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Sample records for jupiter thermospheric general

  1. Ionosphere-Thermosphere Coupling in Jupiter's Low Latitudes

    Science.gov (United States)

    Stallard, T.; Melin, H.; Johnson, R.; O'Donoghue, J.; Moore, L.; Miller, S.; Tao, C.; Achilleos, N. A.; Smith, C.; Ray, L. C.; Yates, J. N.

    2015-12-01

    One of the leading problems in our understanding of Jupiter's atmosphere, known colloquially as the 'energy crisis', is that the upper atmosphere has global temperatures far in excess of that predicted by solar heating. Unlike the Earth, solar heating has only a small effect on the thermosphere, varying little in temperature with local time, and with equatorial neutrals co-rotating with the planet due to meridional advection. Within the auroral region, ionosphere-thermosphere coupling produces strong flows and results in huge Joule Heating from auroral currents. In this region, the temperature excess can be explained, but Jupiter's fast rotation means that Coriolis forces prevent energy in the poles from transferring equatorward, so there remains no explanation of why low latitudes are overheated by a factor of 3-5 over that predicted by solar heating alone.Despite this anomaly, although the past twenty years has seen a wealth of new data and results in Jupiter's auroral region, studies of the equatorial region have been somewhat limited. This lack of investigation comes partly from the apparent uniform nature of the equatorial region, and partly from the difficulty in observing this region. It is only in the past three years that observers begun to re-examine this region, revealing evidence of complex interactions between the thermosphere and ionosphere, including what appears to be thermospheric weather patterns at a fixed planetary longitudes, stable over two decades; perhaps caused by continuous flows from the auroral region. Here, we introduce our recent research, in order to compare and contrast what has been observed at Jupiter with the more well understood interactions between Earth's ionosphere and thermosphere. We hope that this will open a discussion between the communities that will improve our understanding of the underlying physical processes, as they occur at both planets.

  2. Influence of upstream solar wind on thermospheric flows at Jupiter

    CERN Document Server

    Yates, J N; Guio, P

    2010-01-01

    The coupling of Jupiter's magnetosphere and ionosphere plays a vital role in creating its auroral emissions. The strength of these emissions is dependent on the difference in speed of the rotational flows within Jupiter's high-latitude thermosphere and the planet's magnetodisc. Using an azimuthally symmetric global circulation model, we have simulated how upstream solar wind conditions affect the energy and direction of atmospheric flows. In order to simulate the effect of a varying dynamic pressure in the upstream solar wind, we calculated three magnetic field profiles representing compressed, averaged and expanded `middle' magnetospheres. These profiles were then used to solve for the angular velocity of plasma in the magnetosphere. This angular velocity determines the strength of currents flowing between the ionosphere and magnetosphere. We examine the influence of variability in this current system upon the global winds and energy inputs within the Jovian thermosphere. We find that the power dissipated by...

  3. Development of the Non-Hydrostatic Jupiter Global Ionosphere Thermosphere Model (J-GITM): Status and Current Simulations

    Science.gov (United States)

    Bougher, Stephen; Ridley, Aaron; Majeed, Tariq; Waite, J. Hunter; Gladstone, Randy; Bell, Jared

    2016-07-01

    The primary objectives for development and validation of a new 3-D non-hydrostatic model of Jupiter's upper atmosphere is to improve our understanding of Jupiter's thermosphere-ionosphere-magnetosphere system and to provide a global context within which to analyze the data retrieved from the new JUNO mission. The new J-GITM model presently incorporates the progress made on the previous Jupiter-TGCM code (i.e. key parameterizations, ion-neutral chemistry, IR cooling) while also employing the non-hydrostatic numerical core of the Earth Global Ionosphere-Thermosphere Model (GITM). The GITM numerical framework has been successfully applied to Earth, Mars, and Titan (see Ridley et al. [2006], Bougher et al. [2015], Bell [2008, 2010]). Moreover, it has been shown to simulate the effects of strong, localized heat sources (such as joule heating and auroral heating) more accurately than strictly hydrostatic GCMs (Deng et al. [2007, 2008]). Thus far, in the J-GITM model development and testing, model capability has been progressively augmented to capture the neutral composition (e.g. H, H2, He major species), 3-component neutral winds, and thermal structure, as well as the ion composition (H3+, H2+, and H+ among others) above 250 km. Presently, J-GITM: (a) provides an interactive calculation for auroral particle precipitation (i.e. heating, ionization), an improvement over the static formulation used previously in the J-TGCM (Bougher et al., 2005; Majeed et al., 2005, 2009, 2015); (b) self-consistently calculates an ionosphere using updated ion-neutral chemistry, ion dynamics, and electron transport; (c) simulates the chemistry that forms key hydrocarbons at the base of the thermosphere, focusing on CH4, C2H2, and C2H6; (d) allows the production of H3+, CH4, C2H2, and C2H6 to modify the global thermal balance of Jupiter through their non-LTE radiative cooling; (e) provides a calculation of H2 vibrational chemistry to regulate H+ densities; and (f) uses the improved

  4. Improved short-term variability in the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model

    NARCIS (Netherlands)

    Häusler, K.; Hagan, M.E.; Baumgaertner, A.J.G.; Maute, A.; Lu, G.; Doornbos, E.N.; Bruinsma, S.; Forbes, J.M.; Gasperini, F.

    2014-01-01

    We report on a new source of tidal variability in the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM). Lower boundary forcing of the TIME-GCM for a simulation of November–December 2009 based on 3-hourly Modern-Era Retro

  5. Jupiter

    CERN Document Server

    Penne, Barbra

    2017-01-01

    Our solar system's largest planet is huge enough that all of the system's other planets could fit inside it. Although Jupiter has been known since ancient times, scientists are still learning exciting new information about the planet and its satellites today. In fact, several of its moons are now believed to have oceans below their icy surfaces. Chapters focus on topics such as Jupiter's orbit and rotation, rings, atmosphere, and moons, as well as on the space missions that have helped us get a closer look at the planet and its moons over the past decades.

  6. General circulation modeling of the thermosphere-ionosphere during a geomagnetic storm

    Science.gov (United States)

    Yiǧit, Erdal; Immel, Thomas; Ridley, Aaron; Frey, Harald U.; Moldwin, Mark

    2016-07-01

    Using a three-dimensional general circulation model (GCM) of the upper atmosphere, we investigate the response of the thermosphere-ionosphere system to the August 2011 major geomagnetic storm. The GCM is driven by measured storm-time input data of the Interplanetary Magnetic Field (IMF), solar activity, and auroral activity. Simulations for quiet steady conditions over the same period are performed as well in order to assess the response of the neutral and plasma parameters to the storm. During the storm, the high-latitude mean ion flows are enhanced by up to ~150%. Overall, the global mean neutral temperature increases by up to 15%, while the maximum thermal response is higher in the winter Southern Hemisphere at high-latitudes than the summer Northern Hemisphere: 40% vs. 20% increase in high-latitude mean temperature, respectively. The global mean Joule heating of the neutral atmosphere increases by more than a factor of three. There are distinct hemispheric differences in the magnitude and morphology of the horizontal ion flows and thermospheric circulation during the different phases of the storm. The thermospheric circulation demonstrates the largest amount of hemispheric differences during the later stages of the storm. Dynamical diagnostics show that advective forcing contributes to hemispheric differences.

  7. Improved short-term variability in the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model

    Science.gov (United States)

    Häusler, K.; Hagan, M. E.; Baumgaertner, A. J. G.; Maute, A.; Lu, G.; Doornbos, E.; Bruinsma, S.; Forbes, J. M.; Gasperini, F.

    2014-08-01

    We report on a new source of tidal variability in the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM). Lower boundary forcing of the TIME-GCM for a simulation of November-December 2009 based on 3-hourly Modern-Era Retrospective Analysis for Research and Application (MERRA) reanalysis data includes day-to-day variations in both diurnal and semidiurnal tides of tropospheric origin. Comparison with TIME-GCM results from a heretofore standard simulation that includes climatological tropospheric tides from the global-scale wave model reveal evidence of the impacts of MERRA forcing throughout the model domain, including measurable tidal variability in the TIME-GCM upper thermosphere. Additional comparisons with measurements made by the Gravity field and steady-state Ocean Circulation Explorer satellite show improved TIME-GCM capability to capture day-to-day variations in thermospheric density for the November-December 2009 period with the new MERRA lower boundary forcing.

  8. Constraining a Martian general circulation model with the MAVEN/IUVS observations in the thermosphere

    Science.gov (United States)

    Moeckel, Chris; Medvedev, Alexander; Nakagawa, Hiromu; Evans, Scott; Kuroda, Takeshi; Hartogh, Paul; Yiğit, Erdal; Jain, Sonal; Lo, Daniel; Schneider, Nicholas M.; Jakosky, Bruce

    2016-10-01

    The recent measurements of the number density of atomic oxygen by Mars Atmosphere and Volatile EvolutioN/ Imaging UltraViolet Spectrograph (MAVEN/IUVS) have been implemented for the first time into a global circulation model to quantify the effect on the Martian thermosphere. The number density has been converted to 1D volume mixing ratio and this profile is compared to the atomic oxygen scenarios based on chemical models. Simulations were performed with the Max Planck Institute Martian General Circulation Model (MPI-MGCM). The simulations closely emulate the conditions at the time of observations. The results are compared to the IUVS-measured CO2 number density and temperature above 130 km to gain knowledge of the processes in the upper atmosphere and further constrain them in MGCMs. The presentation will discuss the role and importance in the thermosphere of the following aspects: (a) impact of the observed atomic oxygen, (b) 27-day solar cycle variations, (c) varying dust load in the lower atmosphere, and (d) gravity waves.

  9. Cooling of the Martian thermosphere by CO$_2$ radiation and gravity waves: An intercomparison study with two general circulation models

    CERN Document Server

    Medvedev, Alexander S; Yiğit, Erdal; Feofilov, Artem G; Forget, François; Hartogh, Paul

    2015-01-01

    Observations show that the lower thermosphere of Mars ($\\sim$100--140 km) is up to 40 K colder than the current general circulation models (GCMs) can reproduce. Possible candidates for physical processes missing in the models are larger abundances of atomic oxygen facilitating stronger CO$_2$ radiative cooling, and thermal effects of gravity waves. Using two state-of-the-art Martian GCMs, the Laboratoire de M\\'et\\'eorologie Dynamique and Max Planck Institute models that self-consistently cover the atmosphere from the surface to the thermosphere, these physical mechanisms are investigated. Simulations demonstrate that the CO$_2$ radiative cooling with a sufficiently large atomic oxygen abundance, and the gravity wave-induced cooling can alone result in up to 40 K colder temperature in the lower thermosphere. Accounting for both mechanisms produce stronger cooling at high latitudes. However, radiative cooling effects peak above the mesopause, while gravity wave cooling rates continuously increase with height. A...

  10. Ionospheric data assimilation with thermosphere-ionosphere-electrodynamics general circulation model and GPS-TEC during geomagnetic storm conditions

    Science.gov (United States)

    Chen, C. H.; Lin, C. H.; Matsuo, T.; Chen, W. H.; Lee, I. T.; Liu, J. Y.; Lin, J. T.; Hsu, C. T.

    2016-06-01

    The main purpose of this paper is to investigate the effects of rapid assimilation-forecast cycling on the performance of ionospheric data assimilation during geomagnetic storm conditions. An ensemble Kalman filter software developed by the National Center for Atmospheric Research (NCAR), called Data Assimilation Research Testbed, is applied to assimilate ground-based GPS total electron content (TEC) observations into a theoretical numerical model of the thermosphere and ionosphere (NCAR thermosphere-ionosphere-electrodynamics general circulation model) during the 26 September 2011 geomagnetic storm period. Effects of various assimilation-forecast cycle lengths: 60, 30, and 10 min on the ionospheric forecast are examined by using the global root-mean-squared observation-minus-forecast (OmF) TEC residuals. Substantial reduction in the global OmF for the 10 min assimilation-forecast cycling suggests that a rapid cycling ionospheric data assimilation system can greatly improve the quality of the model forecast during geomagnetic storm conditions. Furthermore, updating the thermospheric state variables in the coupled thermosphere-ionosphere forecast model in the assimilation step is an important factor in improving the trajectory of model forecasting. The shorter assimilation-forecast cycling (10 min in this paper) helps to restrain unrealistic model error growth during the forecast step due to the imbalance among model state variables resulting from an inadequate state update, which in turn leads to a greater forecast accuracy.

  11. Bayesian calibration of the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM

    Directory of Open Access Journals (Sweden)

    A. D. Richmond

    2009-05-01

    Full Text Available In this paper, we demonstrate a procedure for calibrating a complex computer simulation model having uncertain inputs and internal parameters, with application to the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM. We compare simulated magnetic perturbations with observations at two ground locations for various combinations of calibration parameters. These calibration parameters are: the amplitude of the semidiurnal tidal perturbation in the height of a constant-pressure surface at the TIE-GCM lower boundary, the local time at which this maximises and the minimum night-time electron density. A fully Bayesian approach, that describes correlations in time and in the calibration input space is implemented. A Markov Chain Monte Carlo (MCMC approach leads to potential optimal values for the amplitude and phase (within the limitations of the selected data and calibration parameters but not for the minimum night-time electron density. The procedure can be extended to include additional data types and calibration parameters.

  12. Winds in the Thermosphere

    Science.gov (United States)

    Killeen, T. L.; Burns, A. G.

    2005-12-01

    T. L. Killeen and A. G. Burns Studies of thermospheric dynamics began in the middle 1960s, when King suggested that winds would flow from the hot afternoon sector into the cooler morning region. Later work showed that winds were also driven by the high latitude ion convection pattern and by waves propagating upwards from the lower atmosphere. Ground based Fabry-Perot Interferometers (FPIs) were soon developed that could measure these winds. These interferometers have been deployed successfully both at a variety of ground based locations and in space. Other types of instruments, such as the DE-FPI, WATS and the WINDII instruments, have been deployed successfully in space. The development of thermospheric general circulation models (GCMs) has also greatly increased our understanding of the dynamics of the thermosphere and the way that these dynamics develop as forcing changes. Recent developments include thermosphere-ionosphere GCMs that are coupled with the magnetosphere and improved empirical wind models. In this presentation we summarize the history of thermospheric dynamics. In addition, we discuss current developments with reference to some new, coupled model results that show a number of unexpected features such as strong vertical gradients of horizontal winds in certain conditions and a complex morphology of the dawn convection pattern. Lastly, we suggest some future directions for investigations of the winds in the thermosphere.

  13. Tidal influence on the oxygen and hydroxyl nightglows: Wind Imaging Interferometer observations and thermosphere/ionosphere/mesosphere electrodynamics general circulation model

    Science.gov (United States)

    Zhang, Shengpan P.; Roble, Raymond G.; Shepherd, Gordon G.

    2001-10-01

    Longitudinal zonally averaged Wind Imaging Interferometer (WINDII) (on UARS) night-time oxygen (O(1S)) and hydroxyl (P(3) line in the OH(8, 3) Meinel band) volume emission rates exhibit dramatic spatial and temporal variations. The recently improved thermosphere/ionosphere/mesosphere electrodynamics general circulation model (TIME-GCM) produces simulations for the two airglows through the input of (1, 1) upward propagating diurnal tides. The model simulations show excellent agreement with WINDII observations in both the local time domain and the latitudinal domain between 40°S and 40°N. The influence of diurnal tides on the two airglows in strongest in the tropical region. In the local solar time domain the emission rate and peak altitude at the equator show large tidal perturbations, but they are fairly stable at midlatitude. In the latitudinal domain there is an equatorial trough in the oxygen emission rate which exists regardless of local time and season. The hydroxyl emission rate is more dependent on local time and season. At equinox it has a prominent equatorial maximum which disappears at dawn, whereas at solstice it has a very weak equatorial maximum at dusk, changing soon after midnight to an equatorial minimum. These features of emission rates are also compared to TIME-GCM simulations for meridional wind, temperature, and atomic oxygen density, [O], with and without upward propagating diurnal tides. The results are as follows: (1) The large oscillations of the two nightglows as well the atomic oxygen density in the tropical region are driven by the diurnal propagating tides. In altitude the mesosphere and lower thermosphere is divided into two type of cells, one with meridional winds converging at the equator, higher temperature, and enhanced [O] and airglow emission rates, and the other with meridional winds diverging from the equator, lower temperature, and depleted [O] and airglow emission rates; all these are essentially related to the wavelength

  14. Thermospheric Data Assimilation

    Science.gov (United States)

    2016-05-05

    Thermospheric Data Assimilation 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0058 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dr. Tomoko...unlimited 13. SUPPLEMENTARY NOTES Program Manager: Dr. Julie J Moses, AFOSR, 703-696-9586, Julie.moses@us.af.mil 14. ABSTRACT This project...thermosphere-ionosphere first- principles model. An ensemble data assimilation procedure, constructed with the NCAR Data Assimilation Research Testbed

  15. The EJSM Jupiter-Ganymede Orbiter

    Science.gov (United States)

    Blanc, M.; Lebreton, J.-P.; Stankov, A.; Greeley, R.; Pappalardo, R. T.; Fujimoto, M.

    2008-09-01

    The Europa-Jupiter System Mission (EJSM), currently subject of a joint study by NASA, ESA and JAXA, would combine a fleet of three satellites in order to investigate in depth many questions related to the Jupiter System. These investigations are essential for our understanding of the emergence and evolution of habitable worlds, not only within the Solar System, but also for extrasolar planet investigations. Scientific targets of EJSM focus on Europa and Ganymede as a key pair of Galilean satellites, to address the questions on their habitability, formation, and internal structure, as well as the coupling with the whole Jovian system: Jupiter's atmosphere and interior, magnetosphere and magnetodisk.. In combination with a Jupiter Europa Orbiter (JEO that would be provided by NASA) and a Jupiter Magnetospheric Orbiter (JMO that would be provided by JAXA), ESA is studying a Jupiter Ganymede Orbiter (JGO). The mission scenario includes a launch in 2020 with a transfer time to Jupiter of ~6 years. After the orbit insertion around Jupiter, a first phase (~2 years) will be devoted to Jupiter system and Callisto studies, with multiple flybys of Callisto planned at low altitude (~200 km), followed by a Ganymede orbit insertion and extensive study of Ganymede (~1 year). In depth comparative study of inner (Io and Europe) and outer (Ganymede and Callisto) satellites with combined payload of JEO and JGO will address the question of the geologic relative evolution of the satellites. On JGO, the transport phenomena in the magnetosphere of Jupiter will be studied in combination with JMO, and the Ganymede magnetosphere will be observed in situ. Jupiter atmosphere investigations on JGO will focus on coupling phenomena between troposphere, stratosphere and mesosphere, the stratospheric composition and the question of thermospheric heating.

  16. Near-IR Spectroscopy of the Atmosphere of Jupiter

    Science.gov (United States)

    Baines, R. W.

    1997-01-01

    The Galileo Near Infrared Mapping Spectrometer obtains spectral images in the wavelength range 0.7 to 5.2 um with a special resolving power of approximately 200. This spectral range allows NIMS to sense cloud-reflected solar radiation, thermal emission from the deep atmosphere, and auroral bands from the thermosphere of Jupiter.

  17. Jupiter Eruptions

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers. This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter. Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena. According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  18. Saturn Variable Thermosphere

    CERN Document Server

    Strobel, Darrell F; Mueller-Wodarg, Ingo

    2016-01-01

    Our knowledge of Saturns neutral thermosphere is far superior to that of the other giant planets due to Cassini Ultraviolet Imaging Spectrograph (UVIS) observations of 15 solar occultations and 26 stellar occultations analyzed to date. These measurements yield H2 as the dominant species with an upper limit on the H mole fraction of 5 %. Inferred temperatures near the lower boundary are ~ 150 K, rising to an asymptotic value of ~ 400K at equatorial latitudes and increasing with latitude to polar values in the range of 550-600 K. The latter is consistent with a total estimated auroral power input of ~ 10TW generating Joule and energetic particle heating of ~ 5-6TW that is more than an order of magnitude greater than solar EUV/FUV heating. This auroral heating would be sufficient to solve the energy crisis of Saturns thermospheric heating, if it can be efficiently redistributed to low latitudes. The inferred structure of the thermosphere yields poleward directed pressure gradients on equipotential surfaces consi...

  19. The Jupiter Ganymede Orbiter : An ESA Contribution to the Europa-Jupiter System Mission

    Science.gov (United States)

    Drossart, Pierre; Blanc, M.; Lebreton, J. P.; Pappalardo, R. T.; Greeley, R.; Fujimoto, M.; EJSM/Jupiter Science Definition Team

    2008-09-01

    In the framework of an outer planets mission, under study after the NASA-Juno mission, the Europa-Jupiter System Mission (EJSM) would combine a fleet of up to three satellites in order to investigate in depth many questions related to the Jupiter System. These investigations are essential for our understanding of the emergence and evolution of habitable worlds, not only within the Solar System, but also for extrasolar planets investigations. Scientific targets of EJSM will focus on Europa and Ganymede as a key pair of Galilean satellites, to address the questions on their habitability, formation, and internal structure, as well as the coupling with the whole Jovian system : Jupiter's atmosphere and interior, magnetosphere and magnetodisk. .In combination with a Jupiter Europa Orbiter (JEO likely provided by NASA) and a Jupiter Magnetospheric Orbiter (JMO likely provided by JAXA), ESA is studying a Jupiter Ganymede Orbiter (JGO). The mission scenario includes a direct launch in 2020 with a transfer time to Jupiter of 6 years. After the orbit insertion around Jupiter, a first phase ( 2 years) will be devoted to Jupiter system and Callisto studies, with multiple flybys of Callisto planned at low altitude ( 200 km), followed by a Ganymede orbit insertion and extensive study of Ganymede ( 1 year). In-depth comparative study of inner (Io and Europa) and outer (Ganymede and Callisto) satellites with combined payload of JEO and JGO will address the question of the relative geological evolution of the satellites. On JGO, the transport phenomena in the magnetosphere of Jupiter will be studied in combination with JMO, and the Ganymede magnetosphere will be observed in situ. Jupiter atmosphere investigations on JGO will focus on coupling phenomena between troposphere, stratosphere and mesosphere, the stratospheric composition and the question of thermospheric heating.

  20. Global response of the upper thermospheric winds to large ion drifts in the Jovian ovals

    Science.gov (United States)

    Majeed, T.; Bougher, S. W.; Ridley, A. J.; Waite, J. H.; Gladstone, G. R.; Bell, J. M.

    2016-05-01

    We use our fully coupled 3-D Jupiter Thermosphere General Circulation Model (JTGCM) to quantify processes which are responsible for generating neutral winds in Jupiter's oval thermosphere from 20 µbar to 10-4 nbar self-consistently with the thermal structure and composition. The heat sources in the JTGCM that drive the global circulation of neutral flow are substantial Joule heating produced in the Jovian ovals by imposing high-speed anticorotational ion drifts (~3.5 km s-1) and charged particle heating from auroral processes responsible for bright oval emissions. We find that the zonal flow of neutral winds in the auroral ovals of both hemispheres is primarily driven by competition between accelerations resulting from Coriolis forcing and ion drag processes near the ionospheric peak. However, above the ionospheric peak (<0.01 µbar), the acceleration of neutral flow due to pressure gradients is found to be the most effective parameter impacting zonal winds, competing mainly with acceleration due to advection with minor contributions from curvature and Coriolis forces in the southern oval, while in the northern oval it competes alone with considerable Coriolis forcing. The meridional flow of neutral winds in both ovals in the JTGCM is determined by competition between meridional accelerations due to Coriolis forcing and pressure gradients. We find that meridional flow in the lower thermosphere, near the peak of the auroral ionosphere, is poleward, with peak wind speeds of ~0.6 km s-1 and ~0.1 km s-1 in the southern and northern oval, respectively. The corresponding subsiding flow of neutral motion is ~5 m s-1 in the southern oval, while this flow is rising in the northern oval with reduced speed of ~2 m s-1. We also find that the strength of meridional flow in both auroral ovals is gradually weakened and turned equatorward near 0.08 µbar with wind speeds up to ~250 m s-1 (southern oval) and ~75 m s-1 (northern oval). The corresponding neutral motion in this

  1. The effect of H3+ cooling on jovian thermospheric energy and momentum balance

    Science.gov (United States)

    Ray, L. C.; Achilleos, N. A.; Miller, S.

