently one from each other, synergies and overlaps have been envisaged leading to the suggestion of a unified center, the Planetary Radar Processing Center (PROC). PROC is conceived in order to include the three operational centers, namely SHOC, MOC and CASSINI PAD, either from logistics point of view and from HW/SW capabilities point of view. The Planetary Radar Processing Center shall be conceived as the Italian support facility to the scientific community for on-going and future Italian planetary exploration programs. Therefore, scalability, easy use and management shall be the design drivers. The paper describes how PROC is designed and developed, to allow SHOC, MOC and CASSINI PAD to operate as before, and to offer improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation. Furthermore, in the frame of

  8. Central Stars of Planetary Nebulae

    CERN Document Server

    Jones, David

    2016-01-01

    In this brief invited review, I will attempt to summarise some of the key areas of interest in the study of central stars of planetary nebulae which (probably) won't be covered by other speakers' proceedings. The main focus will, inevitably, be on the subject of multiplicity, with special emphasis on recent results regarding triple central star systems as well as wide binaries which avoid a common-envelope phase. Furthermore, in light of the upcoming release of Kepler's Campaign 11 data, I will discuss a few of the prospects from that data including the unique possibility to detect merger products.

  9. Scientific Value of a Saturn Atmospheric Probe Mission

    Science.gov (United States)

    Simon-Miller, A. A.; Lunine, J. I.; Atreya, S. K.; Spilker, T. R.; Coustenis, A.; Atkinson, D. H.

    2012-01-01

    Atmospheric entry probe mISSions to the giant planets can uniquely discriminate between competing theories of solar system formation and the origin and evolution of the giant planets and their atmospheres. This provides for important comparative studies of the gas and ice giants, and to provide a laboratory for studying the atmospheric chemistries, dynamics, and interiors of all the planets including Earth. The giant planets also represent a valuable link to extrasolar planetary systems. As outlined in the recent Planetary Decadal Survey, a Saturn Probe mission - with a shallow probe - ranks as a high priority for a New Frontiers class mission [1].

  10. Contribution of the infrasound technology to characterize large scale atmospheric disturbances and impact on infrasound monitoring

    Science.gov (United States)

    Blanc, Elisabeth; Le Pichon, Alexis; Ceranna, Lars; Pilger, Christoph; Charlton Perez, Andrew; Smets, Pieter

    2016-04-01

    The International Monitoring System (IMS) developed for the verification of the Comprehensive nuclear-Test-Ban Treaty (CTBT) provides a unique global description of atmospheric disturbances generating infrasound such as extreme events (e.g. meteors, volcanoes, earthquakes, and severe weather) or human activity (e.g. explosions and supersonic airplanes). The analysis of the detected signals, recorded at global scales and over near 15 years at some stations, demonstrates that large-scale atmospheric disturbances strongly affect infrasound propagation. Their time scales vary from several tens of minutes to hours and days. Their effects are in average well resolved by the current model predictions; however, accurate spatial and temporal description is lacking in both weather and climate models. This study reviews recent results using the infrasound technology to characterize these large scale disturbances, including (i) wind fluctuations induced by gravity waves generating infrasound partial reflections and modifications of the infrasound waveguide, (ii) convection from thunderstorms and mountain waves generating gravity waves, (iii) stratospheric warming events which yield wind inversions in the stratosphere, (iv)planetary waves which control the global atmospheric circulation. Improved knowledge of these disturbances and assimilation in future models is an important objective of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project. This is essential in the context of the future verification of the CTBT as enhanced atmospheric models are necessary to assess the IMS network performance in higher resolution, reduce source location errors, and improve characterization methods.

  11. Exoplanet Atmospheres and Giant Ground-Based Telescopes

    CERN Document Server

    Crossfield, I J M

    2016-01-01

    The study of extrasolar planets has rapidly expanded to encompass the search for new planets, measurements of sizes and masses, models of planetary interiors, planetary demographics and occurrence frequencies, the characterization of planetary orbits and dynamics, and studies of these worlds' complex atmospheres. Our insights into exoplanets dramatically advance whenever improved tools and techniques become available, and surely the largest tools now being planned are the optical/infrared Extremely Large Telescopes (ELTs). Two themes summarize the advantages of atmospheric studies with the ELTs: high angular resolution when operating at the diffraction limit and high spectral resolution enabled by the unprecedented collecting area of these large telescopes. This brief review describes new opportunities afforded by the ELTs to study the composition, structure, dynamics, and evolution of these planets' atmospheres, while specifically focusing on some of the most compelling atmospheric science cases for four qua...

  12. Saturn's magnetosphere: An example of dynamic planetary systems

    Science.gov (United States)

    Krimigis, Stamatios M.