    2014-12-01

    When the Galileo probe entered Jupiter's equatorial atmosphere, it measured thermospheric exobase temperatures of ~900 K, 700 K higher than what was expected from solar EUV heating. Therefore, there is an 'energy crisis' at Jupiter, in which a large source of equatorial heating is unaccounted for. A prime candidate to explain the high temperatures is the transport of auroral energy equatorwards from high latitudes. However, the combination of strong Coriolis forces from the rapid planetary rotation rate, coupled with ion drag from magnetosphere-ionosphere coupling, results in an 'ion drag fridge' effect (Smith et al., 2007), which acts to transport auroral energy poleward, rather than equatorward. We modify the UCL JASMIN model (Jovian Axisymmetric Simulator with Magnetosphere, Ionosphere, and Neutrals) to include the effects of auroral heating and H3+ cooling. Thus far, auroral heating and H3+ cooling were neglected in dynamical models of the coupled thermosphere-ionosphere-magnetosphere system, in order to focus on the effects of joule heating and ion drag on the jovian thermosphere. We explore how including these heating and cooling terms alters the energy and momentum balance, and subsequently meridional transport through Jupiter's thermosphere.

  2. Resistive Heating in Saturn's Thermosphere

    Science.gov (United States)

    Vriesema, Jess W.; Koskinen, Tommi; Yelle, Roger V.

    2016-10-01

    The thermospheres of the jovian planets are several times hotter than solar heating alone can account for. On Saturn, resistive heating appears sufficient to explain these temperatures in auroral regions, but the particular mechanism(s) responsible for heating the lower latitudes remains unclear. Smith et al. (2005) suggested that electrodynamics of the equatorial region—particularly resistive heating caused by strong electrojet currents—might explain the observed temperatures at low latitudes. Müller-Wodarg et al. (2006) found that their circulation model could reproduce low-latitude temperatures only when they included resistive heating at the poles and applied a uniform, generic heating source globally. Smith et al. (2007) concluded that heating at the poles leads to meridional circulation that cools low latitudes and argued that in-situ heating is required to explain the temperatures at low latitudes.Resistive heating at low latitudes, arising from enhanced current generation driven by thermospheric winds, is a potentially important in-situ heating mechanism. Ion drag caused by low-latitude electrodynamics can modify global circulation and meridional transport of energy. We present an axisymmetric, steady-state formulation of wind-driven electrodynamics to investigate these possibilities throughout Saturn's thermosphere. At present, we assume a dipole magnetic field and neglect any contributions from the magnetosphere. We use ion mixing ratios from the model of Kim et al. (2014) and the observed temperature-pressure profile from Koskinen et al. (2015) to calculate the generalized conductivity tensor as described by Koskinen et al. (2014). Our model solves the coupled equations for charge continuity and Ohm's law with tensor conductivity while enforcing zero current across the boundaries. The resulting partial differential equation is solved for the current density throughout the domain and used to calculate the net resistive heating rate. We demonstrate

  3. rosuvastatin (JUPITER)

    DEFF Research Database (Denmark)

    Nordestgaard, Børge; Ridker, Paul M; MacFadyen, Jean G;

    2009-01-01

    were calculated across a range of end points, timeframes, and subgroups using data from Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), a randomized evaluation of rosuvastatin 20 mg versus placebo conducted among 17 802 apparently healthy men...... infarction, stroke, revascularization, or death, the 5-year NNT within JUPITER was 20 (95% CI, 14 to 34). All subgroups had 5-year NNT values for this end point below 50; as examples, 5-year NNT values were 17 for men and 31 for women, 21 for whites and 19 for nonwhites, 18 for those with body mass index 300...

  4. Atomic oxygen in the Martian thermosphere

    Science.gov (United States)

    Stewart, A. I. F.; Alexander, M. J.; Meier, R. R.; Paxton, L. J.; Bougher, S. W.; Fesen, C. G.

    1992-01-01

    Modern models of thermospheric composition and temperature and of excitation and radiative transfer processes are used to simulate the O I 130-nm emission from Mars measured by the Mariner 9 ultraviolet spectrometer. This paper uses the Mars thermospheric general circulation model calculations (MTGCM) of Bougher et al. (1988) and the Monte Carlo partial frequency redistribution multiple scattering code of Meier and Lee (1982). It is found that the decline in atomic oxygen through the daylight hours predicted by the MTGCM cannot be reconciled with the excess afternoon brightness seen in the data. Oxygen concentrations inferred from the data show a positive gradient through the day, in agreement with the original analysis by Strickland et al. (1973). In addition, the data suggest that the oxygen abundance increases toward high southerly latitudes, in contrast with the MTGCM prediction of high values in the Northern Hemisphere. It appears that solar forcing alone cannot account for the observed characteristics of the Martian thermosphere and that wave and tidal effects may profoundly affect the structure, winds, and composition.

  5. Improved forecasting of thermospheric densities using multi-model ensembles

    Science.gov (United States)

    Elvidge, Sean; Godinez, Humberto C.; Angling, Matthew J.

    2016-07-01

    This paper presents the first known application of multi-model ensembles to the forecasting of the thermosphere. A multi-model ensemble (MME) is a method for combining different, independent models. The main advantage of using an MME is to reduce the effect of model errors and bias, since it is expected that the model errors will, at least partly, cancel. The MME, with its reduced uncertainties, can then be used as the initial conditions in a physics-based thermosphere model for forecasting. This should increase the forecast skill since a reduction in the errors of the initial conditions of a model generally increases model skill. In this paper the Thermosphere-Ionosphere Electrodynamic General Circulation Model (TIE-GCM), the US Naval Research Laboratory Mass Spectrometer and Incoherent Scatter radar Exosphere 2000 (NRLMSISE-00), and Global Ionosphere-Thermosphere Model (GITM) have been used to construct the MME. As well as comparisons between the MMEs and the "standard" runs of the model, the MME densities have been propagated forward in time using the TIE-GCM. It is shown that thermospheric forecasts of up to 6 h, using the MME, have a reduction in the root mean square error of greater than 60 %. The paper also highlights differences in model performance between times of solar minimum and maximum.

  6. Impact of semidiurnal tidal variability during SSWs on the mean state of the ionosphere and thermosphere

    Science.gov (United States)

    Pedatella, N. M.; Richmond, A. D.; Maute, A.; Liu, H.-L.

    2016-08-01

    Observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites reveal a global reduction in the zonal and diurnal mean F region peak electron density (NmF2) during sudden stratosphere warmings (SSWs). The present study investigates the source of the global NmF2 decrease by performing numerical experiments with the National Center for Atmospheric Research (NCAR) thermosphere-ionosphere-electrodynamics general circulation model. The simulations reveal that the NmF2 reduction coincides with a depletion of thermospheric [O]/[N2], indicating that the NmF2 depletion is related to changes in thermospheric composition during SSWs. Numerical experiments further illustrate that the short-term (˜10 day) enhancement of the migrating semidiurnal solar tide (SW2) during SSWs is the source of the variability in thermospheric composition. In particular, the enhancement of the SW2 during SSWs alters the lower thermosphere zonal mean circulation, leading to a reduction in atomic oxygen in the lower thermosphere. The atomic oxygen reduction propagates into the upper thermosphere through molecular diffusion, leading to a decrease in [O]/[N2] throughout the low- to middle-latitude thermosphere. It is anticipated that the effects of the SW2 on the ionosphere and thermosphere investigated herein will be modulated by SSW related enhancements of the migrating semidiurnal lunar tide (M2). The magnitude of the combined impact of the SW2 and M2 on the ionosphere-thermosphere mean state will depend on the relative phasing of the solar and lunar tides. The results demonstrate that in addition to modulating the low-latitude electrodynamics, tidal variability during SSWs can significantly impact the mean state of the ionosphere and thermosphere.

  7. Thermospheric hydrogen response to increases in greenhouse gases

    Science.gov (United States)

    Nossal, S. M.; Qian, L.; Solomon, S. C.; Burns, A. G.; Wang, W.

    2016-04-01

    We investigated thermospheric hydrogen response to increase in greenhouse gases and the dependence of this response to solar activity, using a global mean version of the National Center for Atmospheric Research Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model. We separately doubled carbon dioxide (CO2) and methane (CH4) to study the influence of temperature and changes to source species for hydrogen. Our results indicate that both CO2 cooling and CH4 changes to the source species for hydrogen lead to predicted increases in the upper thermospheric hydrogen density. At 400 km, hydrogen increases ~30% under solar maximum and ~25% under solar minimum responding to doubling of CH4, indicating that hydrogen response to the source variation due to CH4 increase is relatively independent of solar activity. On the other hand, hydrogen response to doubling of CO2 highly depends on solar activity. At 400 km, doubling of CO2 results in an ~7% hydrogen increase at solar maximum, whereas it is ~25% at solar minimum. Consequently, at solar maximum, the predicted ~40% increase in atomic hydrogen in the upper thermosphere is primarily due to the source variation as a result of doubling of CH4, whereas at solar minimum, both cooling due to doubling of CO2 and the source variation due to doubling of CH4 have commensurate effects, resulting in an approximate 50% increase in the modeled upper thermospheric hydrogen.

  8. Forecasting Thermosphere Density: an Overview

    Science.gov (United States)

    Bruinsma, S.

    2015-12-01

    Our knowledge of the thermosphere has improved considerably since 2000 thanks to the availability of high-resolution accelerometer inferred densities. Consequently, precision and shortcomings of thermosphere models are better known. Thermosphere density forecast accuracy is limited by: 1) the accuracy of the thermosphere model 2) the solar and geomagnetic activity forecast 3) the quality of the data assimilation system. The precision of semi-empirical thermosphere models is 10-25%. Solar activity forecasts can be accurate up to 5 days. They become less accurate with time, but some proxies are more forecastable than others. Geomagnetic activity forecasting is more problematic, since in most cases storm events cannot be predicted on any time scale. The forecast accuracy is ultimately bounded by the thermosphere model precision and the (varying) degree to which mainly the solar proxy represents EUV heating of the atmosphere. Both errors can be corrected for by means of near real time (nrt) assimilation of satellite drag data, provided that the data is of high quality. At present, only the classified High Accuracy Satellite Drag Model of the Air Force has that capability operationally, even if other prototype nrt models have been developed. Data assimilation significantly improves density forecasts up to 72-hours out; there is no gain for longer periods due to the short memory of the thermosphere system. Only physical models, e.g. TIMEGCM and CTIPe, can in principle reproduce the dynamic changes in density for example during geomagnetic storms. However, accurate information on atmospheric heating is often missing, or not used. When it is, observed and modeled Traveling Atmospheric Disturbances are very similar. Nonmigrating tides and waves propagating from the lower atmosphere cause longitudinal density variations; sources of geophysical noise for semi-empirical models, they can be predicted qualitatively and sometimes quantitatively with physical models. This

  9. The meteorology of Jupiter

    Science.gov (United States)

    Ingersoll, A. P.

    1976-01-01

    From the point of view of meteorology the most important differences between Jupiter and the earth are related to the fact that Jupiter has an appreciable internal energy source and probably lacks a solid surface. The composition and vertical structure of the Jovian atmosphere is considered along with the composition of Jovian cloud particles, turbulence in Jupiter's atmosphere, data on the horizontal structure and motions of the atmosphere, and questions related to the longevity of Jupiter's clouds. Attention is given to the barotropic characteristics of Jupiter's atmosphere, the radiation balance in the atmosphere of the earth and of Jupiter, and studies of the Great Red Spot.

  10. Analysis of JUPITER experiment in ZPPR-9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1980-09-15

    Information and data from the ZPPR-9 reactor JUPITER experiment are presented concerning a general description of data and methods; criticality; reaction rate ratio and reaction rate distribution; Doppler and sample reactivity worth; sodium void worth; and control rod worth.

  11. Global and Meso-scale Thermospheric Neutral Wind Response to Geomagnetic Storm

    Science.gov (United States)

    Lu, G.; Conde, M.; Doornbos, E.

    2015-12-01

    This paper presents a case study of thermospheric response to the 5 April 2010 geomagnetic storm. The NCAR Thermosphere-Ionosphere-Mesosphere Electrodynamic General Circulation Model (TIMEGCM) is used to investigate thermospheric neutral wind variations during the storm, and the model results are validated through comparison with ground and space based observations. More specifically, we conduct detailed inter-comparison of the winds observed by scanning Doppler imagers (SDI) in Alaska with those derived from the TIMEGCM simulations in order to assess model's ability in reproducing the observed meso-scale wind field. The thermospheric winds obtained from the accelerometers on board the GOCE satellite are also used to validate the simulation results on a global scale. While globally the wind velocity tends to be smaller than ion drift velocity, locally the winds can exceed ion drifts and also blow in the different direction than the ions. We will discuss how the thermospheric winds affect the energetic coupling of the magnetosphere-ionosphere-thermosphere system in terms of Joule heating and field-aligned currents.

  12. Global Response of the Upper Thermosphere to Large Ion Drifts in the Jovian Ovals

    Science.gov (United States)

    Majeed, T.; Bougher, S. W.; Ridley, A. J.; Gladstone, R.; Waite, J. H., Jr.; Bell, J. M.

    2015-12-01

    We use our fully coupled 3-D Jupiter Thermosphere General Circulation Model (JTGCM) to quantify wind processes that are responsible for generating neutral winds in the auroral thermosphere from 20 μbar to 10-4 nbar self-consistently with the thermal structure and compositions. The heat sources in the JTGCM that drive the global circulation of neutral flow are charge particle heating from particle impact of extreme auroral conditions and large amount of Joule heating produced in the Jovian ovals by imposing high speed anticorotational ion drifts up to ~3.5 kms-1. These sources are strongly related to the current system in the equatorial plasma sheet that allows plasma to flow outward from the ionosphere to the magnetosphere in the inner part and return from the magnetosphere to the ionosphere in the outer part. We find that strong pressure gradients are developed in the auroral regions, affecting zonal and meridional winds in addition to local temperature distributions. We also find that the zonal flow of neutral winds in the ovals of both hemispheres is primarily driven by competition between Coriolis forcing and ion drag processes near the ionospheric peak. However, above the ionospheric peak, the acceleration of neutral flow due to pressure gradients is found to be the most effective parameter impacting zonal winds. One of the most important findings of this investigation is that the meridional flow of neutral winds in the Jovian ovals is poleward near the peak of the auroral ionosphere. The strength of this flow is gradually weakened and turned equatorward at the sub-nanobar levels with wind speeds up to ~250 ms-1 in the southern oval and ~75 ms-1 in the northern oval. The corresponding neutral motion in this region is upward with wind speeds up to 4 ms-1 in both ovals. We will discuss the model assumptions, numerical framework and several parameterizations of inputs quantities. Comparisons of key model outputs (e.g. neutral temperatures and wind components

  13. Jupiter System Observer

    Science.gov (United States)

    Senske, Dave; Kwok, Johnny

    2008-01-01

    This slide presentation reviews the proposed mission for the Jupiter System Observer. The presentation also includes overviews of the mission timeline, science goals, and spacecraftspecifications for the satellite.

  14. Voyage to Jupiter.

    Science.gov (United States)

    Morrison, David; Samz, Jane

    This publication illustrates the features of Jupiter and its family of satellites pictured by the Pioneer and the Voyager missions. Chapters included are: (1) "The Jovian System" (describing the history of astronomy); (2) "Pioneers to Jupiter" (outlining the Pioneer Mission); (3) "The Voyager Mission"; (4)…

  15. Northern Belt of Jupiter

    Science.gov (United States)

    2000-01-01

    makes it difficult to see into lower layers at all. The bright regions are generally free of high stratospheric hazes.A small bright spot is visible near the center of each panel. Similar spots have been imaged in turbulent regions by the Galileo spacecraft, and they appear to be very energetic convective storms that move heat from the interior of Jupiter to higher altitudes. These storms are expected to penetrate to great heights, and so it is not surprising to see the storm in the first three images, which probe atmospheric altitudes from the lower to the upper troposphere. What is surprising is the appearance of the spot in the ultraviolet image. Higher resolution, time-lapse images to be captured by Cassini in coming weeks will shed more light on these spectacular features.Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  16. Impacts of SABER CO2-based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

    Science.gov (United States)

    Salinas, Cornelius Csar Jude H.; Chang, Loren C.; Liang, Mao-Chang; Yue, Jia; Russell, James; Mlynczak, Martin

    2016-12-01

    This work estimates global-mean Kzz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics monthly global-mean CO2 profiles and a one-dimensional transport model. It is then specified as a lower boundary into the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Results first show that global-mean CO2 in the mesosphere and lower thermosphere region has annual and semiannual oscillations (AO and SAO) with maxima during solstice seasons along with a primary maximum in boreal summer. Our calculated AO and SAO in global-mean CO2 are then modeled by AO and SAO in global-mean Kzz. It is then shown that our estimated global-mean Kzz is lower in magnitude than the suggested global-mean Kzz from Qian et al. (2009) that can model the observed AO and SAO in the ionosphere/thermosphere (IT) region. However, our estimated global-mean Kzz is similar in magnitude with recent suggestions of global-mean Kzz in models with explicit gravity wave parameterization. Our work therefore concludes that global-mean Kzz from global-mean CO2 profiles cannot model the observed AO and SAO in the IT region because our estimated global-mean Kzz may only be representing eddy diffusion due to gravity wave breaking. The difference between our estimated global-mean Kzz and the global-mean Kzz from Qian et al. (2009) thus represents diffusion and mixing from other nongravity wave sources not directly accounted for in the TIE-GCM lower boundary conditions. These other sources may well be the more dominant lower atmospheric forcing behind the AO and SAO in the IT region.

  17. Thermometric Soots on Hot Jupiters?

    CERN Document Server

    Zahnle, K; Fortney, J J

    2009-01-01

    We use a 1D thermochemical and photochemical kinetics model to predict that the stratospheric chemistry of hot Jupiters should change dramatically as temperature drops from 1200 to 1000 K. At 1200 K methane is too unstable to reach the stratosphere in significant quantities, while thermal decomposition of water is a strong source of OH radicals that oxidize any hydrocarbons that do form to CO and CO$_2$. At 1000 K methane, although very reactive, survives long enough to reach the lower stratosphere, and the greater stability of water coupled with efficient scavenging of OH by H$_2$ raise the effective C/O ratio in the reacting gases above unity. Reduced products such as ethylene, acetylene, and hydrogen cyanide become abundant; such conditions favor polymerization and possible formation of PAHs and soots. Although low temperature is the most important factor favoring hydrocarbons in hot Jupiters, higher rates of vertical mixing and generally lower metallicities also favor organic synthesis. The peculiar prope...

  18. Thermospheric emissions of the early Earth

    Science.gov (United States)

    Bernard, D.; Barthélémy, M.; Gronoff, G.; Ménager, H.; Lilensten, J.

    2012-09-01

    The aim of this work is to examine the thermospheric emission of the Earth over its history. In this first step, we adapt a kinetic transport code developed for different planets of the Solar System to the first atmosphere of the Earth. We take into account the possible changes in the solar emission spectrum to compute the diurnal ionizations, excitations and dissociations. We deduce a thermospheric spectrum averaged over the planet. The effect of solar wind electron precipitation is also considered.

  19. Relative Contributions of Heating and Momentum Forcing to High-Latitude Lower Thermospheric Winds

    Science.gov (United States)

    Kwak, Y. S.; Richmond, A. D.

    2015-12-01

    At high latitudes the thermospheric dynamics are gov­erned by various heat and momentum sources. Recently several modeling studies have been attempt­ed to understand the physical process that control the high-latitude lower thermospheric dynamics. Kwak and Richmond [2007] and Kwak et al. [2007] studied the momentum forcing bal­ance that are mainly responsible for maintaining the high-latitude lower thermospheric wind system by using the National Center for Atmospheric Research Thermo­sphere Ionosphere Electrodynamics General Circulation Model (NCAR TIE-GCM). Kwak and Richmond [2014] analyzed the divergence and vorticity of the high-latitude neutral wind field in the lower thermosphere during the south­ern summertime. In this study, we extend previous works by Kwak and Rich­mond [2007, 2014] and Kwak et al. [2007], which helped to better understand the physical processes maintaining thermospheric dynamics at high latitudes, and here perform a "term analysis of the potential vorticity equation" for the high-latitude neu­tral wind field in the lower thermosphere, on the basis of numerical simulations using the NCAR TIE-GCM. These analyses can provide insight into the relative strength of the heating and the momentum forcing responsible for driving rotational winds at the high-latitude lower thermosphere. The heating is the net heat including the heat transfer by downward molecular and eddy heat conduction, the absorption of solar ultraviolet (UV) and extreme ultraviolet (EUV) ra­diation, auroral heating by particles, Joule dissipation of ionospheric currents, release of chemical energy by the atomic oxygen recombination, and radiative CO2, NO and O infrared emissions. The momentum forcing is associated with the viscous force and the frictional drag force from convecting ions.

  20. JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system

    OpenAIRE

    Grasset, O.; Dougherty, K; Coustenis, A.; Bunce, J; Erd, C.; Titov, D.; Blanc, M.; Coates, A; Drossart, P.; Fletcher, N; Hussmann, H.; Jaumann, R.; N. Krupp; Lebreton, P; O. Prieto-Ballesteros

    2013-01-01

    Past exploration of Jupiter's diverse satellite system has forever changed our understanding of the unique environments to be found around gas giants, both in our solar system and beyond. The detailed investigation of three of Jupiter's Galilean satellites (Ganymede, Europa, and Callisto), which are believed to harbour subsurface water oceans, is central to elucidating the conditions for habitability of icy worlds in planetary systems in general. The study of the Jupiter system and the possib...

  1. Jupiter Environment Tool

    Science.gov (United States)

    Sturm, Erick J.; Monahue, Kenneth M.; Biehl, James P.; Kokorowski, Michael; Ngalande, Cedrick,; Boedeker, Jordan

    2012-01-01

    The Jupiter Environment Tool (JET) is a custom UI plug-in for STK that provides an interface to Jupiter environment models for visualization and analysis. Users can visualize the different magnetic field models of Jupiter through various rendering methods, which are fully integrated within STK s 3D Window. This allows users to take snapshots and make animations of their scenarios with magnetic field visualizations. Analytical data can be accessed in the form of custom vectors. Given these custom vectors, users have access to magnetic field data in custom reports, graphs, access constraints, coverage analysis, and anywhere else vectors are used within STK.

  2. Moons around Jupiter

    Science.gov (United States)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet; the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere. Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles); Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon; Ganymede is larger than the planet Mercury.

  3. Coupled rotational dynamics of Saturn's thermosphere and magnetosphere: a thermospheric modelling study

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2008-05-01

    Full Text Available We use a numerical model of Saturn's thermosphere to investigate the flow of angular momentum from the atmosphere to the magnetosphere. The thermosphere model is driven by Joule heating and ion drag calculated from a simple model of the magnetospheric plasma flows and a fixed model of the ionospheric conductivity. We describe an initial study in which our plasma flow model is fixed and find that this leads to several inconsistencies in our results. We thus describe an improved model in which the plasma flows are allowed to vary in response to the structure of the thermospheric winds. Using this improved model we are able to analyse in detail the mechanism by which angular momentum extracted from the thermosphere by the magnetosphere is replaced by transport from the lower atmosphere. Previously, this transport was believed to be dominated by vertical transport due to eddy viscosity. Our results suggest that transport within the upper atmosphere by meridional winds is a much more important mechanism. As a consequence of this, we find that the rotational structures of the thermosphere and magnetosphere are related in a more complex way than the eddy viscosity model implies. Rather than the thermosphere behaving as a passive component of the system, the thermosphere-magnetosphere interaction is shown to be a two-way process in which rotational structures develop mutually. As an example of this, we are able to show that thermospheric dynamics offer an explanation of the small degree of super-corotation that has been observed in the inner magnetosphere. These results call into question the usefulness of the effective Pedersen conductivity as a parameterisation of the neutral atmosphere. We suggest that a two-parameter model employing the true Pedersen conductivity and the true thermospheric rotation velocity may be a more accurate representation of the thermospheric behaviour.

  4. Jupiter Laser Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Jupiter Laser Facility is an institutional user facility in the Physical and Life Sciences Directorate at LLNL. The facility is designed to provide a high degree...

  5. Inferno on Jupiter

    Institute of Scientific and Technical Information of China (English)

    诸葛勤

    1994-01-01

    The initial sketchy reports began filtering into the U. S. by E-maillate Saturday afternoon. First a Spanish observatory announced that it hadspotted a plume of gas billowing up from the edge of Jupiter. Then a

  6. No Detectable H3+ Emission from the Atmospheres of Hot Jupiters

    CERN Document Server

    Shkolnik, E; Moskovitz, N; Shkolnik, Evgenya; Gaidos, Eric; Moskovitz, Nick

    2006-01-01

    H$_3^+$ emission is the dominant cooling mechanism in Jupiter's thermosphere and a useful probe of temperature and ion densities. The H$_3^+$ ion is predicted to form in the thermospheres of close-in `hot Jupiters' where its emission would be a significant factor in the thermal energy budget, affecting temperature and the rate of hydrogen escape from the exosphere. Hot Jupiters are predicted to have up to 10$^5$ times Jupiter's H$_3^+$ emission because they experience extreme stellar irradiation and enhanced interactions may occur between the planetary magnetosphere and the stellar wind. Direct (but unresolved) detection of an extrasolar planet, or the establishment of useful upper limits, may be possible because a small but significant fraction of the total energy received by the planet is re-radiated in a few narrow lines of H$_3^+$ within which the flux from the star is limited. We present the observing strategy and results of our search for emission from the Q(1,0) transition of H$_3^+$ (3.953~$\\mu$m) fro...

  7. First simultaneous measurements of thermospheric winds and zonal ion drifts from the Jicamarca Radio Observatory

    Science.gov (United States)

    Meriwether, John; Baker, Brooke; Twork, Greg; Chau, Jorge; Veliz, Oskar; Woodman, Ronald; Hedden, Russell; Hysell, David

    The first simultaneous observations of thermospheric winds and zonal ion drifts have been ob-tained at the Jicamarca Radio Observatory using a new Fabry-Perot interferometer observatory installed on a mountain ridge overlooking the valley where the JRO radar is located. The re-sults show that the neutral winds and ion drifts generally have the same speed and temporal variation characteristics. These results illustrate the simultaneous detection of the midnight temperature maximum as well. The paper will also describe efforts to obtain common volume measurements of thermospheric winds and temperatures utilizing the FPI Arequipa observatory which is located 4 degrees south of the geomagnetic equator.

  8. Jupiter's Dynamic Magnetosphere

    Science.gov (United States)

    Vogt, M. F.; Bunce, E. J.; Kronberg, E. A.; Jackman, C. M.

    2014-12-01

    Jupiter's magnetosphere is a highly dynamic environment. Hundreds of reconnection events have been identified in Jupiter's magnetotail through analysis of magnetic field and particle measurements collected by the Galileo spacecraft. Quasi-periodic behavior, suggestive of reconnection, has been intermittently observed on a ~2-3 day time scale in several data sets, including magnetic field dipolarizations, flow bursts, auroral polar dawn spots, and the hectometric radio emission. In this paper we review the present state of knowledge of Jovian magnetospheric dynamics. Throughout the discussion, we highlight similarities and differences to Saturn's magnetosphere. For example, recent analysis of plasmoid signatures at both Jupiter and Saturn has established the role of tail reconnection in the overall mass and flux transport in the outer planet magnetospheres. The results for both Jupiter and Saturn suggest that the observed mass loss rate due to tail reconnection and plasmoid release is insufficient to account for the mass input rate from the moons Io and Enceladus, respectively. We also present new analysis in which we use the Michigan mSWiM propagated solar wind MHD model to estimate the solar wind conditions upstream of Jupiter. This information allows us to determine whether reconnection events occur preferentially during certain solar wind conditions, or whether there is evidence that the solar wind modulates the quasi-periodicity seen in the field dipolarizations and flow bursts.

  9. Winds and composition changes in the thermosphere using the transfer function model

    Science.gov (United States)

    Mayr, H. G.; Harris, I.; Herrero, F. A.; Varosi, F.

    1997-04-01

    Different theoretical formulations are used to describe the thermosphere, ranging from fully analytical, linear models based, in the case of gravity waves, on the work of C. O. Hines, to fully numerical, thermospheric general circulation models (TGCMs), which account for non-linear processes and coupling with the ionospheric plasma. The semi-analytical Transfer Function Model (TFM) describes perturbations in the wind field, temperature and composition, accounting in self-consistent form for the momentum transfer between species. The perturbations are driven by external energy and momentum sources associated with absorbed solar radiation and magnetospheric processes. Compared with TGCMs, the TFM is simplified mainly by its linear approximation. But the model is not limited in its spatial and temporal resolutions, and it describes acoustic gravity waves that are generated in the thermosphere and partially propagate through the lower atmosphere. Moreover, the model is semi-analytical, which helps in delineating and understanding the dynamical characteristics. Using expansions in terms of vector spherical harmonics and Fourier transformation, the transfer function of the atmosphere is obtained through numerical height integration, which is time consuming computationally but needs to be done only once. Once the transfer function is constructed, the thermospheric response is obtained virtually instantaneously, thus providing an efficient tool for numerical simulation and experimentation. After a review of the TFM, results are discussed, which describe a number of thermospheric phenomena covering a wide range of spatial and temporal scales. These include magnetic storm effects as well as gravity waves propagating in the thermosphere, which are partially reflected from the Earth's surface and ducted through the lower atmosphere.

  10. Marshall Engineering Thermosphere Model, Version MET-2007

    Science.gov (United States)

    Suggs, R. J.; Suggs, R. M.

    2017-01-01

    The region of the Earth's atmosphere between about 90 and 500 km altitude is known as the thermosphere, while the region above about 500 km is known as the exosphere. For space vehicle operations, the neutral atmosphere in these regions is significant. Even at its low density, it produces torques and drags on vehicles and affects orbital lifetimes. The thermosphere density above 100 km altitude also modulates the flux of trapped radiation and orbital debris. Atomic oxygen at orbital altitudes is important because it can erode and chemically change exposed vehicle surfaces.

  11. Jupiter - friend or foe?

    Science.gov (United States)

    Horner, J.; Jones, B. W.

    2007-08-01

    Throughout both popular science and academia, there is a pervasive belief that Jupiter has acted as a celestial shield, reducing the impact rate on the Earth, and making the planet a significantly more conducive site for the evolution and survival of life. This old idea has, however, undergone little detailed scrutiny. In the first of a series of studies aimed at a better understanding of this idea, we examine the variation in the impact rate on the Earth which results from bodies moving inwards from the Edgeworth- Kuiper belt as a function of the mass of a giant planet in Jupiter's orbit. The results are not entirely what would be expected under the "Jupiter Shield" paradigm.

  12. Sharpening Up Jupiter

    Science.gov (United States)

    2008-10-01

    New image-correction technique delivers sharpest whole-planet ground-based picture ever A record two-hour observation of Jupiter using a superior technique to remove atmospheric blur has produced the sharpest whole-planet picture ever taken from the ground. The series of 265 snapshots obtained with the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO's Very Large Telescope (VLT) reveal changes in Jupiter's smog-like haze, probably in response to a planet-wide upheaval more than a year ago. Sharpening Up Jupiter ESO PR Photo 33/08 Sharpening Up Jupiter Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques [1]. "This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae," says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. "While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations." MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble's 96-minute orbit. Using MAD, ESO astronomer Paola Amico

  13. Understanding Jupiter's Interior

    CERN Document Server

    Militzer, Burkhard; Wahl, Sean M; Hubbard, William

    2016-01-01

    This article provides an overview of how models of giant planet interiors are constructed. We review measurements from past space missions that provide constraints for the interior structure of Jupiter. We discuss typical three-layer interior models that consist of a dense central core and an inner metallic and an outer molecular hydrogen-helium layer. These models rely heavily on experiments, analytical theory, and first-principle computer simulations of hydrogen and helium to understand their behavior up to the extreme pressures ~10 Mbar and temperatures ~10,000 K. We review the various equations of state used in Jupiter models and compare them with shock wave experiments. We discuss the possibility of helium rain, core erosion and double diffusive convection may have important consequences for the structure and evolution of giant planets. In July 2016 the Juno spacecraft entered orbit around Jupiter, promising high-precision measurements of the gravitational field that will allow us to test our understandi...

  14. Jupiter's Rings: Sharpest View

    Science.gov (United States)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  15. A Preliminary Jupiter Model

    CERN Document Server

    Hubbard, W B

    2016-01-01

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses, and a hydrogen-helium-rich envelope with...

  16. A Preliminary Jupiter Model

    Science.gov (United States)

    Hubbard, W. B.; Militzer, B.

    2016-03-01

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen-helium-rich envelope with approximately three times solar metallicity.

  17. Tracking the energy input form the magnetosphere to the ionosphere-thermosphere system

    Science.gov (United States)

    Zesta, E.; Connor, H.; Shi, Y.; Raeder, J.; Fedrizzi, M.; Fuller-Rowell, T. J.; Codrescu, M.

    2014-12-01

    latitudes within the same spatial region before the heating moves equatorward. We look for general trends of the correlation between Poynting flux and thermospheric heating with an initial superposed epoch analysis study.

  18. Polarizing Michelson interferometer for measuring thermospheric winds

    Energy Technology Data Exchange (ETDEWEB)

    Bird, J.C.

    1991-01-01

    The Polarizing Atmospheric Michelson Interferometer, PAMI, a new version of the Wide Angle Michelson Interferometer, is used to measure winds in the termosphere. In the polarizing instrument, the optical path difference is changed simply by rotating a polarizing filter external to the interferometer. This allows a very simple scanning mechanism. PAMI is similar to other instruments such as WAMDII that measure thermospheric winds and temperatures, retaining the benefits of high light throughput, while offering advantages including lower cost, simplicity, and portability. The instrument is highly sensitive and thus is designed to be used for field measurements at locations far from city lights. Results are shown from the AIDA observation campaign in Puerto Rico where coordinated observations were made by PAMI along with other optical and radio measurements during April and May 1989. Intensities of the green line layer at 95 km were compared to those observed by several other instruments. For example, MORTI (Mesopause Oxygen Rotational Temperature Imager), a colocated instrument which was looking at the 94 km 867.6 nm molecular oxygen emission. MORTI and PAMI emission rates were found to show the same trends. On the brightest night recorded during April, the zenith emission rate reached over 400 Rayleighs; emission enhancements were sometimes related to auroral events. During the observing period of April 4 to April 11, 1989, most of the observations of the 94 km airglow were after midnight where the winds were found to be generally towards the north east at about 50 to 100 m/s. During auroral activity this wind vector always turned counterclockwise, towards the west. During the nights of May 2 and May 6 these wind vectors follow a wave-like variation in magnitude and direction. It is concluded that auroral activity changes the global circulation in a way that sometimes transports increased amounts of oxygen atoms over Arecibo.

  19. Equinoctial transitions in the ionosphere and thermosphere

    Directory of Open Access Journals (Sweden)

    A. V. Mikhailov

    Full Text Available Equinoctial summer/winter transitions in the parameters of the F2-region are analyzed using ground-based ionosonde and incoherent scatter observations. Average transition from one type of diurnal NmF2 variation to another takes 20–25 days, but cases of very fast (6–10 days transitions are observed as well. Strong day-time NmF2 deviations of both signs from the monthly median, not related to geomagnetic activity, are revealed for the transition periods. Both longitudinal and latitudinal variations take place for the amplitude of such quiet time NmF2 deviations. The summer-type diurnal NmF2 variation during the transition period is characterized by decreased atomic oxygen concentration [O] and a small equatorward thermospheric wind compared to winter-type days with strong poleward wind and increased [O]. Molecular N2 and O2 concentrations remain practically unchanged in such day-to-day transitions. The main cause of the F2-layer variations during the transition periods is the change of atomic oxygen abundance in the thermosphere related to changes of global thermospheric circulation. A possible relationship with an equinoctial transition of atomic oxygen at the E-region heights is discussed.

    Key words. Atmospheric composition and structure (thermosphere – composition and chemistry – Ionosphere (ionosphere- atmosphere interactions; ionospheric disturbances

  20. Gravity wave effects in the thermosphere during sudden stratospheric warmings and vertical coupling between the lower and upper atmosphere

    Science.gov (United States)

    Yiǧit, Erdal; Medvedev, Alexander S.

    2016-07-01

    Gravity waves are primarily generated in the lower atmosphere, propagate upward, and have profound effects not only in the middle atmosphere but also at much higher altitudes. However, their effects in the upper atmosphere beyond the turbopause ( 105 km) have not been sufficiently studied. Using a general circulating model extending from the lower atmosphere to upper thermosphere and incorporating a whole atmosphere nonlinear parameterization of small-scale GWs developed by Yiǧit et al. (2008)}, we demonstrate that not only GWs penetrate into the thermosphere above the turbopause but also produce substantial dynamical and thermal effects that are comparable to ion drag and Joule heating. During sudden stratospheric warmings, GW propagation in the thermosphere is enhanced by more than a factor of three (Yiǧit and Medvedev, 2012)}, producing appreciable body forcing of up to 600 m s^{-1} day^{-1} around 250-300 km. The resultant impact on the variability of the thermospheric circulation can exceed ± 50% depending on the phase of the sudden warming (Yiǧit et al., 2014)}. References: Yiǧit, E., and A. S. Medvedev (2012), Gravity waves in the thermosphere during a sudden stratospheric warming, Geophys. Res. Lett., 39, L21101, doi:10.1029/2012GL053812. Yiǧit, E., A. D. Aylward, and A. S. Medvedev (2008), Parameterization of the effects of vertically propagating gravity waves for thermosphere general circulation models: Sensitivity study, J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135. Yiǧit, E., A. S. Medvedev, S. L. England, and T. J. Immel (2014), Simulated vari- ability of the high-latitude thermosphere induced by small-scale gravity waves during a sudden stratospheric warming, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019283.

  1. Jupiter's Big Bang.

    Science.gov (United States)

    McDonald, Kim A.

    1994-01-01

    Collision of a comet with Jupiter beginning July 16, 1994 will be observed by astronomers worldwide, with computerized information relayed to a center at the University of Maryland, financed by the National Aeronautics and Space Administration and National Science Foundation. Geologists and paleontologists also hope to learn more about earth's…

  2. Radiation belts of jupiter.

    Science.gov (United States)

    Stansberry, K G; White, R S

    1973-12-07

    Predictions of Jupiter's electron and proton radiation belts are based mainly on decimeter observations of 1966 and 1968. Extensive calculations modeling radial diffusion of particles inward from the solar wind and electron synchrotron radiation are used to relate the predictions and observations.

  3. A Transiting Jupiter Analog

    CERN Document Server

    Kipping, David M; Henze, Chris; Teachey, Alex; Isaacson, Howard T; Petigura, Erik A; Marcy, Geoffrey W; Buchhave, Lars A; Chen, Jingjing; Bryson, Steve T; Sandford, Emily

    2016-01-01

    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of $(0.91\\pm0.02)$ $R_{\\mathrm{Jup}}$, a low orbital eccentricity ($0.06_{-0.04}^{+0.10}$) and an equilibrium temperature of $(131\\pm3)$ K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric ...

  4. Polar heating in Saturn's thermosphere

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2005-10-01

    Full Text Available A 3-D numerical global circulation model of the Kronian thermosphere has been used to investigate the influence of polar heating. The distributions of temperature and winds resulting from a general heat source in the polar regions are described. We show that both the total energy input and its vertical distribution are important to the resulting thermal structure. We find that the form of the topside heating profile is particularly important in determining exospheric temperatures. We compare our results to exospheric temperatures from Voyager occultation measurements (Smith et al., 1983; Festou and Atreya, 1982 and auroral H3+ temperatures from ground-based spectroscopic observations (e.g. Miller et al., 2000. We find that a polar heat source is consistent with both the Smith et al. determination of T~400 K at ~30° N and auroral temperatures. The required heat source is also consistent with recent estimates of the Joule heating rate at Saturn (Cowley et al., 2004. However, our results show that a polar heat source can probably not explain the Festou and Atreya determination of T~800 K at ~4° N and the auroral temperatures simultaneously.

    Keywords. Ionosphere (Planetary ionosphere – Magnetospherica physics (Planetary magnetospheres – Meterology and atmospheric dynamics (Thermospheric dynamics

  5. Substorm-related thermospheric density and wind disturbances derived from CHAMP observations

    Directory of Open Access Journals (Sweden)

    P. Ritter

    2010-06-01

    Full Text Available The input of energy and momentum from the magnetosphere is most efficiently coupled into the high latitude ionosphere-thermosphere. The phenomenon we are focusing on here is the magnetospheric substorm. This paper presents substorm related observations of the thermosphere derived from the CHAMP satellite. With its sensitive accelerometer the satellite can measure the air density and zonal winds. Based on a large number of substorm events the average high and low latitude thermospheric response to substorm onsets was deduced. During magnetic substorms the thermospheric density is enhanced first at high latitudes. Then the disturbance travels at an average speed of 650 m/s to lower latitudes, and 3–4 h later the bulge reaches the equator on the night side. Under the influence of the Coriolis force the travelling atmospheric disturbance (TAD is deflected westward. In accordance with present-day atmospheric models the disturbance zonal wind velocities during substorms are close to zero near the equator before midnight and attain moderate westward velocities after midnight. In general, the wind system is only weakly perturbed (Δvy<20 m/s by substorms.

  6. Atomic oxygen distributions in the Venus thermosphere: Comparisons between Venus Express observations and global model simulations

    Science.gov (United States)

    Brecht, A. S.; Bougher, S. W.; Gérard, J.-C.; Soret, L.

    2012-02-01

    Nightglow emissions provide insight into the global thermospheric circulation, specifically in the transition region (˜70-120 km). The O 2 IR nightglow statistical map created from Venus Express (VEx) Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) observations has been used to deduce a three-dimensional atomic oxygen density map. In this study, the National Center of Atmospheric Research (NCAR) Venus Thermospheric General Circulation Model (VTGCM) is utilized to provide a self-consistent global view of the atomic oxygen density distribution. More specifically, the VTGCM reproduces a 2D nightside atomic oxygen density map and vertical profiles across the nightside, which are compared to the VEx atomic oxygen density map. Both the simulated map and vertical profiles are in close agreement with VEx observations within a ˜30° contour of the anti-solar point. The quality of agreement decreases past ˜30°. This discrepancy implies the employment of Rayleigh friction within the VTGCM may be an over-simplification for representing wave drag effects on the local time variation of global winds. Nevertheless, the simulated atomic oxygen vertical profiles are comparable with the VEx profiles above 90 km, which is consistent with similar O 2 ( 1Δ) IR nightglow intensities. The VTGCM simulations demonstrate the importance of low altitude trace species as a loss for atomic oxygen below 95 km. The agreement between simulations and observations provides confidence in the validity of the simulated mean global thermospheric circulation pattern in the lower thermosphere.

  7. Middle atmosphere dynamical sources of the semiannual oscillation in the thermosphere and ionosphere

    Science.gov (United States)

    Jones, M.; Emmert, J. T.; Drob, D. P.; Siskind, D. E.

    2017-01-01

    The strong global semiannual oscillation (SAO) in thermospheric density has been observed for five decades, but definitive knowledge of its source has been elusive. We use the National Center of Atmospheric Research thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) to study how middle atmospheric dynamics generate the SAO in the thermosphere-ionosphere (T-I). The "standard" TIME-GCM simulates, from first principles, SAOs in thermospheric mass density and ionospheric total electron content that agree well with observed climatological variations. Diagnosis of the globally averaged continuity equation for atomic oxygen ([O]) shows that the T-I SAO originates in the upper mesosphere, where an SAO in [O] is forced by nonlinear, resolved-scale variations in the advective, net tidal, and diffusive transport of O. Contrary to earlier hypotheses, TIME-GCM simulations demonstrate that intra-annually varying eddy diffusion by breaking gravity waves may not be the primary driver of the T-I SAO: A pronounced SAO is produced without parameterized gravity waves.

  8. JUICE: A European Mission to Jupiter and its Icy Moons

    Science.gov (United States)

    Grasset, Olivier; Witasse, Olivier; Barabash, Stas; Brandt, Pontus; Bruzzone, Lorenzo; Bunce, Emma; Cecconi, Baptiste; Cavalié, Thibault; Cimo, Giuseppe; Coustenis, Athena; Cremonese, Gabriele; Dougherty, Michele; Fletcher, Leigh N.; Gladstone, Randy; Gurvits, Leonid; Hartogh, Paul; Hoffmann, Holger; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Kasaba, Yasumasa; Kaspi, Yohai; Krupp, Norbert; Langevin, Yves; Mueller-Wodarg, Ingo; Palumbo, Pasquale; Piccioni, Giuseppe; Plaut, Jeffrey; Poulet, Francois; Roatsch, Thomas; Retherford, Kurt D.; Rothkaehl, Hanna; Stevenson, David J.; Tosi, Federico; Van Hoolst, Tim; Wahlund, Jan-Erik; Wurz, Peter; Altobelli, Nicolas; Accomazzo, A.; Boutonnet, Arnaud; Erd, Christian; Vallat, Claire

    2016-10-01

    JUICE - JUpiter ICy moons Explorer - is the first large mission in the ESA Cosmic Vision programme [1]. The implementation phase started in July 2015. JUICE will arrive at Jupiter in October 2029, and will spend 3 years characterizing the Jovian system, the planet itself, its giant magnetosphere, and the giant icy moons: Ganymede, Callisto and Europa. JUICE will then orbit Ganymede.The first goal of JUICE is to explore the habitable zone around Jupiter [2]. Ganymede is a high-priority target because it provides a unique laboratory for analyzing the nature, evolution and habitability of icy worlds, including the characteristics of subsurface oceans, and because it possesses unique magnetic fields and plasma interactions with the environment. On Europa, the focus will be on recently active zones, where the composition, surface and subsurface features (including putative water reservoirs) will be characterized. Callisto will be explored as a witness of the early Solar System.JUICE will also explore the Jupiter system as an archetype of gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere and ionosphere. JUICE will investigate the 3D properties of the magnetodisc, and study the coupling processes within the magnetosphere, ionosphere and thermosphere. The mission also focuses on characterizing the processes that influence surface and space environments of the moons.The payload consists of 10 instruments plus a ground-based experiment (PRIDE) to better constrain the S/C position. A remote sensing package includes imaging (JANUS) and spectral-imaging capabilities from UV to sub-mm wavelengths (UVS, MAJIS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the moons, and a radio science experiment (3GM) to probe the atmospheres and to determine the gravity fields. The in situ package comprises a suite to study plasma and

  9. Polarized Light from Jupiter

    Science.gov (United States)

    2001-01-01

    These images taken through the wide angle camera near closest approach in the deep near-infrared methane band, combined with filters which sense electromagnetic radiation of orthogonal polarization, show that the light from the poles is polarized. That is, the poles appear bright in one image, and dark in the other. Polarized light is most readily scattered by aerosols. These images indicate that the aerosol particles at Jupiter's poles are small and likely consist of aggregates of even smaller particles, whereas the particles at the equator and covering the Great Red Spot are larger. Images like these will allow scientists to ascertain the distribution, size and shape of aerosols, and consequently, the distribution of heat, in Jupiter's atmosphere.

  10. Jupiter's Water Worlds

    Science.gov (United States)

    Pappalardo, R. T.

    2004-01-01

    When the twin Voyager spacecraft cruised past Jupiter in 1979, they did more than rewrite the textbooks on the giant planet. Their cameras also unveiled the astounding diversity of the four planet-size moons of ice and stone known as the Galilean satellites. The Voyagers revealed the cratered countenance of Callisto, the valleys and ridges of Ganymede, the cracked face of Europa, and the spewing volcanoes of Io. But it would take a spacecraft named for Italian scientist Galileo, who discovered the moons in 1610, to reveal the true complexity of these worlds and to begin to divulge their interior secrets. Incredibly, the Galileo data strongly suggest that Jupiter's three large icy moons (all but rocky Io) hide interior oceans.