    2011-01-01

    Planetary magnetospheres are prime examples of interacting plasma regimes at different scales. There is the principal interaction with the solar wind that seems to be the main driver of the dynamics at Mercury and Earth. But these inner planet magnetospheres are relatively simple when compared to those of the outer planets which are primarily driven by planetary rotation and include internal plasma sources from various moons and rings, in addition to those from the planetary ionospheres and the solar wind. Io's volcanic source at Jupiter is a prime example, but now Enceladus at Saturn has joined the fray, while Titan is a surprisingly minor player despite its thick nitrogen atmosphere and its continued bombardment by energetic particles. Mass loading of plasma leads to interchange instability in the inner magnetospheres at both Jupiter and Saturn, while ionospheric slippage, among other processes, seems to contribute to a variable rotation period in the spin-aligned dipole field of Saturn, manifested in auroral kilometric radiation (SKR), components of the magnetic field itself, and the plasma periodicities measured at several energies. Through use of the ENA (energetic neutral atom) technique, it is now possible to observe bulk motions of the plasma and their connection to planetary auroral processes. Such imaging at Saturn by Cassini has revealed the location of a region of post-midnight acceleration events that seem to corotate with the planet and coincide with auroral brightening and SKR. Periodic injections of plasma have been identified and repeat at the Kronian rotation period of 10.8 hours. A semi-permanent but asymmetric ring current has also been imaged, located between the orbits of the satellites Rhea (~9 RS) and Titan (~20 RS), with a maximum at ~10+/- 1RS and dominated by the hot (>3 keV) plasma component.

  13. Kn 26, a New Quadrupolar Planetary Nebula

    CERN Document Server

    Guerrero, Martin A; Ramos-Larios, Gerardo; Vazquez, Roberto

    2013-01-01

    Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has been only recently recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time-lap between the ejection of the two pairs of bipolar lobes is much smaller than their dynamical ages, implying a rapid change of the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as of type II PNe) and a high helium abundance (as of type I PNe), although not atypica...

  14. Equations of State: Gateway to Planetary Origin and Evolution (Invited)

    Science.gov (United States)

    Melosh, J.

    2013-12-01

    Research over the past decades has shown that collisions between solid bodies govern many crucial phases of planetary origin and evolution. The accretion of the terrestrial planets was punctuated by planetary-scale impacts that generated deep magma oceans, ejected primary atmospheres and probably created the moons of Earth and Pluto. Several extrasolar planetary systems are filled with silicate vapor and condensed 'tektites', probably attesting to recent giant collisions. Even now, long after the solar system settled down from its violent birth, a large asteroid impact wiped out the dinosaurs, while other impacts may have played a role in the origin of life on Earth and perhaps Mars, while maintaining a steady exchange of small meteorites between the terrestrial planets and our moon. Most of these events are beyond the scale at which experiments are possible, so that our main research tool is computer simulation, constrained by the laws of physics and the behavior of materials during high-speed impact. Typical solar system impact velocities range from a few km/s in the outer solar system to 10s of km/s in the inner system. Extrasolar planetary systems expand that range to 100s of km/sec typical of the tightly clustered planetary systems now observed. Although computer codes themselves are currently reaching a high degree of sophistication, we still rely on experimental studies to determine the Equations of State (EoS) of materials critical for the correct simulation of impact processes. The recent expansion of the range of pressures available for study, from a few 100 GPa accessible with light gas guns up to a few TPa from current high energy accelerators now opens experimental access to the full velocity range of interest in our solar system. The results are a surprise: several groups in both the USA and Japan have found that silicates and even iron melt and vaporize much more easily in an impact than previously anticipated. The importance of these findings is

  15. Kinematical Properties of Planetary Nebulae with WR-type Nuclei

    CERN Document Server

    Danehkar, Ashkbiz; Parker, Quentin A

    2014-01-01

    We have carried out integral field unit (IFU) spectroscopy of H$\\alpha$, [N II] and [O III] emission lines for a sample of Galactic planetary nebulae (PNe) with Wolf-Rayet (WR) stars and weak emission-line stars (wels). Comparing their spatially-resolved kinematic observations with morpho-kinematic models allowed us to disentangle their three-dimensional gaseous structures. Our results indicate that these PNe have axisymmetric morphologies, either bipolar or elliptical. In many cases the associated kinematic maps for the PNe around hot central stars also reveal the presence of so-called fast low-ionization emission regions.

  16. Radiation-Hydrodynamics of Hot Jupiter Atmospheres

    CERN Document Server

    Menou, Kristen

    2009-01-01

    Radiative transfer in planetary atmospheres is usually treated in the static limit, i.e., neglecting atmospheric motions. We argue that hot Jupiter atmospheres, with possibly fast (sonic) wind speeds, may require a more strongly coupled treatment, formally in the regime of radiation-hydrodynamics. To lowest order in v/c, relativistic Doppler shifts distort line profiles along optical paths with finite wind velocity gradients. This leads to flow-dependent deviations in the effective emission and absorption properties of the atmospheric medium. Evaluating the overall impact of these distortions on the radiative structure of a dynamic atmosphere is non-trivial. We present transmissivity and systematic equivalent width excess calculations which suggest possibly important consequences for radiation transport in hot Jupiter atmospheres. If winds are fast and bulk Doppler shifts are indeed important for the global radiative balance, accurate modeling and reliable data interpretation for hot Jupiter atmospheres may p...

  17. Carbon Dioxide: The Other Planetary Fluid

    Science.gov (United States)

    Glaser, S.; Gamez, D.; Shock, E.

    2016-12-01

    Cometary and interstellar ices have carbon dioxide to water mole ratios of up to 0.3. When melted, such high levels of carbon dioxide cannot all be dissolved in the aqueous phase and instead partition into a CO2-rich (carbonic) fluid. This implies that during the accretion and formation of planetary systems carbonic fluids are not only possible, but common. In fact, they make up the atmosphere of Venus, are found bubbli