  11. Thermospheric Nitric Oxide Response to Shock-led Storms.

    Science.gov (United States)

    Knipp, D J; Pette, D V; Kilcommons, L M; Isaacs, T L; Cruz, A A; Mlynczak, M G; Hunt, L A; Lin, C Y

    2017-02-01

    We present a multi-year superposed epoch study of the Sounding of the Atmosphere using Broadband Emission Radiometry nitric oxide (NO) emission data. NO is a trace constituent in the thermosphere that acts as cooling agent via infrared (IR) emissions. The NO cooling competes with storm time thermospheric heating resulting in a thermostat effect. Our study of nearly 200 events reveals that shock-led interplanetary coronal mass ejections (ICMEs) are prone to early and excessive thermospheric NO production and IR emissions. Excess NO emissions can arrest thermospheric expansion by cooling the thermosphere during intense storms. The strongest events curtail the interval of neutral density increase and produce a phenomenon known as thermospheric 'overcooling'. We use Defense Meteorological Satellite Program particle precipitation data to show that interplanetary shocks and their ICME drivers can more than double the fluxes of precipitating particles that are known to trigger the production of thermospheric NO. Coincident increases in Joule heating likely amplify the effect. In turn, NO emissions more than double. We discuss the roles and features of shock/sheath structures that allow the thermosphere to temper the effects of extreme storm time energy input and explore the implication these structures may have on mesospheric NO. Shock-driven thermospheric NO IR cooling likely plays an important role in satellite drag forecasting challenges during extreme events.

  12. A PRELIMINARY JUPITER MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, W. B. [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Militzer, B. [Department of Earth and Planetary Science, Department of Astronomy, University of California, Berkeley, CA 94720 (United States)

    2016-03-20

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen–helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen–helium-rich envelope with approximately three times solar metallicity.

  13. Jupiter's Grand Attack

    Science.gov (United States)

    Batygin, Konstantin

    2017-06-01

    The statistics of extrasolar planetary systems indicate that the default mode of planetary formation generates planets with orbital periods shorter than 100 days, and masses substantially exceeding that of the Earth. When viewed in this context, the Solar System, which contains no planets interior to Mercury's 88-day orbit, is unusual. Extra-solar planetary detection surveys also suggest that planets with masses and periods broadly similar to Jupiter's are somewhat uncommon, with occurrence fraction of less than ~ 10%. In this talk, I will present calculations which show that a popular formation scenario for Jupiter and Saturn, in which Jupiter migrates inward from a > 5AU to a ˜ 1.5 AU and then reverses direction, can explain the low overall mass of the Solar System's terrestrial planets, as well as the absence of planets with a 10 - 100 km planetesimals into low- order mean-motion resonances, shepherding of order 10 Earth masses of this material into the a ˜ 1 AU region while exciting substantial orbital eccentricity (e ˜ 0.2 - 0.4). We argue that under these conditions, a collisional cascade will ensue, generating a planetesimal disk that would have flushed any preexisting short-period super-Earth-like planets into the Sun. In this scenario, the Solar System's terrestrial planets formed from gas-starved mass-depleted debris that remained after the primary period of dynamical evolution.

  14. Voyager picture of Jupiter

    Science.gov (United States)

    1998-01-01

    NASA's Voyager 1 took this picture of the planet Jupiter on Saturday, Jan. 6, the first in its three-month-long, close-up investigation of the largest planet. The spacecraft, flying toward a March 5 closest approach, was 35.8 million miles (57.6 million kilometers) from Jupiter and 371.7 million miles (598.2 million kilometers) from Earth when the picture was taken. As the Voyager cameras begin their meteorological surveillance of Jupiter, they reveal a dynamic atmosphere with more convective structure than had previously been thought. While the smallest atmospheric features seen in this picture are still as large as 600 miles (1,000 kilometers) across, Voyager will be able to detect individual storm systems as small as 3 miles (5 kilometers) at closest approach. The Great Red Spot can be seen near the limb at the far right. Most of the other features are too small to be seen in terrestrial telescopes. This picture was transmitted to the Jet Propulsion Laboratory through the Deep Space Network's tracking station at Madrid, Spain. The Voyager Project is managed for NASA by Caltech's Jet Propulsion Laboratory.

  15. Voyager 2 Jupiter Eruption Movie

    Science.gov (United States)

    2000-01-01

    This movie records an eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over avery short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as 'spaghetti bowls'.As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  16. Gravity wave penetration into the thermosphere: sensitivity to solar cycle variations and mean winds

    Directory of Open Access Journals (Sweden)

    D. C. Fritts

    2008-12-01

    Full Text Available We previously considered various aspects of gravity wave penetration and effects at mesospheric and thermospheric altitudes, including propagation, viscous effects on wave structure, characteristics, and damping, local body forcing, responses to solar cycle temperature variations, and filtering by mean winds. Several of these efforts focused on gravity waves arising from deep convection or in situ body forcing accompanying wave dissipation. Here we generalize these results to a broad range of gravity wave phase speeds, spatial scales, and intrinsic frequencies in order to address all of the major gravity wave sources in the lower atmosphere potentially impacting the thermosphere. We show how penetration altitudes depend on gravity wave phase speed, horizontal and vertical wavelengths, and observed frequencies for a range of thermospheric temperatures spanning realistic solar conditions and winds spanning reasonable mean and tidal amplitudes. Our results emphasize that independent of gravity wave source, thermospheric temperature, and filtering conditions, those gravity waves that penetrate to the highest altitudes have increasing vertical wavelengths and decreasing intrinsic frequencies with increasing altitude. The spatial scales at the highest altitudes at which gravity wave perturbations are observed are inevitably horizontal wavelengths of ~150 to 1000 km and vertical wavelengths of ~150 to 500 km or more, with the larger horizontal scales only becoming important for the stronger Doppler-shifting conditions. Observed and intrinsic periods are typically ~10 to 60 min and ~10 to 30 min, respectively, with the intrinsic periods shorter at the highest altitudes because of preferential penetration of GWs that are up-shifted in frequency by thermospheric winds.

  17. Estimation of energy budget of ionosphere-thermosphere system during two CIR-HSS events: observations and modeling

    Science.gov (United States)

    Verkhoglyadova, Olga; Meng, Xing; Mannucci, Anthony J.; Tsurutani, Bruce T.; Hunt, Linda A.; Mlynczak, Martin G.; Hajra, Rajkumar; Emery, Barbara A.

    2016-04-01

    We analyze the energy budget of the ionosphere-thermosphere (IT) system during two High-Speed Streams (HSSs) on 22-31 January, 2007 (in the descending phase of solar cycle 23) and 25 April-2 May, 2011 (in the ascending phase of solar cycle 24) to understand typical features, similarities, and differences in magnetosphere-ionosphere-thermosphere (IT) coupling during HSS geomagnetic activity. We focus on the solar wind energy input into the magnetosphere (by using coupling functions) and energy partitioning within the IT system during these intervals. The Joule heating is estimated empirically. Hemispheric power is estimated based on satellite measurements. We utilize observations from TIMED/SABER (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) to estimate nitric oxide (NO) and carbon dioxide (CO2) cooling emission fluxes. We perform a detailed modeling study of these two similar HSS events with the Global Ionosphere-Thermosphere Model (GITM) and different external driving inputs to understand the IT response and to address how well the model reproduces the energy transport. GITM is run in a mode with forecastable inputs. It is shown that the model captures the main features of the energy coupling, but underestimates NO cooling and auroral heating in high latitudes. Lower thermospheric forcing at 100 km altitude is important for correct energy balance of the IT system. We discuss challenges for a physics-based general forecasting approach in modeling the energy budget of moderate IT storms caused by HSSs.

  18. Jupiter small satellite montage

    Science.gov (United States)

    2000-01-01

    A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo 'prime mission'--and was about to embark on a successful two-year extension, called the Galileo Europa Mission. The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views; this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter. The next two images show the moon Amalthea; they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that 'leads' as Amalthea moves in its orbit around Jupiter. This image looks 'noisy' because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent 'spots' of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis. In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles); Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles); Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles); Amalthea on November 7, 1997 at a

  19. A Day on Jupiter (Animation)

    Science.gov (United States)

    2007-01-01

    This 'movie' strings 11 images of Jupiter captured by the New Horizons Long Range Reconnaissance Imager (LORRI) on January 9, 2007, when the spacecraft was about 80 million kilometers (49.6 million miles) from the giant planet. The sequence covers a full 10-hour rotation of Jupiter, during which the moons Ganymede and Io -- as well as the shadows they cast on Jupiter -- move across the camera's field of view.

  20. Observations and simulations of midlatitude ionospheric and thermospheric response to the January 2013 stratospheric sudden warming event

    Science.gov (United States)

    Wu, Qian; Maute, A.; Yudin, V.; Goncharenko, L.; Noto, J.; Kerr, R.; Jacobi, Christoph

    2016-09-01

    Using observations from midlatitudes, we examine the ionospheric and thermospheric responses to the 2013 stratospheric sudden warming event by comparing data with four simulations performed by the Whole Atmosphere Community Climate Model eXtended (WACCM-X), Thermosphere-Ionosphere Mesosphere Electrodynamics General Circulation Model (TIMEGCM), and Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIEGCM). The WACCM-X simulation was nudged by the GEOS-5 data. The two TIMEGCM simulations were nudged by the Modern-Era Retrospective analysis for Research and Applications data and by the aforementioned WACCM-X outputs, respectively. The standard TIEGCM simulation was also performed. These four simulations were compared with Millstone Hill (42.6°N, 71.4°W) incoherent scatter radar data, Millstone Hill and Boulder (40.1°N, 105.2°W) upper and lower thermospheric wind data. The meteor radar data from Collm (51.3°N, 13°E) were also used to examine the zonal wave number of the semidiurnal tide (SD). We evaluate the model simulations of the mesospheric and thermospheric responses to the 2013 SSW. The TIMEGCM simulation nudged with the WACCM-X output has suitable stratospheric input and ionospheric dynamics and can reproduce a sharp rise of hmf2 on January 12 observed by the Millstone Hill radar. The comparison of different models with the lower thermospheric SD tide yielded mixed results. The SD tide maintained mostly as a migrating tide for most of the time and matched the TIEGCM simulation very well. The WACCM-X appeared to perform better when the observed SD tide displays the large phase shift. It also has larger and more variable SD tide amplitude. The two TIMEGCM simulations have smaller SD amplitudes in general. Observations showed complex SD tide patterns after 20 January, which was difficult to characterize as a migrating tidal mode.

  1. Jupiter: Lord of the Planets.

    Science.gov (United States)

    Kaufmann, William

    1984-01-01

    Presents a chapter from an introductory college-level astronomy textbook in which full-color photographs and numerous diagrams highlight an extensive description of the planet Jupiter. Topics include Jupiter's geology, rotation, magnetic field, atmosphere (including clouds and winds), and the Great Red Spot. (DH)

  2. Small Friends of Hot Jupiters

    Science.gov (United States)

    Nunez, Luis Ernesto; Johnson, John A.

    2017-01-01

    Hot Jupiters are Jupiter-sized gas giant exoplanets that closely orbit their host star in periods of about 10 days or less. Early models hypothesized that these exoplanets formed away from the star, then over time drifted to their characteristically closer locations. However, new theories predict that Hot Jupiters form at their close proximity during the process of core accretion (Batygin et al. 2015). In fact, a super-Earth and a Neptune-sized exoplanet have already been detected in the Hot Jupiter-hosting star WASP-47 (Becker et al. 2015). We will present our analysis of radial velocity time series plots to determine whether low-mass, short-period planets have been previously overlooked in systems of stars which host Hot Jupiters.The SAO REU program is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851.

  3. Thermospheric recovery during the 5 April 2010 geomagnetic storm

    Science.gov (United States)

    Sheng, Cheng; Lu, Gang; Solomon, Stanley C.; Wang, Wenbin; Doornbos, Eelco; Hunt, Linda A.; Mlynczak, Martin G.

    2017-04-01

    Thermospheric temperature and density recovery during the 5 April 2010 geomagnetic storm has been investigated in this study. Neutral density recovery as revealed by Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) simulations was slower than observations from GOCE, CHAMP, and GRACE satellites, suggesting that the cooling processes may not be fully represented in the model. The NO radiative cooling rate in TIEGCM was also compared with TIMED/SABER measurements along satellite orbits during this storm period. It was found that the model overestimated the NO cooling rate at low latitudes and underestimated it at high latitudes. The effects of particle precipitation on NO number density and NO cooling rate at high latitudes were examined in detail. Model experiments showed that while NO number density and NO cooling rate do change with different specifications of the characteristic energy of auroral precipitating electrons, neutral temperature and density recovery remain more or less the same. The reaction rates of key NO chemistry were tested as well, and the NO number density between 110 and 150 km was found to be very sensitive to the reaction rate of N(2D) + O2 → NO + O. A temperature-dependent reaction rate for this reaction proposed by Duff et al. (2003) brought the TIEGCM NO cooling rate at high latitudes closer to the SABER observations. With the temperature-dependent reaction rate, the neutral density recovery time became quite close to the observations in the high-latitude Southern Hemisphere. But model-data discrepancies still exist at low latitudes and in the Northern Hemisphere, which calls for further investigation.

  4. Warm Jupiters are less lonely than hot Jupiters: close neighbours

    CERN Document Server

    Huang, Chelsea X; Triaud, Amaury H M J

    2016-01-01

    Exploiting the Kepler transit data, we uncover a dramatic distinction in the prevalence of sub-Jovian companions, between systems that contain hot Jupiters (periods inward of 10 days) and those that host warm Jupiters (periods between 10 and 200 days). Hot Jupiters as a whole, with the singular exception of WASP-47b, do not have any detectable inner or outer planetary companions (with periods inward of 50 days and sizes down to $2 R_{\\rm Earth}$). Restricting ourselves to inner companions, our limits reach down to $1 R_{\\rm Earth}$. In stark contrast, half of the warm Jupiters are closely flanked by small companions. Statistically, the companion fractions for hot and warm Jupiters are mutually exclusive, in particular in regard to inner companions. The high companion fraction of warm Jupiters also yields clue to their formation. The warm Jupiters that have close-by siblings should have low orbital eccentricities and low mutual inclinations. The orbital configurations of these systems are reminiscent of those ...

  5. Thermal structure of Venus upper atmosphere by a ground-to-thermosphere GCM: a preliminary study

    Science.gov (United States)

    Gilli, G.; Lebonnois, S.; Salmi, L.; Gonzalez-Galindo, F.; Lopez-Valverde, M. A.; Eymet, V.; Forget, F.

    2014-04-01

    We present here preliminary results of the thermal structure of the upper atmosphere of Venus simulated by a ground-to thermosphere General Circulation Model (GCM). The GCM developed at the Laboratoire de Meteorologie Dynamique (LMD) [1] has been recently improved and extended vertically from 100 to 150 km, with the inclusion of the physical processes which mostly contribute to the thermal balance in the mesosphere/thermosphere of Venus (i.e near IR heating by CO2, 15 μm thermal cooling, extreme UV heating, thermal conduction). We also focus on recent Venus Express and ground-based temperature measurements above 100 km, both at daytime and nighttime, and we interpret the observed main features with the help of model simulations. This ongoing study may indicate that both radiative and dynamical effects play a crucial role in determining the thermal structure of those upper layers of Venus atmosphere.

  6. Variability of the Martian thermospheric temperatures during the last 7 Martian Years

    Science.gov (United States)

    Gonzalez-Galindo, Francisco; Lopez-Valverde, Miguel Angel; Millour, Ehouarn; Forget, François

    2014-05-01

    The temperatures and densities in the Martian upper atmosphere have a significant influence over the different processes producing atmospheric escape. A good knowledge of the thermosphere and its variability is thus necessary in order to better understand and quantify the atmospheric loss to space and the evolution of the planet. Different global models have been used to study the seasonal and interannual variability of the Martian thermosphere, usually considering three solar scenarios (solar minimum, solar medium and solar maximum conditions) to take into account the solar cycle variability. However, the variability of the solar activity within the simulated period of time is not usually considered in these models. We have improved the description of the UV solar flux included on the General Circulation Model for Mars developed at the Laboratoire de Météorologie Dynamique (LMD-MGCM) in order to include its observed day-to-day variability. We have used the model to simulate the thermospheric variability during Martian Years 24 to 30, using realistic UV solar fluxes and dust opacities. The model predicts and interannual variability of the temperatures in the upper thermosphere that ranges from about 50 K during the aphelion to up to 150 K during perihelion. The seasonal variability of temperatures due to the eccentricity of the Martian orbit is modified by the variability of the solar flux within a given Martian year. The solar rotation cycle produces temperature oscillations of up to 30 K. We have also studied the response of the modeled thermosphere to the global dust storms in Martian Year 25 and Martian Year 28. The atmospheric dynamics are significantly modified by the global dust storms, which induces significant changes in the thermospheric temperatures. The response of the model to the presence of both global dust storms is in good agreement with previous modeling results (Medvedev et al., Journal of Geophysical Research, 2013). As expected, the simulated

  7. Jupiter's Moons: Family Portrait

    Science.gov (United States)

    2007-01-01

    This montage shows the best views of Jupiter's four large and diverse 'Galilean' satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter. Io, 3,640 kilometers (2,260 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.7 million kilometers (1.7 million miles). The original image scale was 13 kilometers per pixel, and the image is centered at Io coordinates 6 degrees south, 22 degrees west. Io is notable for its active volcanism, which New Horizons has studied extensively. Europa, 3,120 kilometers (1,938 miles) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 3 million kilometers (1.8 million miles). The original image scale was 15 kilometers per pixel, and the image is centered at Europa coordinates 6 degrees south, 347 degrees west. Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa's surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it. New Horizons spied Ganymede, 5,262 kilometers (3,268 miles) in diameter, at 10:01 Universal Time on February 27 from 3.5 million kilometers (2.2 million miles) away. The original scale was 17 kilometers per pixel, and the image is centered at Ganymede coordinates 6 degrees south, 38 degrees west. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior. Callisto, 4,820 kilometers (2,995 miles) in diameter, was imaged at 03:50 Universal Time on

  8. Small Inner Companions of Warm Jupiters: Lifetimes and Legacies

    CERN Document Server

    Van Laerhoven, Christa

    2014-01-01

    Although warm jupiters are generally too far from their stars for tides to be important, the presence of an inner planetary companion to a warm jupiter can result in tidal evolution of the system. Insight into the process and its effects comes form classical secular theory of planetary perturbations. The lifetime of the inner planet may be shorter than the age of the system, because the warm jupiter maintains its eccentricity and hence promotes tidal migration into the star. Thus a warm jupiter observed to be alone in its system might have previously cleared away any interior planets. Before its demise, even if an inner planet is of terrestrial scale, it may promote damping of the warm jupiter's eccentricity. Thus any inferences of the initial orbit of an observed warm jupiter must include the possibility of a greater initial eccentricity than would be estimated by assuming it had always been alone. Tidal evolution involving multiple planets also enhances the internal heating of the planets, which readily exc...

  9. Solar wind influence on Jupiter's aurora

    Science.gov (United States)

    Gyalay, Szilard; Vogt, Marissa F.; Withers, Paul; Bunce, Emma J.

    2016-10-01

    Jupiter's main auroral emission is driven by a system of corotation enforcement currents that arises to speed up outflowing Iogenic plasma and is not due to the magnetosphere-solar wind interaction like at Earth. The solar wind is generally expected to have only a small influence on Jupiter's magnetosphere and aurora compared to the influence of rotational stresses due to the planet's rapid rotation. However, there is considerable observational evidence that the solar wind does affect the magnetopause standoff distance, auroral radio emissions, and the position and brightness of the UV auroral emissions. Using the Michigan Solar Wind Model (mSWiM) to predict the solar wind conditions upstream of Jupiter we have identified intervals of high and low solar wind dynamic pressure in the Galileo dataset, and use this information to quantify how a magnetospheric compression affects the magnetospheric field configuration. We have developed separate spatial fits to the compressed and nominal magnetic field data, accounting for variations with radial distance and local time. These two fits can be used to update the flux equivalence mapping model of Vogt et al. (2011), which links auroral features to source regions in the middle and outer magnetosphere. The updated version accounts for changing solar wind conditions and provides a way to quantify the expected solar wind-induced variability in the ionospheric mapping of the main auroral emission, satellite footprints, and other auroral features. Our results are highly relevant to interpretation of the new auroral observations from the Juno mission.

  10. Jupiter Icy Moons Explorer: mission status after the Definition Phase

    Science.gov (United States)

    Titov, Dmitri; Barabash, Stas; Bruzzone, Lorenzo; Dougherty, Michele; Erd, Christian; Fletcher, Leigh; Gare, Philippe; Gladstone, Randall; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Langevin, Yves; Palumbo, Pasquale; Piccioni, Giuseppe; Sarri, Giuseppe; Wahlund, Jan-Erik; Witasse, Olivier

    2015-04-01

    JUpiter ICy moons Explorer (JUICE), the ESA first large-class mission within the Cosmic Vision Program 2015-2025, was adopted in November 2014. The mission will perform detailed investigations of Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. The overarching theme for JUICE is: The emergence of habitable worlds around gas giants. At Ganymede, the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions will be elucidated. JUICE will study the moons' interactions with the magnetosphere, gravitational coupling and long-term tidal evolution of the Galilean satellites. JUICE highly capable scientific payload includes 10 state-of-the-art instruments onboard the spacecraft plus one experiment that uses the spacecraft telecommunication system with ground-based radio telescopes. The remote sensing package includes a high-resolution multi-band visible imager (JANUS) and spectro-imaging capabilities from the

  11. Wavelength Dependence of Solar Flare Irradiation and its Influence on the Thermosphere

    Science.gov (United States)

    Huang, Yanshi; Richmond, Arthur D.; Deng, Yue; Qian, L.; Solomon, S.; Chamberlin, P.

    2012-01-01

    The wavelength dependence of solar flare enhancement is one of the important factors determining how the Thermosphere-Ionosphere (T-I) system response to flares. To investigate the wavelength dependence of solar flare, the Flare Irradiance Spectral Model (FISM) has been run for 34 X-class flares. The results show that the percentage increases of solar irradiance at flare peak comparing to pre-flare condition have a clear wavelength dependence. In the wavelength range between 0 - 195 nm, it can vary from 1% to 10000%. The solar irradiance enhancement is largest ( 1000%) in the XUV range (0 - 25 nm), and is about 100% in EUV range (25 - 120 nm). The influence of different wavebands on the T-I system during the October 28th, 2003 flare (X17.2-class) has also been examined using the latest version of National Center for Atmospheric Research (NCAR) Thermosphere- Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). While the globally integrated solar energy deposition is largest in the 0 - 14 nm waveband, the impact of solar irradiance enhancement on the thermosphere at 400 km is largest for 25 - 105 nm waveband. The effect of 122 - 195 nm is small in magnitude, but it decays slowly.

  12. 3-D GCM modelling of thermospheric nitric oxide during the 2003 Halloween storm

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, A.L.; Griffin, E.M.; Aylward, A.D.; Millward, G.H. [University College London (United Kingdom). Atmospheric Physics Lab.

    2006-07-01

    Numerical modelling of thermospheric temperature changes associated with periods of high geomagnetic activity are often inaccurate due to unrealistic representation of nitric oxide (NO) densities and associated 5.3-{mu}m radiative cooling. In previous modelling studies, simplistic parameterisations of NO density and variability have often been implemented in order to constrain thermospheric temperature predictions and post storm recovery timescales during and following periods of high auroral activity. In this paper we use the University College London (UCL) 3-D Coupled Thermosphere and Middle Atmosphere (CMAT) General Circulation Model to simulate the 11-day period from 23 October to 3 November 2003, during which the Earth experienced some of the largest geomagnetic activity ever recorded; the so called ''Halloween storm''. This model has recently been updated to include a detailed self consistent calculation of NO production and transport. Temperatures predicted by the model compare well with those observed by the UCL Fabry Perot Interferometer at Kiruna, northern Sweden, when changes in solar and auroral activity are taken into account in the calculation of NO densities. The spatial distribution of predicted temperatures at approximately 250-km altitude is also discussed. Simulated NO densities at approximately 110 km are presented. Large quantities of NO are found to be present at to the equator, one to two days after the most intense period of geomagnetic activity. This is the first 3-D GCM simulation of NO production and transport over the 2003 Halloween storm period. (orig.)

  13. Thermal structure of the upper atmosphere of Venus simulated by a ground-to-thermosphere GCM

    Science.gov (United States)

    Gilli, G.; Lebonnois, S.; González-Galindo, F.; López-Valverde, M. A.; Stolzenbach, A.; Lefèvre, F.; Chaufray, J. Y.; Lott, F.

    2017-01-01

    We present here the thermal structure of the upper atmosphere of Venus predicted by a full self-consistent Venus General Circulation Model (VGCM) developed at Laboratoire de Météorologie Dynamique (LMD) and extended up to the thermosphere of the planet. Physical and photochemical processes relevant at those altitudes, plus a non-orographic GW parameterisation, have been added. All those improvements make the LMD-VGCM the only existing ground-to-thermosphere 3D model for Venus: a unique tool to investigate the atmosphere of Venus and to support the exploration of the planet by remote sounding. The aim of this paper is to present the model reference results, to describe the role of radiative, photochemical and dynamical effects in the observed thermal structure in the upper mesosphere/lower thermosphere of the planet. The predicted thermal structure shows a succession of warm and cold layers, as recently observed. A cooling trend with increasing latitudes is found during daytime at all altitudes, while at nighttime the trend is inverse above about 110 km, with an atmosphere up to 15 K warmer towards the pole. The latitudinal variation is even smaller at the terminator, in agreement with observations. Below about 110 km, a nighttime warm layer whose intensity decreases with increasing latitudes is predicted by our GCM. A comparison of model results with a selection of recent measurements shows an overall good agreement in terms of trends and order of magnitude. Significant data-model discrepancies may be also discerned. Among them, thermospheric temperatures are about 40-50 K colder and up to 30 K warmer than measured at terminator and at nighttime, respectively. The altitude layer of the predicted mesospheric local maximum (between 100 and 120 km) is also higher than observed. Possible interpretations are discussed and several sensitivity tests performed to understand the data-model discrepancies and to propose future model improvements.

  14. Upper thermospheric neutral wind and temperature measurements from an extended spatial field

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, E.M.; Aruliah, A.L.; McWhirter, I.; Yiu, H.C.I.; Charalambous, A. [University College London (United Kingdom). Atmospheric Physics Lab.; McCrea, I. [Rutherford Appleton Lab., Chilton, Didcot (United Kingdom). EISCAT Support Group

    2008-07-01

    First results are presented from a Scanning Doppler Imager (SCANDI) installed at the Nordlysstasjonen optical observatory near Longyearbyen, Svalbard (78.2 N, 15.8 E). Observations of the atomic oxygen 630 nm red line emission, originating in the upper thermosphere at around 250 km, have been used to determine neutral winds and temperatures from multiple zones within an extended spatial field. The instrument utilises all-sky optics to achieve multiple simultaneous measurements, compared to the standard Fabry-Perot Interferometer (FPI) procedure of separate line-of-sight samples within a sequence of narrow angle look directions. SCANDI is colocated with such a standard FPI and comparison of neutral wind velocities between the instruments on the night of 15 March 2007 has revealed detailed and consistent structure in the wind field. Southward meridional wind enhancements of several hundred m/s are observed simultaneously with both instruments, revealing structure on scales not currently considered in thermospheric general circulation models (GCMs). The data from this night also demonstrate the influence of discrete auroral events on thermospheric behaviour. High intensities observed by SCANDI in the presence of auroral arcs coincide with a drop in measured neutral temperatures. This is interpreted as a result of the effective altitude of the 630 nm emission being lowered under conditions of soft auroral precipitation. The optical instruments as a consequence sample a region of lower temperature. This effect has been observed previously with lower thermospheric atomic oxygen emissions at 557.7 nm. The EISCAT Svalbard Radar (ESR) provides ion temperatures and electron densities for the night which confirm the influence of precipitation and heating during the auroral events. The minima of ion temperatures through the pre-midnight period provide a good match to the neutral temperatures measured with SCANDI, and to the colocated FPI temperatures. (orig.)

  15. Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

    Science.gov (United States)

    Häusler, K.; Hagan, M. E.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

    2015-01-01

    In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulation for 2009, which is characterized by low solar and geomagnetic activity. In order to account for tropospheric waves and tides propagating upward into the ˜30-400 km model domain, we used 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data. We focus on exospheric tidal temperatures, which are also compared with 72 day mean determinations from combined Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellite observations to assess the model's capability to capture the observed tidal signatures and to quantify the uncertainties associated with the satellite exospheric temperature determination technique. We found strong day-to-day tidal variability in TIME-GCM that is smoothed out when averaged over as few as ten days. TIME-GCM notably overestimates the 72 day mean eastward propagating tides observed by CHAMP/GRACE, while capturing many of the salient features of other tidal components. However, the CHAMP/GRACE tidal determination technique only provides a gross climatological representation, underestimates the majority of the tidal components in the climatological spectrum, and moreover fails to characterize the extreme variability that drives the dynamics and electrodynamics of the ionosphere-thermosphere system. A multisatellite mission that samples at least six local times simultaneously is needed to provide this quantification.

  16. Jupiter Clouds in Depth

    Science.gov (United States)

    2000-01-01

    [figure removed for brevity, see original site] 619 nm [figure removed for brevity, see original site] 727 nm [figure removed for brevity, see original site] 890 nmImages from NASA's Cassini spacecraft using three different filters reveal cloud structures and movements at different depths in the atmosphere around Jupiter's south pole.Cassini's cameras come equipped with filters that sample three wavelengths where methane gas absorbs light. These are in the red at 619 nanometer (nm) wavelength and in the near-infrared at 727 nm and 890 nm. Absorption in the 619 nm filter is weak. It is stronger in the 727 nm band and very strong in the 890 nm band where 90 percent of the light is absorbed by methane gas. Light in the weakest band can penetrate the deepest into Jupiter's atmosphere. It is sensitive to the amount of cloud and haze down to the pressure of the water cloud, which lies at a depth where pressure is about 6 times the atmospheric pressure at sea level on the Earth). Light in the strongest methane band is absorbed at high altitude and is sensitive only to the ammonia cloud level and higher (pressures less than about one-half of Earth's atmospheric pressure) and the middle methane band is sensitive to the ammonia and ammonium hydrosulfide cloud layers as deep as two times Earth's atmospheric pressure.The images shown here demonstrate the power of these filters in studies of cloud stratigraphy. The images cover latitudes from about 15 degrees north at the top down to the southern polar region at the bottom. The left and middle images are ratios, the image in the methane filter divided by the image at a nearby wavelength outside the methane band. Using ratios emphasizes where contrast is due to methane absorption and not to other factors, such as the absorptive properties of the cloud particles, which influence contrast at all wavelengths.The most prominent feature seen in all three filters is the polar stratospheric haze that makes Jupiter bright near the pole

  17. Jupiter Eruptions Captured in Infrared

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers. This infrared image shows two bright plume eruptions obtained by the NASA Infrared Telescope Facility on April 5, 2007. Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena. According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vigorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  18. Jupiter's radiation belts and atmosphere

    Science.gov (United States)

    De Pater, I.; Dames, H. A. C.

    1979-01-01

    Maps and stripscans of the radio emission from Jupiter were made during the Pioneer 10 flyby in December 1973 at wavelengths of 6 cm, 21 cm, and 50 cm using the Westerbork telescope in the Netherlands. With this instrument the disk of the planet was resolved at 6 and 21 cm. The pictures are averaged over 15 deg of Jovian longitude. At 21 cm the stripscans clearly show the existence of a 'hot region' in the radiation belts at a System III longitude (1965.0) of 255 + or - 10 deg. Its flux is about 9% of the total nonthermal flux, and it has a volume emissivity enhanced by a factor of about 1.6 with respect to the general radiation belts. The temperature of the thermal disk at 21 cm appears to be 290 + or - 20 K. This is likely due to a high ammonia mixing ratio in the atmosphere, a factor of 4-5 larger than the expected solar value of 0.00015.

  19. Japanese mission plan for Jupiter system: The Jupiter magnetospheric orbiter and the Trojan asteroid explorer

    Science.gov (United States)

    Sasaki, S.; Fujimoto, M.; Yano, H.; Takashima, T.; Kasaba, Y.; Takahashi, Y.; Kimura, J.; Funase, R.; Mori, O.; Tsuda, Y.; Campagnola, S.; Kawakatsu, Y.

    2011-10-01

    In the future Jupiter system study, Coordinated observation of Jovian magnetosphere is one of the important targets of the mission in addition to icy satellites, atmosphere, and interior of Jupiter. JAXA will take a role on the magnetosphere spinner JMO (Jupiter Magnetospheric Orbiter), in addition to JGO (Jupiter Ganymede Orbiter) by ESA and JEO (Jupiter Europa Orbiter) by NASA. We will combine JMO with a proposed solar sail mission of JAXA for Jupiter and one of Trojan asteroids. Since Trojan asteroids could be representing raw solid materials of Jupiter or at least outer solar system bodies, involvement of Trojan observation should enhance the quality of Jupiter system exploration.

  20. Consistent Static Models of Local Thermospheric Composition Profiles

    CERN Document Server

    Picone, J M; Drob, D P

    2016-01-01

    The authors investigate the ideal, nondriven multifluid equations of motion to identify consistent (i.e., truly stationary), mechanically static models for composition profiles within the thermosphere. These physically faithful functions are necessary to define the parametric core of future empirical atmospheric models and climatologies. Based on the strength of interspecies coupling, the thermosphere has three altitude regions: (1) the lower thermosphere (herein z ~200 km), in which the species flows are approximately uncoupled; and (3) a transition region in between, where the effective species particle mass and the effective species vertical flow interpolate between the solutions for the upper and lower thermosphere. We place this view in the context of current terminology within the community, i.e., a fully mixed (lower) region and an upper region in diffusive equilibrium (DE). The latter condition, DE, currently used in empirical composition models, does not represent a truly static composition profile ...

  1. ADAPTIVE MODEL REFINEMENT FOR THE IONOSPHERE AND THERMOSPHERE

    Data.gov (United States)

    National Aeronautics and Space Administration — ADAPTIVE MODEL REFINEMENT FOR THE IONOSPHERE AND THERMOSPHERE ANTHONY M. D’AMATO∗, AARON J. RIDLEY∗∗, AND DENNIS S. BERNSTEIN∗∗∗ Abstract. Mathematical models of...

  2. Parameterization of Nitric Oxide Emissions in the Thermosphere

    Science.gov (United States)

    Lin, C. Y. T.; Deng, Y.; Venkataramani, K.; Yonker, J. D.; Bailey, S. M.

    2016-12-01

    Nitric oxide (NO), a minor species in the thermosphere, is an important indicator of energy balance. It also has the lowest ionization threshold so is the terminal ion in the ionospheric E-region. Discrepancies between observations and modeled results challenge current understanding of ionospheric and thermospheric energy budget especially during geophysical events. Work in the recent decades has significantly improved our understanding of the NO chemistry and in particular its relationship to energy inputs, such as the role of the excited state of nitrogen, N2(A), in the NO reactions. We update the NO chemical reactions and introduce N2(A) in the Global Ionosphere Thermosphere Model (GITM) to study NO density and cooling in the lower thermosphere. The results are compared with the TIMED SABER and GUVI measurements to identify the relative contribution from solar irradiance and geomagnetic activity to 5.3 µm emission by NO. A parameterization scheme is proposed to be used in a global circulation model.

  3. Non-thermal hydrogen atoms in the terrestrial upper thermosphere.

    Science.gov (United States)

    Qin, Jianqi; Waldrop, Lara

    2016-12-06

    Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen atoms in the upper thermosphere. Analysis of satellite measurements indicates that the upper thermospheric hydrogen temperature, more precisely the mean kinetic energy of the atomic hydrogen population, increases significantly with declining solar activity, contrary to contemporary understanding of thermospheric behaviour. The existence of hot hydrogen atoms in the upper thermosphere, which is the key to reconciling model predictions and observations, is likely a consequence of low atomic oxygen density leading to incomplete collisional thermalization of the hydrogen population following its kinetic energization through interactions with hot atomic or ionized constituents in the ionosphere, plasmasphere or magnetosphere.

  4. An exospheric temperature model from CHAMP thermospheric density

    Science.gov (United States)

    Weng, Libin; Lei, Jiuhou; Sutton, Eric; Dou, Xiankang; Fang, Hanxian

    2017-02-01

    In this study, the effective exospheric temperature, named as T∞, derived from thermospheric densities measured by the CHAMP satellite during 2002-2010 was utilized to develop an exospheric temperature model (ETM) with the aid of the NRLMSISE-00 model. In the ETM, the temperature variations are characterized as a function of latitude, local time, season, and solar and geomagnetic activities. The ETM is validated by the independent GRACE measurements, and it is found that T∞ and thermospheric densities from the ETM are in better agreement with the GRACE data than those from the NRLMSISE-00 model. In addition, the ETM captures well the thermospheric equatorial anomaly feature, seasonal variation, and the hemispheric asymmetry in the thermosphere.

  5. Ionosphere-Thermosphere Coupling - Data Analysis and Numerical Simulation Study

    Science.gov (United States)

    2013-12-12

    Circulation Model (TIE- GCM) is a first-principles, three-dimensional, non -linear representation of the coupled thermosphere and ionosphere system. It...method for given distributions of precipitating energy fluxes. Note that the parameterization of Roble and Ridley [1987] was designed for a Maxwellian ...results from the non -hydrostatic GCM, GITM and Fang’s parameterization models. 3.3 GITM The Global Ionosphere-Thermosphere Model (GITM) is a three

  6. Jupiter's moon Io

    Science.gov (United States)

    1979-01-01

    This picture shows a special color reconstruction of one of the erupting volcanos on Io discovered by Voyager 1 during its encounter with Jupiter on the 4th and 5th of March. The picture was taken March 4 about 5:00 p.m. from a range of about half a million kilometers showing an eruption region on the horizon. This method of color analysis allows scientists to combine data from four pictures, taken in ultraviolet, blue, green and orange light. In this picture one can see the strong change in color of the erupting plume. The region that is brighter in ultraviolet light (blue in this image) is much more extensive than the denser, bright yellow region near the center of the eruption. Scientists will use data of this type to study the amount of gas and dust in the eruption and the size of dust particles. Preliminary analysis suggests that the bright ultraviolet part of the cloud may be due to scattered light from very fine particles (the same effect which makes smoke appear bluish).

  7. Jupiter's Hot, Mushy Moon

    Science.gov (United States)

    Taylor, G. Jeffrey

    2003-01-01

    Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

  8. Mean thermospheric winds observed from Halley, Antarctica

    Directory of Open Access Journals (Sweden)

    R. I. Crickmore

    Full Text Available Thermospheric winds on a total of 237 nights have been studied for the effects due to geomagnetic activity, solar flux, and season. The observations have been made from 1988 to 1992 by a Fabry-Perot interferometer (FPI operating at Halley (75.5°S, 26.6°W, Antarctica. This is the first statistical study of thermospheric winds near the southern auroral zone. The main factor affecting the wind velocities is the geomagnetic activity. Increases in activity cause an increase in the maximum equatorward wind, and cause the zonal wind in the evening to become more westward. Smaller changes in the mean wind occur with variations in season and solar flux. The small variation with solar flux is more akin to the situation found at mid-latitudes than at high latitudes. Since the geomagnetic latitude of Halley is only 61°, it suggests that the variability of the wind with solar flux may depend more on geomagnetic than geographic latitude. These observations are in good agreement with the empirical Horizontal Wind Model (HWM90. However, comparisons with predictions of the Vector Spherical Harmonic Model (VSH show that for low geomagnetic activity the predicted phases of the two components of the wind closely resemble the observations but the modelled amplitudes are too small by a factor of two. At high geomagnetic activity the major differences are that modelled zonal velocity is too westward in the evening and too eastward after 04 UT. The modelled ion densities at the F-region peak are a factor of up to 9 too large, whilst the predicted mean value and diurnal variation of the altitude of the peak are significantly lower than those observed. It is suggested that these differences result from the ion loss rate being too low, and an inaccurate model of the magnetic field.

  9. Ionospheric and Thermospheric Imaging from Geosynchronous Orbit

    Science.gov (United States)

    McCoy, R. P.; Wood, K.; Dymond, K. F.; Thonnard, S. E.; Cannon, K.; Makela, J.

    2001-12-01

    The Office of Naval Research is sponsoring the development of an ultraviolet imaging system to test the concept of real-time synoptic observations of the ionosphere and thermosphere from geosynchronous orbit. The observational hardware consists of two ultraviolet telescopes mounted to a two-axis gimbal to measure airglow radiances on the disk and limb of the Earth. A far-ultraviolet telescope will use a filter wheel with filters to image atomic oxygen emission at 130.4 nm, 135.6 nm, and molecular nitrogen emission at 143.0 nm. An extreme-ultraviolet telescope will image the oxygen ion airglow at 83.4 nm. The oxygen emission measurements will be used to infer nightside ionospheric total electron content (TEC) on the disk and electron density profiles on the limb. On the dayside the oxygen ion measurements will be used to determine electron density profiles, and the oxygen and nitrogen measurements will be used to infer thermospheric neutral density profiles on the limb and O/N2 ratios on the disk. The telescope fields of view cover a 1000 km x 1000 km region with 10 km x 10 km resolution. A goal for nightside TEC measurements is to obtain images with 100 second integrations and to be able to track ionospheric irregularities in real time as "weather systems". Ratios of oxygen nightglow measurements will be used to explore the possibility of providing three dimensional measurements of the ionosphere. These telescopes will be mounted aboard an Air Force Space Test Program satellite which will be launched into geosynchronous orbit over the continental U. S. for about year and then moved over the Indian Ocean for an additional seven years.

  10. Response of thermosphere density to high-latitude forcing

    Science.gov (United States)

    Yamazaki, Y.; Kosch, M. J.; Vickers, H.; Sutton, E. K.; Ogawa, Y.

    2014-12-01

    Solar wind-magnetospheric disturbances cause enhancements in the energy input to the high-latitude upper atmosphere through particle precipitation and Joule heating. As the upper atmosphere is heated and expanded during geomagnetically disturbed periods, the neutral density in the thermosphere increases at a fixed altitude. Conversely, the thermosphere contracts during the recovery phase of the disturbance, resulting in a decrease of the density. The main objectives of this study are (1) to determine the morphology of the global thermospheric density response to high-latitude forcing, and (2) to determine the recovery speed of the thermosphere density after geomagnetic disturbances. For (1), we use thermospheric density data measured by the Challenging Minisatellite Payload (CHAMP) satellite during 2000-2010. It is demonstrated that the density enhancement during disturbed periods occurs first in the dayside cusp region, and the density at other regions slowly follows it. The reverse process is observed when geomagnetic activity ceases; the density enhancement in the cusp region fades away first, then the global density slowly goes back to the quiet level. For (2), we analyze EISCAT Svalbard radar and Tromso UHF radar data to estimate thermospheric densities during the recovery phase of geomagnetic disturbances. We attempt to determine the time constant for the density recovery both inside and outside the cusp region.

  11. Types of Hot Jupiter Atmospheres

    Science.gov (United States)

    Bisikalo, Dmitry V.; Kaygorodov, Pavel V.; Ionov, Dmitry E.; Shematovich, Valery I.

    Hot Jupiters, i.e. exoplanet gas giants, having masses comparable to the mass of Jupiter and semimajor axes shorter than 0.1 AU, are a unique class of objects. Since they are so close to the host stars, their atmospheres form and evolve under the action of very active gas dynamical processes caused by the gravitational field and irradiation of the host star. As a matter of fact, the atmospheres of several of these planets fill their Roche lobes , which results in a powerful outflow of material from the planet towards the host star. The energy budget of this process is so important that it almost solely governs the evolution of hot Jupiters gaseous envelopes. Based on the years of experience in the simulations of gas dynamics in mass-exchanging close binary stars, we have investigated specific features of hot Jupiters atmospheres. The analytical estimates and results of 3D numerical simulations, discussed in this Chapter, show that the gaseous envelopes around hot Jupiters may be significantly non-spherical and, at the same time, stationary and long-lived. These results are of fundamental importance for the interpretation of observational data.

  12. Jupiter and Saturn Rotation Periods

    CERN Document Server

    Helled, Ravit; Anderson, John D

    2009-01-01

    Anderson & Schubert (2007, Science,317,1384) proposed that Saturn's rotation period can be ascertained by minimizing the dynamic heights of the 100 mbar isosurface with respect to the geoid; they derived a rotation period of 10h 32m 35s. We investigate the same approach for Jupiter to see if the Jovian rotation period is predicted by minimizing the dynamical heights of its isobaric (1 bar pressure level) surface using zonal wind data. A rotation period of 9h 54m 29s is found. Further, we investigate the minimization method by fitting Pioneer and Voyager occultation radii for both Jupiter and Saturn. Rotation periods of 9h 55m 30s and 10h 32m 35s are found to minimize the dynamical heights for Jupiter and Saturn, respectively. Though there is no dynamical principle requiring the minimization of the dynamical heights of an isobaric surface, the successful application of the method to Jupiter lends support to its relevance for Saturn. We derive Jupiter and Saturn rotation periods using equilibrium theory in ...

  13. Estimation of energy budget of ionosphere-thermosphere system during two CIR-HSS events: observations and modeling

    Directory of Open Access Journals (Sweden)

    Verkhoglyadova Olga

    2016-01-01

    Full Text Available We analyze the energy budget of the ionosphere-thermosphere (IT system during two High-Speed Streams (HSSs on 22–31 January, 2007 (in the descending phase of solar cycle 23 and 25 April–2 May, 2011 (in the ascending phase of solar cycle 24 to understand typical features, similarities, and differences in magnetosphere-ionosphere-thermosphere (IT coupling during HSS geomagnetic activity. We focus on the solar wind energy input into the magnetosphere (by using coupling functions and energy partitioning within the IT system during these intervals. The Joule heating is estimated empirically. Hemispheric power is estimated based on satellite measurements. We utilize observations from TIMED/SABER (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry to estimate nitric oxide (NO and carbon dioxide (CO2 cooling emission fluxes. We perform a detailed modeling study of these two similar HSS events with the Global Ionosphere-Thermosphere Model (GITM and different external driving inputs to understand the IT response and to address how well the model reproduces the energy transport. GITM is run in a mode with forecastable inputs. It is shown that the model captures the main features of the energy coupling, but underestimates NO cooling and auroral heating in high latitudes. Lower thermospheric forcing at 100 km altitude is important for correct energy balance of the IT system. We discuss challenges for a physics-based general forecasting approach in modeling the energy budget of moderate IT storms caused by HSSs.

  14. Upper thermospheric responses to forcing from above and below during 1-10 April 2010: Results from an ensemble of numerical simulations

    Science.gov (United States)

    Hagan, M. E.; Häusler, K.; Lu, G.; Forbes, J. M.; Zhang, X.

    2015-04-01

    In this report we examine the spatial and temporal variability of the quiescent thermosphere leading up to and after the 5 April 2010 geomagnetic disturbance. We attribute the dominant driver of this variability to a combination of tides generated in situ and in the troposphere, stratosphere, and mesosphere. We identify nonmigrating tidal signatures attributable to the latter source that are ubiquitous, persistent, and significant at all thermospheric latitudes. Further, these perturbations underlie the upper atmospheric response to solar geomagnetic disturbances and are measurably altered, along with their migrating counterparts, during the storm. Our investigation is centered on a series of National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model simulations during 1-10 April 2010, including an optimal simulation with lower boundary forcing based on Modern-Era Retrospective Analysis for Research and Application reanalysis data and upper boundary forcing based on satellite and ground magnetometer measurements and the Assimilative Mapping of Ionospheric Electrodynamics procedure and three diagnostic simulations. The differences between the optimal and diagnostic simulations allow us to quantify thermospheric variability attributable to solar geomagnetic forcing and dynamical effects propagating into the thermosphere from below. We find that they can be comparable at high latitudes for some nonmigrating tidal components.

  15. The Europa Jupiter System Mission

    Science.gov (United States)

    Hendrix, A. R.; Clark, K.; Erd, C.; Pappalardo, R.; Greeley, R. R.; Blanc, M.; Lebreton, J.; van Houten, T.

    2009-05-01

    Europa Jupiter System Mission (EJSM) will be an international mission that will achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA are also possible. The baseline EJSM architecture consists of two primary elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). The JEO mission has been selected by NASA as the next Flagship mission to the out solar system. JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupiter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. EJSM will fully addresses high priority science objectives identified by the National Research Council's (NRC's) Decadal Survey and ESA's Cosmic Vision for exploration of the outer solar system. The Decadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission target. EJSM would uniquely address several of the central themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM will investigate the potential habitability of the active ocean-bearing moons Europa and Ganymede, detailing the geophysical, compositional, geological and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the

  16. Radiative and dynamical modeling of Jupiter's atmosphere

    Science.gov (United States)

    Guerlet, Sandrine; Spiga, Aymeric

    2016-04-01

    Jupiter's atmosphere harbours a rich meteorology, with alternate westward and eastward zonal jets, waves signatures and long-living storms. Recent ground-based and spacecraft measurements have also revealed a rich stratospheric dynamics, with the observation of thermal signatures of planetary waves, puzzling meridional distribution of hydrocarbons at odds with predictions of photochemical models, and a periodic equatorial oscillation analogous to the Earth's quasi-biennal oscillation and Saturn's equatorial oscillation. These recent observations, along with the many unanswered questions (What drives and maintain the equatorial oscillations? How important is the seasonal forcing compared to the influence of internal heat? What is the large-scale stratospheric circulation of these giant planets?) motivated us to develop a complete 3D General Circulation Model (GCM) of Saturn and Jupiter. We aim at exploring the large-scale circulation, seasonal variability, and wave activity from the troposphere to the stratosphere of these giant planets. We will briefly present how we adapted our existing Saturn GCM to Jupiter. One of the main change is the addition of a stratospheric haze layer made of fractal aggregates in the auroral regions (poleward of 45S and 30N). This haze layer has a significant radiative impact by modifying the temperature up to +/- 15K in the middle stratosphere. We will then describe the results of radiative-convective simulations and how they compare to recent Cassini and ground-based temperature measurements. These simulations reproduce surprisingly well some of the observed thermal vertical and meridional gradients, but several important mismatches at low and high latitudes suggest that dynamics also plays an important role in shaping the temperature field. Finally, we will present full GCM simulations and discuss the main resulting features (waves and instabilities). We will also and discuss the impact of the choice of spatial resolution and

  17. New Concept for Internal Heat Production in Hot Jupiter Exo-Planets

    CERN Document Server

    Herndon, J M

    2006-01-01

    Discovery of hot Jupiter exo-planets, those with anomalously inflated size and low density relative to Jupiter, has evoked much discussion as to possible sources of internal heat production. But to date, no explanations have come forth that are generally applicable. The explanations advanced typically involve presumed tidal dissipation and/or converted incident stellar radiation. The present, brief communication suggests a novel interfacial nuclear fission-fusion source of internal heat production for hot Jupiters that has been overlooked by theoreticians and which has potentially general applicability.

  18. Acoustic Resonance between Ground and Thermosphere

    Directory of Open Access Journals (Sweden)

    M Matsumura

    2009-04-01

    Full Text Available Ultra-low frequency acoustic waves called "acoustic gravity waves" or "infrasounds" are theoretically expected to resonate between the ground and the thermosphere. This resonance is a very important phenomenon causing the coupling of the solid Earth, neutral atmosphere, and ionospheric plasma. This acoustic resonance, however, has not been confirmed by direct observations. In this study, atmospheric perturbations on the ground and ionospheric disturbances were observed and compared with each other to confirm the existence of resonance. Atmospheric perturbations were observed with a barometer, and ionospheric disturbances were observed using the HF Doppler method. An end point of resonance is in the ionosphere, where conductivity is high and the dynamo effect occurs. Thus, geomagnetic observation is also useful, so the geomagnetic data were compared with other data. Power spectral density was calculated and averaged for each month. Peaks appeared at the theoretically expected resonance frequencies in the pressure and HF Doppler data. The frequencies of the peaks varied with the seasons. This is probably because the vertical temperature profile of the atmosphere varies with the seasons, as does the reflection height of infrasounds. These results indicate that acoustic resonance occurs frequently.

  19. Super-Eccentric Migrating Jupiters

    CERN Document Server

    Socrates, Aristotle; Dong, Subo; Tremaine, Scott

    2011-01-01

    An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e=0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e>0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is \\dot a \\propto a^0.5 and consequently the number distribution satisfies dN/dlog a\\propto a^0.5. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios.

  20. SUPER-ECCENTRIC MIGRATING JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Socrates, Aristotle; Katz, Boaz; Dong Subo; Tremaine, Scott [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2012-05-10

    An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e = 0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e > 0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is a-dot {proportional_to}a{sup 1/2} and consequently the number distribution satisfies dN/d log a{proportional_to}a{sup 1/2}. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios.

  1. Jupiter: Cosmic Jekyll and Hyde.

    Science.gov (United States)

    Grazier, Kevin R

    2016-01-01

    It has been widely reported that Jupiter has a profound role in shielding the terrestrial planets from comet impacts in the Solar System, and that a jovian planet is a requirement for the evolution of life on Earth. To evaluate whether jovians, in fact, shield habitable planets from impacts (a phenomenon often referred to as the "Jupiter as shield" concept), this study simulated the evolution of 10,000 particles in each of the jovian inter-planet gaps for the cases of full-mass and embryo planets for up to 100 My. The results of these simulations predict a number of phenomena that not only discount the "Jupiter as shield" concept, they also predict that in a Solar System like ours, large gas giants like Saturn and Jupiter had a different, and potentially even more important, role in the evolution of life on our planet by delivering the volatile-laden material required for the formation of life. The simulations illustrate that, although all particles occupied "non-life threatening" orbits at their onset of the simulations, a significant fraction of the 30,000 particles evolved into Earth-crossing orbits. A comparison of multiple runs with different planetary configurations revealed that Jupiter was responsible for the vast majority of the encounters that "kicked" outer planet material into the terrestrial planet region, and that Saturn assisted in the process far more than has previously been acknowledged. Jupiter also tends to "fix" the aphelion of planetesimals at its orbit irrespective of their initial starting zones, which has the effect of slowing their passages through the inner Solar System, and thus potentially improving the odds of accretion of cometary material by terrestrial planets. As expected, the simulations indicate that the full-mass planets perturb many objects into the deep outer Solar System, or eject them entirely; however, planetary embryos also did this with surprising efficiency. Finally, the simulations predict that Jupiter's capacity to

  2. Equatorial Oscillations in Jupiter's and Saturn's Atmospheres

    Science.gov (United States)

    Flasar, F. Michael; Guerlet, S.; Fouchet, T.; Schinder, P. J.

    2011-01-01

    Equatorial oscillations in the zonal-mean temperatures and zonal winds have been well documented in Earth's middle atmosphere. A growing body of evidence from ground-based and Cassini spacecraft observations indicates that such phenomena also occur in the stratospheres of Jupiter and Saturn. Earth-based midinfrared measurements spanning several decades have established that the equatorial stratospheric temperatures on Jupiter vary with a cycle of 4-5 years and on Saturn with a cycle of approximately 15 years. Spectra obtained by the Composite Infrared Spectrometer (CIRS) during the Cassini swingby at the end of 2000, with much better vertical resolution than the ground-based data, indicated a series of vertically stacked warm and cold anomalics at Jupiter's equator; a similar structurc was seen at Saturn's equator in CIRS limb measurements made in 2005, in the early phase of Cassini's orbital tour. The thermal wind equation implied similar patterns of mean zonal winds increasing and decreasing with altitude. On Saturn the peak-to-pcak amplitude of this variation was nearly 200 meters per second. The alternating vertical pattern of wanner and colder cquatorial tcmperatures and easterly and westerly tendencies of the zonal winds is seen in Earth's equatorial oscillations, where the pattern descends with time, The Cassini Jupiter and early Saturn observations were snapshots within a limited time interval, and they did not show the temporal evolution of the spatial patterns. However, more recent Saturn observations by CIRS (2010) and Cassini radio-occultation soundings (2009-2010) have provided an opportunity to follow the change of the temperature-zonal wind pattern, and they suggest there is descent, at a rate of roughly one scale height over four years. On Earth, the observed descent in the zonal-mean structure is associated with the absorption of a combination of vertically propagating waves with easlerly and westerly phase velocities. The peak-to-peak zonal wind

  3. Featured Image: Mapping Jupiter with Hubble

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    Zonal wind profile for Jupiter, describing the speed and direction of its winds at each latitude. [Simon et al. 2015]This global map of Jupiters surface (click for the full view!) was generated by the Hubble Outer Planet Atmospheres Legacy (OPAL) program, which aims to createnew yearly global maps for each of the outer planets. Presented in a study led by Amy Simon (NASA Goddard Space Flight Center), the map above is the first generated for Jupiter in the first year of the OPAL campaign. It provides a detailed look at Jupiters atmospheric structure including the Great Red Spot and allowed the authors to measure the speed and direction of the wind across Jupiters latitudes, constructing an updated zonal wind profile for Jupiter.In contrast to this study, the Juno mission (which will be captured into Jupiters orbit today after a 5-year journey to Jupiter!) will be focusing more on the features below Jupiters surface, studying its deep atmosphere and winds. Some of Junos primary goals are to learn about Jupiters composition, gravitational field, magnetic field, and polar magnetosphere. You can follow along with the NASATV livestream as Juno arrives at Jupiter tonight; orbit insertion coverage starts at 10:30 EDT.CitationAmy A. Simon et al 2015 ApJ 812 55. doi:10.1088/0004-637X/812/1/55

  4. Io in Front of Jupiter

    Science.gov (United States)

    2000-01-01

    Jupiter's four largest satellites, including Io, the golden ornament in front of Jupiter in this image from NASA's Cassini spacecraft, have fascinated Earthlings ever since Galileo Galilei discovered them in 1610 in one of his first astronomical uses of the telescope.Images from Cassini that will be released over the next several days capture each of the four Galilean satellites in their orbits around the giant planet.This true-color composite frame, made from narrow angle images taken on Dec. 12, 2000, captures Io and its shadow in transit against the disk of Jupiter. The distance of the spacecraft from Jupiter was 19.5 million kilometers (12.1 million miles). The image scale is 117 kilometers (73 miles) per pixel.The entire body of Io, about the size of Earth's Moon, is periodically flexed as it speeds around Jupiter and feels, as a result of its non-circular orbit, the periodically changing gravitational pull of the planet. The heat arising in Io's interior from this continual flexure makes it the most volcanically active body in the solar system, with more than 100 active volcanoes. The white and reddish colors on its surface are due to the presence of different sulfurous materials. The black areas are silicate rocks.Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  5. Report of the Ionosphere-Thermosphere-Mesosphere Panel

    Science.gov (United States)

    Szuszczewicz, Edward P.; Killeen, Tim L.; Arnoldy, Roger L.; Brace, Larry H.; Christensen, Andrew B.; Fejer, B.; Heelis, Roderick A.; Keskinen, Michael J.; Maynard, Nelson C.; Mayr, Hans G.

    1991-01-01

    The scientific objectives and mission concept that emerged from the discussions of this panel are presented. The overall scientific theme of this report is the investigation of the ionosphere, thermosphere, and mesosphere (near Earth space environment) as a global, dynamic, and coupled system. Among the specific goals of this area of research are: (1) understanding the consequences of transition between turbulent and laminar flow and collisional and collisionless media; (2) understanding the thermospheric/mesospheric coupling due to gravity wave, tidal, and trace constituent transport processes; (3) understanding the electrodynamical coupling between the thermosphere/ionosphere and magnetosphere; (4) understanding the coupling processes between small scale plasma structures; and (5) determining the real-time evolution of the global ionosphere electric field in response to solar wind and magnetosphere coupling.

  6. Broadband Linear Polarization of Jupiter Trojans

    CERN Document Server

    Bagnulo, S; Stinson, A; Christou, A; Borisov, G B

    2016-01-01

    Trojan asteroids orbit in the Lagrange points of the system Sun-planet-asteroid. Their dynamical stability make their physical properties important proxies for the early evolution of our solar system. To study their origin, we want to characterize the surfaces of Jupiter Trojan asteroids and check possible similarities with objects of the main belt and of the Kuiper Belt. We have obtained high-accuracy broad-band linear polarization measurements of six Jupiter Trojans of the L4 population and tried to estimate the main features of their polarimetric behaviour. We have compared the polarimetric properties of our targets among themselves, and with those of other atmosphere-less bodies of our solar system. Our sample show approximately homogeneous polarimetric behaviour, although some distinct features are found between them. In general, the polarimetric properties of Trojan asteroids are similar to those of D- and P-type main-belt asteroids. No sign of coma activity is detected in any of the observed objects. A...

  7. Temperature of the thermosphere. [Titan atmospheric model with energy transfer

    Science.gov (United States)

    Strobel, D. L.

    1974-01-01

    The vertical temperature contrast for the thermosphere of Titan is estimated considering heating by absorption of solar energy, energy loss through infrared radiation by polyatomic molecules, and energy transfer by thermal conduction between the regions of energy deposition and loss. Current observational data suggest a CH4/H2 mixing ratio of approximately greater than 1, and a vertical temperature contrast smaller than 10 K. However, it is highly probable that H2 and CH4 are not in equilibrium in the thermosphere if there are large H2 escape rates.

  8. Transfer function analysis of thermospheric perturbations

    Science.gov (United States)

    Mayr, H. G.; Harris, I.; Varosi, F.; Herrero, F. A.; Spencer, N. W.

    1986-01-01

    Applying perturbation theory, a spectral model in terms of vectors spherical harmonics (Legendre polynomials) is used to describe the short term thermospheric perturbations originating in the auroral regions. The source may be Joule heating, particle precipitation or ExB ion drift-momentum coupling. A multiconstituent atmosphere is considered, allowing for the collisional momentum exchange between species including Ar, O2, N2, O, He and H. The coupled equations of energy, mass and momentum conservation are solved simultaneously for the major species N2 and O. Applying homogeneous boundary conditions, the integration is carred out from the Earth's surface up to 700 km. In the analysis, the spherical harmonics are treated as eigenfunctions, assuming that the Earth's rotation (and prevailing circulation) do not significantly affect perturbations with periods which are typically much less than one day. Under these simplifying assumptions, and given a particular source distribution in the vertical, a two dimensional transfer function is constructed to describe the three dimensional response of the atmosphere. In the order of increasing horizontal wave numbers (order of polynomials), this transfer function reveals five components. To compile the transfer function, the numerical computations are very time consuming (about 100 hours on a VAX for one particular vertical source distribution). However, given the transfer function, the atmospheric response in space and time (using Fourier integral representation) can be constructed with a few seconds of a central processing unit. This model is applied in a case study of wind and temperature measurements on the Dynamics Explorer B, which show features characteristic of a ringlike excitation source in the auroral oval. The data can be interpreted as gravity waves which are focused (and amplified) in the polar region and then are reflected to propagate toward lower latitudes.

  9. High Latitude Mottling on Jupiter

    Science.gov (United States)

    2000-01-01

    The familiar banded appearance of Jupiter at low and middle latitudes gradually gives way to a more mottled appearance at high latitudes in this striking true color image taken Dec. 13, 2000, by NASA's Cassini spacecraft.The intricate structures seen in the polar region are clouds of different chemical composition, height and thickness. Clouds are organized by winds, and the mottled appearance in the polar regions suggests more vortex-type motion and winds of less vigor at higher latitudes.The cause of this difference is not understood. One possible contributor is that the horizontal component of the Coriolis force, which arises from the planet's rotation and is responsible for curving the trajectories of ocean currents and winds on Earth, has its greatest effect at high latitudes and vanishes at the equator. This tends to create small, intense vortices at high latitudes on Jupiter. Another possibility may lie in that fact that Jupiter overall emits nearly as much of its own heat as it absorbs from the Sun, and this internal heat flux is very likely greater at the poles. This condition could lead to enhanced convection at the poles and more vortex-type structures. Further analysis of Cassini images, including analysis of sequences taken over a span of time, should help us understand the cause of equator-to-pole differences in cloud organization and evolution.By the time this picture was taken, Cassini had reached close enough to Jupiter to allow the spacecraft to return images with more detail than what's possible with the planetary camera on NASA's Earth-orbiting Hubble Space Telescope. The resolution here is 114 kilometers (71 miles) per pixel. This contrast-enhanced, edge-sharpened frame was composited from images take at different wavelengths with Cassini's narrow-angle camera, from a distance of 19 million kilometers (11.8 million miles). The spacecraft was in almost a direct line between the Sun and Jupiter, so the solar illumination on Jupiter is almost full

  10. Effects of planetary-scale waves on temporal wind variations in the Venusian thermosphere

    Science.gov (United States)

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

    2008-12-01

    In recent years, the importance of planetary-scale waves for dynamics of the Venusian upper atmosphere has been recognized. For example, Forbes and Knopliv [2007] suggested propagations of planetary-scale waves originated in the cloud deck to the thermosphere from reanalysis of the Magellan spacecraft data. In addition, recent simulation studies suggest importance of tidal waves for the superrotation in the Venusian cloud deck [Takagi and Matsuda, 2007]. Venus Climate Orbiter (VCO), which will be launched in 2010 as the second Japanese planetary mission, is expected to provide precious information about upward propagating planetary scale-waves which can't be obtained by Venus Express because of the polar orbit and the close-up observations. In order to understand effects of the planetary-scale waves propagating from the cloud top on the thermospheric circulation, we have developed a new general circulation model (GCM) which includes about 80-200 km altitude region. The GCM solves the primitive equations for momentum, energy and composition. The solar EUV heating, NIR heating and 15μm Radiative cooling are considered. We also consider O, CO and CO2 as the major composition of the Venusian mesosphere and thermosphere. The horizontal and vertical resolutions are 10° in longitude, 20° in latitude, and 0.5 scale height in altitude, respectively. In this study, we perform GCM simulations with use of global distributions of planetary-scale waves taking into account the recent simulation results [e.g., Takagi and Matsuda, 2007] and the past observations [e.g., Del genio and Rossow, 1990]. We will also develop a method for GCM simulations with the VCO data.

  11. Measurements of Ion Drifts and Thermospheric Neutral Winds at the Jicamarca Radio Observatory

    Science.gov (United States)

    Meriwether, J. W.; Navarro, L.; Chau, J. L.; Fejer, B. G.

    2010-12-01

    Measurements of ion drifts and thermospheric neutral winds obtained simultaneously with zonal and vertical ion drift measurements of F-region plasma have been made at the Jicamarca Radio Observatory at different times during the year since August, 2009. This period is coincident with an anomalous period of extremely low solar activity. For campaigns taking place in September, 2009, March, 2010, and September, 2010, the Jicamarca 50 MHz radar operated to measure both vertical ion drifts and horizontal neutral winds from 200 to 800 km. The Jicamarca Fabry-Perot interferometer (FPI) was installed in August, 2009, and measurements have been ongoing since first light on 15 August, 2010. The FPI instrument is located in an observatory installed on a hill overlooking the Jicamarca valley and located above the cloud inversion layer, which improved the chances of observing during local summer. This instrument after an upgrade in August 2010 is able to make zonal and meridional thermospheric wind and temperature measurements with an accuracy of 5 to 10 ms-1 and 15 to 30 K. Also obtained during the measurement campaigns with the JRO radar facility were simultaneous measurements of thermospheric winds from the FPI observatory located in Arequipa, Peru, which is located 4 degrees latitude to the south of Jicamarca. The results obtained generally showed good agreement between the observed neutral winds and ion drifts. The vertical variation of the ion drifts is significant from the early evening twilight period to midnight suggesting that the transition from the E-region dynamo to the F-region dynamo takes place rather slowly as compared with more active solar flux periods.

  12. Equatorial thermospheric wind changes during the solar cycle: Measurements at Arequipa, Peru, from 1983 to 1990

    Energy Technology Data Exchange (ETDEWEB)

    Biondi, M.A. (Univ. of Pittsburgh, PA (United States)); Meriwether, J.W. Jr. (Air Force Geophysics Lab., Hanscom AFB, MA (United States)); Fejer, B.G.; Gonzalez, S.A. (Utah State Univ., Logan (United States)); Hallenbeck, D.C. (NASA Laser Tracking Station, Arequipa (Peru))

    1991-09-01

    Fabry-Perot interferometer measurements of Doppler shifts in the nightglow 630-nm emission line have been used to determine near-equatorial thermospheric wind velocities at Arequipa, Peru, over {approximately} 2/3 of a solar cycle. Monthly-average nocturnal variations in the meridional and zonal wind components were calculated from the nightly data to remove short term (day-to-day) variability, facilitating display of seasonal changes in the wind patterns, as well as any additional changes introduced by the progression of the solar cycle. The measured seasonal variations in the wind patterns are more pronounced than the solar cycle variations and are more readily understandable in terms of the expected, underlying forcing and damping processes. For most of the years, at the winter solstice, there is a weak ({le} 100 m/s) transequatorial flow from the summer to the winter hemisphere in the early and the late night, with essentially zero velocities in between. At the equinoxes, an early-night poleward (southward) flow at solar minimum (1986) is replaced by an equatorward (northward) flow at solar maximum (1989-1990). The zonal flows are predominantly eastward throughout the night, except for the solar minimum equinoxes, where brief westward flows appear in the early and the late night. The peak eastward velocities increase toward solar maximum; at the winter solstice, they are {approximately} 100-130 m/s in 1983, 1984 and 1986, reaching {approximately} 200 m/s in 1988, 1989 and 1990. The present equatorial thermospheric wind determinations agree in some respects with the satellite-data-based horizontal wind model IIWM-87 and the vector spherical harmonic form of the thermospheric general circulation model.

  13. High-latitude lower thermospheric neutral winds at EISCAT and Sondrestrom during LTCS 1

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.M. (Univ. of Michigan, Ann Arbor (USA)); Virdi, T.S. (Univ. Coll. of Wales, Aberystwyth (England))

    1991-02-01

    The incoherent scatter radar located at Soendre Stroemfjord, Greenland (67{degree}N, 51{degree}W, 74.5{degree}{Lambda}) and the EISCAT incoherent scatter facility located in northern Scandinavia (69.5{degree}N, 19{degree}E, 66.3{degree}{Lambda}) both obtained E and F region measurements during the first campaign of the Lower Thermosphere Coupling Study (LTCS 1, September 21-25, 1987). Neutral winds deduced from these measurements have been analyzed for their mean flow and tidal components. A number of the altitude profiles for the mean winds and the diurnal and semidiurnal wave components at the two radar locations show similar variations with height, indicating that latitudinal rather than longitudinal effects are dominant in determining the observed wind field. Diurnal tidal amplitudes and phases are reasonably well represented by theoretical model results (Forbes, 1982). The semidiurnal amplitudes and phases, although somewhat consistent between the two radars, are not well represented in equinox tidal model results (Forbes and Vial, this issue). Results from both radars indicate a vertical wavelength for the zonal semidiurnal oscillation of approximately 60 km. During a period of impulsive magnetospheric forcing (September 22-23), winds deduced from measurements at both radars show enhanced eastward flows near midnight accompanied by equatorward winds at Sondrestrom. Comparison with the results of a National Center for Atmospheric Research thermosphere-ionosphere general circulation model (TIGCM) simulation of the LTCS 1 interval shows generally better agreement with the observations at EISCAT than at Sondrestrom.

  14. A fireball in Jupiter's atmosphere

    Science.gov (United States)

    Cook, A. F.; Duxbury, T. C.

    1981-01-01

    One fireball was photographed during two encounters with Jupiter. Its total luminosity was 120,000 0 mag s (at standard range 100 km). If the luminous efficiency proposed by Cook et al. (1981) for slip flow of a meteoroid in its own vapors is employed, an estimated mass of 11 kg is obtained. A rough absolute magnitude is -12.5. If it is noted that the search was conducted for a total of 223 s during two exposures, a number density near Jupiter of 10 to the -28th/cu cm is estimated for masses of meteoroids of 3 kg and greater. This value is about a factor of six smaller than a rough upper limit reached from an extrapolation from terrestrial observations of meteors and comets.

  15. A Study of Jupiter Trojans

    OpenAIRE

    Karlsson, Ola

    2012-01-01

    Jupiter Trojan asteroid dynamics have been studied for a long time but it is only within the last decades that the known population has become large enough to make other studies meaningful. In four articles I have been scratching the surface of the unknown Trojan knowledge space. Paper I presents photometric observations confirming a larger variety in surface redness for the smaller Trojans compared to the larger ones, in line with the groups in the outer main asteroid belt. However, the larg...

  16. Quantification of Transient Changes of Thermospheric Neutral Density

    Science.gov (United States)

    2014-11-24

    Pedersen conductivity at high latitudes . Based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites...capture more random behavior of the electric field variability. The notable exception to this trend is EOF 11, which captures mid- latitude variations on...AFRL-OSR-VA-TR-2014-0320 Quantification of Transient Changes of Thermospheric Neutral Density Arthur Richmond UNIVERSITY CORPORATION FOR ATMOSPHERIC

  17. Strong thermospheric cooling during the 2009 major stratosphere warming

    NARCIS (Netherlands)

    Liu, H.; Doornbos, E.N.; Yamamoto, M.; Ram, S.T.

    2011-01-01

    Thermospheric density simultaneously observed by the CHAMP and GRACE satellites in both the pre‐dawn and afternoon local time sectors undergoes significant decrease across both hemispheres during the major stratospheric sudden warming (SSW) in January 2009. This decrease is largest in the equatorial

  18. A combined solar and geomagnetic index for thermospheric climate.

    Science.gov (United States)

    Mlynczak, Martin G; Hunt, Linda A; Marshall, B Thomas; Russell, James M; Mertens, Christopher J; Thompson, R Earl; Gordley, Larry L

    2015-05-28

    Infrared radiation from nitric oxide (NO) at 5.3 µm is a primary mechanism by which the thermosphere cools to space. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite has been measuring thermospheric cooling by NO for over 13 years. In this letter we show that the SABER time series of globally integrated infrared power (watts) radiated by NO can be replicated accurately by a multiple linear regression fit using the F10.7, Ap, and Dst indices. This allows reconstruction of the NO power time series back nearly 70 years with extant databases of these indices. The relative roles of solar ultraviolet and geomagnetic processes in determining the NO cooling are derived and shown to vary significantly over the solar cycle. The NO power is a fundamental integral constraint on the thermospheric climate, and the time series presented here can be used to test upper atmosphere models over seven different solar cycles.

  19. Strong thermospheric cooling during the 2009 major stratosphere warming

    NARCIS (Netherlands)

    Liu, H.; Doornbos, E.N.; Yamamoto, M.; Ram, S.T.

    2011-01-01

    Thermospheric density simultaneously observed by the CHAMP and GRACE satellites in both the pre‐dawn and afternoon local time sectors undergoes significant decrease across both hemispheres during the major stratospheric sudden warming (SSW) in January 2009. This decrease is largest in the equatorial

  20. Two Moons Meet over Jupiter

    Science.gov (United States)

    2007-01-01

    This beautiful image of the crescents of volcanic Io and more sedate Europa was snapped by New Horizons' color Multispectral Visual Imaging Camera (MVIC) at 10:34 UT on March 2, 2007, about two days after New Horizons made its closest approach to Jupiter. The picture was one of a handful of the Jupiter system that New Horizons took primarily for their artistic, rather than scientific value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter. This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. The night side of Io is illuminated here by light reflected from Jupiter, which is out of the frame to the right. Europa's night side is completely dark, in contrast to Io, because that side of Europa faces away from Jupiter. Here, Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) -high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are barely visible: one from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and one from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The plumes appear blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume. The images are centered at 1 degree north, 60 degrees west on Io, and 0 degrees north, 149 degrees west on Europa. The color in this image was generated using

  1. Juno at Jupiter: Mission and Science

    Science.gov (United States)

    Bolton, Scott

    2016-07-01

    The Juno mission is the second mission in NASA's New Frontiers program. Launched in August 2011, Juno arrives at Jupiter in July 2016. Juno science goals include the study of Jupiter's origin, interior structure, deep atmosphere, aurora and magnetosphere. Jupiter's formation is fundamental to the evolution of our solar system and to the distribution of volatiles early in the solar system's history. Juno's measurements of the abundance of Oxygen and Nitrogen in Jupiter's atmosphere, and the detailed maps of Jupiter's gravity and magnetic field structure will constrain theories of early planetary development. Juno's orbit around Jupiter is a polar elliptical orbit with perijove approximately 5000 km above the visible cloud tops. The payload consists of a set of microwave antennas for deep sounding, magnetometers, gravity radio science, low and high energy charged particle detectors, electric and magnetic field radio and plasma wave experiment, ultraviolet imaging spectrograph, infrared imager and a visible camera. The Juno design enables the first detailed investigation of Jupiter's interior structure, and deep atmosphere as well as the first in depth exploration of Jupiter's polar magnetosphere. The Juno mission design, science goals, and measurements related to the atmosphere of Jupiter will be presented.

  2. Global empirical wind model for the upper mesosphere/lower thermosphere. I. Prevailing wind

    Directory of Open Access Journals (Sweden)

    Y. I. Portnyagin

    Full Text Available An updated empirical climatic zonally averaged prevailing wind model for the upper mesosphere/lower thermosphere (70-110 km, extending from 80°N to 80°S is presented. The model is constructed from the fitting of monthly mean winds from meteor radar and MF radar measurements at more than 40 stations, well distributed over the globe. The height-latitude contour plots of monthly mean zonal and meridional winds for all months of the year, and of annual mean wind, amplitudes and phases of annual and semiannual harmonics of wind variations are analyzed to reveal the main features of the seasonal variation of the global wind structures in the Northern and Southern Hemispheres. Some results of comparison between the ground-based wind models and the space-based models are presented. It is shown that, with the exception of annual mean systematic bias between the zonal winds provided by the ground-based and space-based models, a good agreement between the models is observed. The possible origin of this bias is discussed.

    Key words: Meteorology and Atmospheric dynamics (general circulation; middle atmosphere dynamics; thermospheric dynamics

  3. Optical interferometric measurements of nighttime equatorial thermospheric winds at Arequipa, Peru

    Science.gov (United States)

    Meriwether, J. W., Jr.; Moody, J. W.; Biondi, M. A.; Roble, R. G.

    1986-01-01

    Nighttime measurements of equatorial thermospheric wind dynamics were obtained at Arequipa, Peru, with an automated field-widened Fabry-Perot interferometer between April 1983 and August 1983 and reduced data from 62 nights. Significant seasonal variations in both zonal and meridional components of the thermospheric neutral wind vector were observed. Near the equinox, between 2000 and 2300 LT, the zonal wind component is eastward with an amplitude between 100 and 150 m/s that gradually ebbs to zero by dawn. The meridional component is generally small throughout the night. In the winter months (May to August) and at the winter solstice, the zonal wind persists eastward throughout the night with speeds between 50 and 150 m/s. The meridional component is directed poleward (southward) toward the winter hemisphere with a speed of 50-75 m/s that decays to zero by midnight. Interferometric measurements of the 630.0-nm intensity at equinox showed a major reduction of the emission listing 1 or 2 hours in all directions but south shortly after evening twilight; this decrease was not observed during winter.

  4. Alfvén waves as a solar-interplanetary driver of the thermospheric disturbances.

    Science.gov (United States)

    Guo, Jianpeng; Wei, Fengsi; Feng, Xueshang; Liu, Huixin; Wan, Weixing; Yang, Zhiliang; Xu, Jiyao; Liu, Chaoxu

    2016-01-01

    Alfvén waves have been proposed as an important mechanism for the heating of the Sun's outer atmosphere and the acceleration of solar wind, but they are generally believed to have no significant impact on the Earth's upper atmosphere under quiet geomagnetic conditions due to their highly fluctuating nature of interplanetary magnetic field (i.e., intermittent southward magnetic field component). Here we report that a long-duration outward propagating Alfvén wave train carried by a high-speed stream produced continuous (~2 days) and strong (up to ± 40%) density disturbances in the Earth's thermosphere in a way by exciting multiple large-scale gravity waves in auroral regions. The observed ability of Alfvén waves to excite large-scale gravity waves, together with their proved ubiquity in the solar atmosphere and solar wind, suggests that Alfvén waves could be an important solar-interplanetary driver of the global thermospheric disturbances.

  5. Study of the thermospheric and ionospheric response to the 2009 sudden stratospheric warming using TIME-GCM and GSM TIP models: First results

    Science.gov (United States)

    Klimenko, M. V.; Klimenko, V. V.; Bessarab, F. S.; Korenkov, Yu N.; Liu, Hanli; Goncharenko, L. P.; Tolstikov, M. V.

    2015-09-01

    This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden stratospheric warming (SSW) event. This period was characterized by extremely low solar and geomagnetic activity. The study was performed using two first principal models: thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) and global self-consistent model of thermosphere, ionosphere, and protonosphere (GSM TIP). The stratospheric anomalies during SSW event were modeled by specifying the temperature and density perturbations at the lower boundary of the TIME-GCM (30 km altitude) according to data from European Centre for Medium-Range Weather Forecasts. Then TIME-GCM output at 80 km was used as lower boundary conditions for driving GSM TIP model runs. We compare models' results with ground-based ionospheric data at low latitudes obtained by GPS receivers in the American longitudinal sector. GSM TIP simulation predicts the occurrence of the quasi-wave vertical structure in neutral temperature disturbances at 80-200 km altitude, and the positive and negative disturbances in total electron content at low latitude during the 2009 SSW event. According to our model results the formation mechanisms of the low-latitude ionospheric response are the disturbances in the n(O)/n(N2) ratio and thermospheric wind. The change in zonal electric field is key mechanism driving the ionospheric response at low latitudes, but our model results do not completely reproduce the variability in zonal electric fields (vertical plasma drift) at low latitudes.

  6. Warm Jupiters Are Less Lonely than Hot Jupiters: Close Neighbors

    Science.gov (United States)

    Huang, Chelsea; Wu, Yanqin; Triaud, Amaury H. M. J.

    2016-07-01

    Exploiting the Kepler transit data, we uncover a dramatic distinction in the prevalence of sub-Jovian companions between systems that contain hot Jupiters (HJs) (periods inward of 10 days) and those that host warm Jupiters (WJs) (periods between 10 and 200 days). HJs, with the singular exception of WASP-47b, do not have any detectable inner or outer planetary companions (with periods inward of 50 days and sizes down to 2 R Earth). Restricting ourselves to inner companions, our limits reach down to 1 R Earth. In stark contrast, half of the WJs are closely flanked by small companions. Statistically, the companion fractions for hot and WJs are mutually exclusive, particularly in regard to inner companions. The high companion fraction of WJs also yields clues to their formation. The WJs that have close-by siblings should have low orbital eccentricities and low mutual inclinations. The orbital configurations of these systems are reminiscent of those of the low-mass close-in planetary systems abundantly discovered by the Kepler mission. This, and other arguments, lead us to propose that these WJs are formed in situ. There are indications that there may be a second population of WJs with different characteristics. In this picture, WASP-47b could be regarded as the extending tail of the in situ WJs into the HJ region and does not represent the generic formation route for HJs.

  7. Deuterated Methane and Ethane in the Atmosphere of Jupiter

    Science.gov (United States)

    Parkinson, C. D.; Yung, Y. L.; Lee, A. Y.; Crisp, D.

    2003-12-01

    CH3D and C2H5D are isotopic tracers in the deep Jovian atmosphere and susceptible to transport and chemical effects. It is expected that the tropospheric ([D]/[H])CH4 ratios determined from the various observations made should be relatively invariable, yet previous determinations of this quantity for Jupiter have given results inconsistent with experimental error bars. This suggests that there may be a problem with the interpretion of some of the observations, or that the apparent CH3D column abundance is variable. We report on the effects of varying important parameters over this pressure regime on the CH3D and C2H5D mixing ratios, CH3D and C2H5D fractionation, the ([D]/[H])CH4, ([D]/[H])C2H_6 and D/H (= ([D]/[H])H2) ratios and compare with the various CH3D and HD observations. Our results show that since the CH3D and C2H5D mixing ratios are strongly dependent upon K(z) in the region of interest where temporal or latitudinal variations in K(z) could significantly impact the measured ([D]/[H])CH4 ratio. The K(z) adopted represents complex upward convection and downdraft mixing that occurs in the Jovian atmosphere as evidenced by recent observations (Gierasch et al., 2000; Ingersoll et al., 2000; Roos-Serote et al., 2000; Vincent et al., 2000). Using our technique allows for the first time a way to explain the discrepancies in the ([D]/[H])CH4 ratio observations by offering a plausible link between the CH3D and C2H5D observations and upper tropospheric dynamical processes. In any case our calculations show how ([D]/[H])CH4 and ([D]/[H])C2H_6 can be used as a diagnostic tracer to constrain K(z) and to better understand the dynamics of the atmosphere in this pressure regime. Additionally, we have made calculations of the C2H5D in the thermosphere of Jupiter. The principal reactions determining the D abundance appear to be generation by reaction of H with vibrationally hot HD and loss by reaction of D with H2(v=0,1) and CH3. The H, CH3D and C2H5D distributions have

  8. Assessing the performance of thermospheric modelling with data assimilation throughout solar cycles 23 and 24

    CERN Document Server

    Murray, Sophie A; Jackson, David R; Bruinsma, Sean L

    2015-01-01

    Data assimilation procedures have been developed for thermospheric models using satellite density measurements as part of the EU Framework Package 7 ATMOP Project. Two models were studied; one a general circulation model, TIEGCM, and the other a semi-empirical drag temperature model, DTM. Results of runs using data assimilation with these models were compared with independent density observations from CHAMP and GRACE satellites throughout solar cycles 23 and 24. Time periods of 60 days were examined at solar minimum and maximum, including the 2003 Hallowe'en storms. The differences between the physical and the semi-empirical models have been characterised. Results indicate that both models tend to show similar behaviour; underestimating densities at solar maximum, and overestimating them at solar minimum. DTM performed better at solar minimum, with both models less accurate at solar maximum. A mean improvement of ~4% was found using data assimilation with TIEGCM. With further improvements, the use of general ...

  9. The Capture of Jupiter Trojans

    Science.gov (United States)

    Morbidelli, A.; Nesvorny, D.; Vokrouhlicky, D.

    2013-09-01

    The origin of Jupiter Trojans remained mysterious for decades. Particularly, it was difficult to explain the excitation of the inclinations of the Trojan population [1]. In 2005, Morbidelli et al. [2] proposed a scenario of capture from the trans-Neptunian disk, in the framework of the so-called "Nice model" [3,4]. This scenario explained in a natural way the observed orbital distribution of Trojans. The Nice model, however, evolved in the years, in order to satisfy an increasingly large number of constraints. It now appears that the dynamical evolution of the giant planets was different from that envisioned in [2]. Here, we assess again the process of capture of Trojans within this new evolution. We show that (6-8)×10 - 7 of the original trans-Neptunian planetesimals are captured in the Trojan region, with an orbital distribution consistent with the one observed. Relative to [2], the new capture mechanism has the potential of explaining the asymmetry between the L4 and L5 populations. Moreover, the resulting population of Trojans is consistent with that of the Irregular Satellites of Jupiter, which are captured in the same process; a few bodies from the main asteroid belt could also be captured in the Trojan cloud.

  10. Longitudinal Variations in Jupiter's Winds

    Science.gov (United States)

    Simon-Miller, Amy A.; Gierasch, P. J.; Tierney, G.

    2010-01-01

    Long-term studies of Jupiter's zonal wind field revealed temporal variations on the order of 20 to 40 m/s at many latitudes, greater than the typical data uncertainties of 1 to 10 m/s. No definitive periodicities were evident, however, though some latitudinally-confined signals did appear at periods relevant to the Quasi- Quadrennial Oscillation (Simon-Miller & Gierasch, Icarus, in press). As the QQO appears, from vertical temperature profiles, to propagate downward, it is unclear why a signal is not more obvious, unless other processes dominate over possibly weaker forcing from the QQO. An additional complication is that zonal wind profiles represent an average over some particular set of longitudes for an image pair and most data sets do not offer global wind coverage. Lien avoiding known features, such as the large anticyclonic vortices especially prevalent in the south, there can be distinct variations in longitude. We present results on the full wind field from Voyager and Cassini data, showing apparent longitudinal variations of up to 60 m/s or more. These are particularly obvious near disruptions such as the South Equatorial Disturbance, even when the feature itself is not clearly visible. These two dates represent very different states of the planet for comparison: Voyagers 1 & 2 flew by Jupiter shortly after a global upheaval, while many regions were in a disturbed state, while the Cassini view is typical of a more quiescent period present during much of the 1990s and early 2000s.

  11. Jupiter's magnetosphere and radiation belts

    Science.gov (United States)

    Kennel, C. F.; Coroniti, F. V.

    1979-01-01

    Radioastronomy and Pioneer data reveal the Jovian magnetosphere as a rotating magnetized source of relativistic particles and radio emission, comparable to astrophysical cosmic ray and radio sources, such as pulsars. According to Pioneer data, the magnetic field in the outer magnetosphere is radially extended into a highly time variable disk-shaped configuration which differs fundamentally from the earth's magnetosphere. The outer disk region, and the energetic particles confined in it, are modulated by Jupiter's 10 hr rotation period. The entire outer magnetosphere appears to change drastically on time scales of a few days to a week. In addition to its known modulation of the Jovian decametric radio bursts, Io was found to absorb some radiation belt particles and to accelerate others, and most importantly, to be a source of neutral atoms, and by inference, a heavy ion plasma which may significantly affect the hydrodynamic flow in the magnetosphere. Another important Pioneer finding is that the Jovian outer magnetosphere generates, or permits to escape, fluxes of relativistic electrons of such intensities that Jupiter may be regarded as the dominant source of 1 to 30 MeV cosmic ray electrons in the heliosphere.

  12. Atmospheric Escape from Hot Jupiters

    CERN Document Server

    Murray-Clay, Ruth; Murray, Norman

    2008-01-01

    Photoionization heating from UV radiation incident on the atmospheres of hot Jupiters may drive planetary mass loss. We construct a model of escape that includes realistic heating and cooling, ionization balance, tidal gravity, and pressure confinement by the host star wind. We show that mass loss takes the form of a hydrodynamic ("Parker") wind, emitted from the planet's dayside during lulls in the stellar wind. When dayside winds are suppressed by the confining action of the stellar wind, nightside winds might pick up if there is sufficient horizontal transport of heat. A hot Jupiter loses mass at maximum rates of ~2 x 10^12 g/s during its host star's pre-main-sequence phase and ~2 x10^10 g/s during the star's main sequence lifetime, for total maximum losses of ~0.06% and ~0.6% of the planet's mass, respectively. For UV fluxes F_UV < 10^4 erg/cm^2/s, the mass loss rate is approximately energy-limited and is proportional to F_UV^0.9. For larger UV fluxes, such as those typical of T Tauri stars, radiative ...

  13. Engineering a Solution to Jupiter Exploration

    Science.gov (United States)

    Clark, Karla; Magner, Thomas; Lisano, Michael; Pappalardo, Robert

    2010-01-01

    The Europa Jupiter System Mission (EJSM) would be an international mission with the overall theme of investigating the emergence of habitable worlds around gas giants. Its goals are to (1) explore Europa to investigate its habitability, (2) characterize Ganymede as a planetary object including its potential habitability and (3) explore the Jupiter system as an archetype for gas giants. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with conceptual orbiters developed by NASA and ESA. The baseline EJSM architecture consists of two primary elements operating simultaneously in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. EJSM would directly address themes concerning the origin and evolution of satellite systems and water-rich environments in icy satellites. The potential habitability of the ocean-bearing moons Europa and Ganymede would be investigated, by characterizing the geophysical, compositional, geological, and external processes that affect these icy worlds. EJSM would also investigate Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant planets and their satellites would be better known. Most importantly, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM baseline architecture would provide opportunities for coordinated synergistic observations by JEO and JGO of the Jupiter and Ganymede magnetospheres, the volcanoes and torus of Io, the atmosphere of Jupiter, and comparative planetology of icy satellites. Each spacecraft would conduct both synergistic dual-spacecraft investigations and stand

  14. On the global mean temperature of the thermosphere

    Science.gov (United States)

    Roble, R. G.; Emergy, B. A.

    1983-01-01

    It is pointed out that the global mean temperature structure of the thermosphere above 120 km is primarily maintained by the absorption of solar extreme ultraviolet (EUV) flux at wavelengths less than 1025 A and solar ultraviolet (UV) flux. A number of previous calculations of the global mean temperature profile have determined that it is not possible to obtain agreement between the calculated global mean exospheric temperature and observed values. Since those studies, a considerable amount of new information on this problem has been obtained, including data obtained with the aid of the Atmospheric Explorer satellites. The present investigation is, therefore, concerned with a reexamination of the question whether there is enough solar UV radiation and auroral energy input to maintain the observed global mean temperature structure of the thermosphere above 120 km. It is found that for solar cycle minimum conditions there is an approximate balance between absorbed solar radiation and downward molecular thermal conduction.

  15. Thermospheric neutral densities derived from Swarm accelerometer and GPS data

    DEFF Research Database (Denmark)

    Doornbos, Eelco; Encarnacao, Joao; van den IJss, Jose;

    approach, affects the possibility of determining densities from the accelerometer measurements of the Swarm A and B satellites. We also investigate the possibility of determining crosswind speeds from Swarm data.In the meantime, we have investigated the possibility of deriving thermosphere neutral density...... affected and most promising data for scientific use. The goal to make the Swarm C accelerometer along-track axis data ready for further processing into level 2 thermosphere density data has now been accomplished, with the help of information on the satellite motion from the GPS tracking as well...... data from the Swarm GPS observations only, with a much lower temporal resolution. We analyse the differences in the data between the three Swarm satellites as well as between the accelerometer-derived and GPS-only-derived densities for Swarm C....

  16. Numerical modelling of the thermosphere-ionosphere coupling during substorm

    Science.gov (United States)

    Korenkov, Yu. N.; Bessarab, F. S.; Klimenko, V. V.; Surotkin, V. A.; Smertin, V. M.

    The numerical calculation results of the thermospheric parameters ([O]/[N_2] ratio and Tn) and critical frequencies of F2-region of ionosphere, foF2, in the global scale for the recovery phase of the substorm are presented. The calculations were executed with the use of the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) was constructed in the Kaliningrad Observatory of the IZMIRAN and modified in the Polar Geophysical Institute. The influences of the global distribution of Joule dissipation on the neutral atmosphere and ionosphere parameters are discussed. It is emphasised that the Joule dissipation in the neutral atmosphere is a main cause of the negative disturbance in the F2 region of the ionosphere.

  17. Effects of 27-day averaged tidal forcing on the thermosphere-ionosphere as examined by the TIEGCM

    Science.gov (United States)

    Maute, A. I.; Forbes, J. M.; Hagan, M. E.

    2016-12-01

    The variability of the ionosphere and thermosphere is influenced by solar and geomagnetic forcing and by lower atmosphere coupling. During the last solar minimum low- and mid-latitude ionospheric observations have shown strong longitudinal signals which are associated with upward propagating tides. Progress has been made in explaining observed ionospheric and thermospheric variations by investigating possible coupling mechanisms e.g., wind dynamo, propagation of tides into the upper thermosphere, global circulation changes, and compositional effects. To fully understand the vertical coupling a comprehensive set of simultaneous measurements of key quantities is missing. The Ionospheric Connection (ICON) explorer will provide such a data set and the data interpretation will be supported by numerical modeling to investigate the lower to upper atmosphere coupling. Due to ICON's orbit, 27 days of measurements are needed to cover all longitudes and local times and to be able to derive tidal components. In this presentation we employ the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) to evaluate the influence of the 27-day processing window on the ionosphere and thermosphere state. Specifically, we compare TIEGCM simulations that are forced at its 97 km lower boundary by daily tidal fields from 2009 MERRA-forced TIME-GCM output [Häusler et al., 2015], and by the corresponding 27-day mean tidal fields. Apart from the expected reduced day-to-day variability when using 27-day averaged tidal forcing, the simulations indicate net NmF2 changes at low latitudes, which vary with season. First results indicate that compositional effects may influence the Nmf2 modifications. We will quantify the effect of using a 27-day averaged diurnal tidal forcing versus daily ones on the equatorial vertical drift, low and mid-latitude NmF2 and hmF2, global circulation, and composition. The possible causes for the simulated changes will be examined. The result of

  18. Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

    Science.gov (United States)

    Connor, Hyunju Kim; Zesta, Eftyhia; Fedrizzi, Mariangel; Shi, Yong; Raeder, Joachim; Codrescu, Mihail V.; Fuller-Rowell, Tim J.

    2016-06-01

    The magnetosphere is a major source of energy for the Earth's ionosphere and thermosphere (IT) system. Current IT models drive the upper atmosphere using empirically calculated magnetospheric energy input. Thus, they do not sufficiently capture the storm-time dynamics, particularly at high latitudes. To improve the prediction capability of IT models, a physics-based magnetospheric input is necessary. Here, we use the Open Global General Circulation Model (OpenGGCM) coupled with the Coupled Thermosphere Ionosphere Model (CTIM). OpenGGCM calculates a three-dimensional global magnetosphere and a two-dimensional high-latitude ionosphere by solving resistive magnetohydrodynamic (MHD) equations with solar wind input. CTIM calculates a global thermosphere and a high-latitude ionosphere in three dimensions using realistic magnetospheric inputs from the OpenGGCM. We investigate whether the coupled model improves the storm-time IT responses by simulating a geomagnetic storm that is preceded by a strong solar wind pressure front on August 24, 2005. We compare the OpenGGCM-CTIM results with low-earth-orbit satellite observations and with the model results of Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe). CTIPe is an up-to-date version of CTIM that incorporates more IT dynamics such as a low-latitude ionosphere and a plasmasphere, but uses empirical magnetospheric input. OpenGGCM-CTIM reproduces localized neutral density peaks at ~ 400 km altitude in the high-latitude dayside regions in agreement with in situ observations during the pressure shock and the early phase of the storm. Although CTIPe is in some sense a much superior model than CTIM, it misses these localized enhancements. Unlike the CTIPe empirical input models, OpenGGCM-CTIM more faithfully produces localized increases of both auroral precipitation and ionospheric electric fields near the high-latitude dayside region after the pressure shock and after the storm onset, which in turn

  19. Thermospheric zonal temperature gradients observed at low latitudes

    Directory of Open Access Journals (Sweden)

    P. R. Fagundes

    Full Text Available Fabry-Perot interferometer (FPI measurements of thermospheric temperatures from the Doppler widths of the OI 630 nm nightglow emission line have been carried out at Cachoeira Paulista (23° S, 45° W, 16° S dip latitude, Brazil. The east-west components of the thermospheric temperatures obtained on 73 nights during the period from 1988 to 1992, primarily under quiet geomagnetic conditions, were analyzed and are presented in this paper. It was observed that on 67% of these nights, the temperatures in both the east and west sectors presented similar values and nocturnal variations. However, during 33% of the nights, the observed temperatures in the west sector were usually higher than those observed in the east sector, with zonal temperature gradients in the range of 100 K to 600 K, over about an 800 km horizontal distance. Also, in some cases, the observed temperatures in the east and west sectors show different nocturnal variations. One of the possible sources considered for the observed zonal temperature gradients is the influence of gravity wave dissipation effects due to waves that propagate from lower altitudes to thermospheric heights. The observed zonal temperature gradients could also be produced by orographic gravity waves originated away, over the Andes Cordillera in the Pacific Sector, or by dissipation of orographic gravity waves generated over the Mantiqueira Mountains in the Atlantic sector by tropospheric disturbances (fronts and/or subtropical jet streams.

    Key words. Atmospheric composition and structure (air-glow and aurora; thermosphere - composition and chemistry Ionosphere (equatorial ionosphere

  20. Modeling the Thermosphere as a Driven-Dissipative Thermodynamic System

    Science.gov (United States)

    2013-03-01

    Schoendorf, K. D., Siebert, K. D., et al. “Hill Model of Transpolar Potential Saturation: Comparison with MHD Simulation,” Journal of Geophysical...March and 1 December, 2009, where the risk of collision with debris has forced the crew of the International Space Station to take emergency actions to...Solomon, S. C. “A Model of Nitric Oxide in the Lower Thermosphere,” Journal of Geophysical Research, 107: 1205 (2002). Borovsky, J. E., and Denton, M

  1. Comparing High-latitude Ionospheric and Thermospheric Lagrangian Coherent Structures

    Science.gov (United States)

    Wang, N.; Ramirez, U.; Flores, F.; Okic, D.; Datta-Barua, S.

    2015-12-01

    Lagrangian Coherent Structures (LCSs) are invisible boundaries in time varying flow fields that may be subject to mixing and turbulence. The LCS is defined by the local maxima of the finite time Lyapunov exponent (FTLE), a scalar field quantifying the degree of stretching of fluid elements over the flow domain. Although the thermosphere is dominated by neutral wind processes and the ionosphere is governed by plasma electrodynamics, we can compare the LCS in the two modeled flow fields to yield insight into transport and interaction processes in the high-latitude IT system. For obtaining thermospheric LCS, we use the Horizontal Wind Model 2014 (HWM14) [1] at a single altitude to generate the two-dimensional velocity field. The FTLE computation is applied to study the flow field of the neutral wind, and to visualize the forward-time Lagrangian Coherent Structures in the flow domain. The time-varying structures indicate a possible thermospheric LCS ridge in the auroral oval area. The results of a two-day run during a geomagnetically quiet period show that the structures are diurnally quasi-periodic, thus that solar radiation influences the neutral wind flow field. To find the LCS in the high-latitude ionospheric drifts, the Weimer 2001 [2] polar electric potential model and the International Geomagnetic Reference Field 11 [3] are used to compute the ExB drift flow field in ionosphere. As with the neutral winds, the Lagrangian Coherent Structures are obtained by applying the FTLE computation. The relationship between the thermospheric and ionospheric LCS is analyzed by comparing overlapping FTLE maps. Both a publicly available FTLE solver [4] and a custom-built FTLE computation are used and compared for validation [5]. Comparing the modeled IT LCSs on a quiet day with the modeled IT LCSs on a storm day indicates important factors on the structure and time evolution of the LCS.

  2. Stormtime dynamics of the global thermosphere and equatorial ionosphere

    Directory of Open Access Journals (Sweden)

    W. J. Burke

    2009-05-01

    Full Text Available During magnetic storms the development of equatorial plasma bubbles (EPBs and distributions of thermospheric densities are strongly influenced by the histories of imposed magnetospheric electric (εM fields. Periods of intense EPB activity driven by penetration εM fields in the main phase are followed by their worldwide absence during recovery. A new method is applied to estimate global thermospheric energy (Eth budgets from orbit-averaged densities measured by accelerometers on polar-orbiting satellites. During the main phase of storms Eth increases as long as the stormtime εM operates, then exponentially decays toward quiet-time values during early recovery. Some fraction of the energy deposited at high magnetic latitudes during the main phase propagates into the subauroral ionosphere-thermosphere where it affects chemical and azimuthal-wind dynamics well into recovery. We suggest a scenario wherein fossils of main phase activity inhibit full restoration of quiet-time dayside dynamos and pre-reversal enhancements of upward plasma drifts near dusk denying bottomside irregularities sufficient time to grow into EPBs.

  3. A Combined Solar and Geomagnetic Index for Thermospheric Climate

    Science.gov (United States)

    Hunt, Linda; Mlynczak, Marty

    2015-01-01

    Infrared radiation from nitric oxide (NO) at 5.3 Â is a primary mechanism by which the thermosphere cools to space. The SABER instrument on the NASA TIMED satellite has been measuring thermospheric cooling by NO for over 13 years. Physically, changes in NO emission are due to changes in temperature, atomic oxygen, and the NO density. These physical changes however are driven by changes in solar irradiance and changes in geomagnetic conditions. We show that the SABER time series of globally integrated infrared power (Watts) radiated by NO can be replicated accurately by a multiple linear regression fit using the F10.7, Ap, and Dst indices. This fit enables several fundamental properties of NO cooling to be determined as well as their variability with time, permitting reconstruction of the NO power time series back nearly 70 years with extant databases of these indices. The relative roles of solar ultraviolet and geomagnetic processes in determining the NO cooling are derived and shown to be solar cycle dependent. This reconstruction provides a long-term time series of an integral radiative constraint on thermospheric climate that can be used to test climate models.

  4. Thermospheric Response to Solar Wind Electric Field Fluctuations

    Science.gov (United States)

    Perlongo, N. J.; Ridley, A. J.

    2013-12-01

    The electron density of the thermosphere is of paramount importance for radio communications and drag on low altitude satellites, particularly during geomagnetic storms. Transient enhancements of ion velocities and subsequent density and temperature increases frequently occur as a result of storm-driven solar wind electric field fluctuations. Since the Earth's dipole magnetic field is tilted and offset from the center of the planet, significant asymmetries arise that alter the thermospheric response to energy input based upon the time of day of the disturbance. This study utilizes the Global Ionosphere-Thermosphere Model (GITM) to investigate this phenomenon by enhancing the convective electric field for one hour of the day in 22 different simulations. An additional baseline run was conducted with no IMF perturbation. Furthermore, four configurations of Earth's magnetic field were considered, Internal Geomagnetic Reference Field (IGRF), a perfect dipole, a dipole tilted by 10 degrees, and a tilted and offset dipole. These runs were conducted at equinox when the amount of sunlight falling on the different hemispheres is the same. Two additional runs were conducted at the solstices for comparison. It was found that the most geo-effective times are when the poles are pointed towards the sun. The electron density, neutral density and temperature as well as the winds are explored.

  5. Winds in the high-latitude lower thermosphere: Dependence on the interplanetary magnetic field

    DEFF Research Database (Denmark)

    Richmond, A.D.; Lathuillere, C.; Vennerstrøm, Susanne

    2003-01-01

    [1] Wind observations in the summertime lower thermosphere at high southern latitudes, measured by the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite, are statistically analyzed in magnetic coordinates and correlated with the interplanetary magnetic field (IMF......) to determine influences of IMF-dependent ionospheric convection on the winds. Effects are clearly detectable down to 105 km altitude. Above 125 km the wind patterns show considerable similarity with ionospheric convection patterns, and the speed of the averaged neutral wind in the polar cap often exceeds 300 m....../s. The correlation between the IMF B-z component and the diurnal harmonic of the winds is generally best when the IMF is averaged over the preceding 1-4.5 hours. The magnetic-zonal-mean zonal wind below 120 km correlates best with the IMF B-y component when the latter is averaged over approximately the preceding 20...

  6. Eligibility for statin therapy by the JUPITER trial criteria and subsequent mortality.

    Science.gov (United States)

    Cushman, Mary; McClure, Leslie A; Lakoski, Susan G; Jenny, Nancy S

    2010-01-01

    Justification for the Use of Statins in Primary Prevention: An Intervention Trial Using Rosuvastatin (JUPITER) reported reduced cardiovascular and all-cause mortality with statin treatment in patients with elevated C-reactive protein (CRP) and average cholesterol levels who were not eligible for lipid-lowering treatment on the basis of existing guidelines. The aim of this study was to determine the prevalence of eligibility and mortality in a general population sample on the basis of eligibility for statin treatment using the JUPITER criteria. The study group consisted of 30,229 participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort, an observational study of US African American and white participants aged > or =45 years, enrolled in their homes from 2003 to 2007 and followed biannually by telephone. Among 11,339 participants age eligible for JUPITER and without vascular diagnoses or using lipid-lowering treatment, 21% (n = 2,342) met JUPITER entry criteria. Compared with JUPITER participants, they had similar low-density lipoprotein cholesterol and CRP levels, were more often women, were more often black, had metabolic syndrome, and used aspirin for cardioprotection. Over 3.5 years of follow-up, the mortality rate in REGARDS participants eligible for JUPITER was 1.17 per 100 patient-years (95% confidence interval 0.94 to 1.42). Compared with those otherwise JUPITER eligible who had CRP levels or =2 mg/L had a multivariate-adjusted relative risk of 1.5 (95% confidence interval 1.1 to 2.2) for total mortality. In conclusion, 21% not otherwise eligible would be newly eligible for lipid lowering treatment on the basis of JUPITER trial eligibility.

  7. Strong Langmuir turbulence at Jupiter?

    Science.gov (United States)

    Cairns, Iver H.; Robinson, P. A.

    1992-01-01

    Langmuir wave packets with short scale lengths less than an approximately equal to 100 lambda e have been observed in Jupiter's foreshock. Theoretical constraints on the electric fields and scale sizes of collapsing wave packets are summarized, extended and placed in a form suitable for easy comparison with Voyager and Ulysses data. The published data are reviewed and possible instrumental underestimation of fields discussed. New upper limits for the fields of the published wave packets are estimated. Wave packets formed at the nucleation scale from the observed large-scale fields cannot collapse because they are disrupted before collapse occurs. The published wave packets are quantitatively inconsistent with strong turbulence collapse. Strict constraints exist for more intense wave packets to be able to collapse: E greater than or approximately equals to 1-8 mV/m for scales less than or approximately equal to 100 lambda e. Means for testing these conclusions using Voyager and Ulysses data are suggested.

  8. Overview of Juno Results at Jupiter

    Science.gov (United States)

    Bolton, Scott; Connerney, Jack; Levin, Steve

    2017-04-01

    Juno is the first mission to investigate Jupiter using a close polar orbit. The Juno science goals include the study of Jupiter interior composition and structure, deep atmosphere and its polar magnetosphere. All orbits have peri-jove at approximately 5000 km above Jupiter's visible cloud tops. The payload consists of a set of microwave antennas for deep sounding, magnetometers, gravity radio science, low and high energy charged particle detectors, plasma wave antennas, ultraviolet imaging spectrograph, infrared imager and spectrometer and a visible camera. The Juno mission design, an overview of the early science results from Juno, and a description of the collaborative Earth based campaign will be presented.

  9. Juno's first glimpse of Jupiter's complexity

    Science.gov (United States)

    Bolton, Scott; Levin, Steven; Bagenal, Fran

    2017-08-01

    Preliminary results from NASA's Juno mission are presented in this special issue of Geophysical Research Letters. The data were gathered by nine scientific instruments as the Juno spacecraft approached Jupiter on the dawn flank, was inserted into Jupiter orbit on 4 July 2016, and made the first polar passes close to the planet. The first results hint that Jupiter may not have a distinct core, indicate puzzling deep atmospheric convection, and reveal complex small-scale structure in the magnetic field and auroral processes that are distinctly different from those at Earth.

  10. New Views of Jupiter's Rings

    Science.gov (United States)

    Burns, J. A.

    1998-09-01

    Jupiter's rings are the archetype of ethereal planetary rings (very-low optical-depth bands containing micron-sized "dust"). As a result of much improved observations by Galileo (Ockert-Bell* -- most citations are et al. and Icarus in press* or this meeting) and Keck (de Pater*), we now understand the nature of such rings. The ring has three components: a 104 km-thick toroidal halo (1.4-1.7 RJ; normal optical depth t = 10-6), a thin main ring (1.7-1.8 RJ; t = 10-6), and a pair of exterior gossamer rings (1.8-3.5RJ; t = 10-7). The main ring has patchy ( 20-30 percent) brightness. The ring is reddish and its particles satisfy a -2.5 differential power-law size distribution. Because particle lifetimes are brief, the rings must be continually regenerated, by collisions into parent bodies, which may be unseen or may be the known small ring-moons (Thomas*, Simonelli). The gossamer ring seems to be collisional ejecta derived from the ring-moons Amalthea and Thebe, and evolving inward by Poynting-Robertson drag (Burns). The particles drift through many electromagnetic resonances, clustering around synchronous orbit, which produce jumps in the particles' inclinations (Hamilton). The main ring is probably debris from Adrastea and Metis, which orbit in the equatorial plane. The halo particles are driven vertically by electromagnetic forces, which may be resonant (Schaffer & Burns) or not (Horanyi & Cravens). When halo orbits become highly distorted, particles are lost into Jupiter. Similar faint rings may be attendant to all small, close-in satellites (Showalter).

  11. Phosphine absorption in the 5-micron window of Jupiter

    Science.gov (United States)

    Beer, R.; Taylor, F. W.

    1979-01-01

    Since the original suggestion by Gillett et al. (1969) it has generally been assumed that the region of partial transparency near 5 micron in Jupiter's atmosphere (the 5-micron window) is bounded by the nu sub 4 NH3 at 6.1 micron and the nu sub 3 CH4 band at 3.3 micron. New measurements of Jupiter and of laboratory phosphine (PH3) samples show that PH3 is a significant contributor to the continuum opacity in the window and in fact defines its short-wavelength limit. This has important implications for the use of 5-micron observations as a means to probe the deep atmospheric structure of Jupiter. The abundance of PH3 which results from a comparison of Jovian and laboratory spectra is about 3 to 5 cm-am. This is five to eight times less than that found by Larson et al. (1977) in the same spectral region, but is in good agreement with the result of Tokunaga et al. (1979) from 10-micron observations.

  12. Re-inflated Warm Jupiters Around Red Giants

    CERN Document Server

    Lopez, Eric D

    2015-01-01

    Since the discovery of the first transiting hot Jupiters, models have sought to explain the anomalously large radii of highly irradiated gas giants. We now know that the size of hot Jupiter radius anomalies scales strongly with a planet's level of irradiation and numerous models like tidal heating, ohmic dissipation, and thermal tides have since been developed to help explain these inflated radii. In general however, these models can be grouped into two broad categories: 1) models that directly inflate planetary radii by depositing a fraction of the incident irradiation into the interior and 2) models that simply slow a planet's radiative cooling allowing it to retain more heat from formation and thereby delay contraction. Here we present a new test to distinguish between these two classes of models. Gas giants orbiting at moderate orbital periods around post main sequence stars will experience enormous increases their irradiation as their host stars move up the sub-giant and red-giant branches. If hot Jupite...

  13. Evidence for two-dimensional turbulence proceses in the lower thermosphere

    Science.gov (United States)

    Larsen, M. F.

    2010-12-01

    A striking feature of chemical release trails in the lower thermosphere is the transition from turbulent flow to apparently laminar flow at the nominal turbopause height. The transition is very sharp, occurring over a vertical distance of a few hundred meters or less and is easily recognizable in the images. Detailed quantitative information about turbulence properties in the critical transition region is difficult to obtain. The chemical trails are one of the few sources of such information, although extracting information about turbulent energy dissipation rates and turbulent diffusion coefficients requires images with good time and angular resolution and is a time intensive analysis process. The number of such analyses is therefore limited, but the results consistently show direct evidence of anomalous diffusion over an altitude range that extends 10-15 km above the nominal turbopause, i.e., in an altitude range where the flow qualitatively appears to be laminar. Anomalous diffusion, in this case, refers to tracer expansion that is more rapid than expected from molecular diffusion alone. The region where the anomalous trail expansion is found is also characterized by large wind speeds that tend to maximize within that altitude range. The maximum winds generally exceed 80 m/s and are often in the 100 to 150 m/s range, as shown by a large database of more than 500 chemical release wind measurements obtained over an extended period at a variety of locations and local times. In addition, rapid transport of Space Shuttle exhaust products from low to high latitudes is also known to occur in the same altitude range, suggesting that the transport is effective over large scales. The observational evidence thus indicates that the lower thermosphere, in the altitude range between 100 and 115 km, is a region of enhanced anomalous transport that operates over a broad range of spatial scales, from a kilometer or less to the planetary scale. Evidence for two

  14. Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

    NARCIS (Netherlands)

    Häusler, K.; Hagan, M.E.; Forbes, J.M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

    2015-01-01

    In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosp

  15. Wave coupling between the lower and middle thermosphere as viewed from TIMED and GOCE

    NARCIS (Netherlands)

    Gasperini, F.; Forbes, J.M.; Doornbos, E.N.; Bruinsma, S.L.

    2015-01-01

    Vertical coupling between the lower and middle thermosphere due to the eastward propagating diurnal tide with zonal wave number 3 (DE3) and the 3.5 day ultra-fast Kelvin Wave (UFKW) is investigated using Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics-Sounding of the Atmosphere using B

  16. RE-INFLATED WARM JUPITERS AROUND RED GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Eric D. [Institute for Astronomy, Royal Observatory Edinburgh, University of Edinburgh, Blackford Hill, Edinburgh (United Kingdom); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2016-02-10

    Since the discovery of the first transiting hot Jupiters, models have sought to explain the anomalously large radii of highly irradiated gas giants. We now know that the size of hot Jupiter radius anomalies scales strongly with a planet's level of irradiation and numerous models like tidal heating, ohmic dissipation, and thermal tides have since been developed to help explain these inflated radii. In general, however, these models can be grouped into two broad categories: models that directly inflate planetary radii by depositing a fraction of the incident irradiation into the interior and models that simply slow a planet's radiative cooling, allowing it to retain more heat from formation and thereby delay contraction. Here we present a new test to distinguish between these two classes of models. Gas giants orbiting at moderate orbital periods around post-main-sequence stars will experience enormous increases to their irradiation as their host stars move up the sub-giant and red-giant branches. If hot Jupiter inflation works by depositing irradiation into the planet's deep interiors then planetary radii should increase in response to the increased irradiation. This means that otherwise non-inflated gas giants at moderate orbital periods of >10 days can re-inflate as their host stars evolve. Here we explore the circumstances that can lead to the creation of these “re-inflated” gas giants and examine how the existence or absence of such planets can be used to place unique constraints on the physics of the hot Jupiter inflation mechanism. Finally, we explore the prospects for detecting this potentially important undiscovered population of planets.

  17. Modeling Jupiter's Quasi Quadrennial Oscillation (QQO) with Wave Drag Parameterizations

    Science.gov (United States)

    Cosentino, Rick; Morales-Juberias, Raul; Greathouse, Thomas K.; Orton, Glenn S.

    2016-10-01

    The QQO in Jupiter's atmosphere was first discovered after 7.8 micron infrared observations spanning the 1980's and 1990's detected a temperature oscillation near 10 hPa (Orton et al. 1991, Science 252, 537, Leovy et. al. 1991, Nature 354, 380, Friedson 1999, Icarus 137, 34). New observations using the Texas Echelon cross-dispersed Echelle Spectrograph (TEXES), mounted on the NASA Infrared Telescope facility (IRTF), have been used to characterize a complete cycle of the QQO between January 2012 and January 2016 (Greathouse et al. 2016, DPS) . These new observations not only show the thermal oscillation at 10 hPa, but they also show that the QQO extends upwards in Jupiter's atmosphere to pressures as high as 0.4 hPa. We incorporated three different wave-drag parameterizations into the EPIC General Circulation Model (Dowling et al. 1998, Icarus 132, 221) to simulate the observed Jovian QQO temperature signatures as a function of latitude, pressure and time using results from the TEXES datasets as new constraints. Each parameterization produces unique results and offers insight into the spectra of waves that likely exist in Jupiter's atmosphere to force the QQO. High-frequency gravity waves produced from convection are extremely difficult to directly observe but likely contribute a significant portion to the QQO momentum budget. We use different models to simulate the effects of waves such as these, to indirectly explore their spectrum in Jupiter's atmosphere by varying their properties. The model temperature outputs show strong correlations to equatorial and mid-latitude temperature fields retrieved from the TEXES datasets at different epochs. Our results suggest the QQO phenomenon could be more than one alternating zonal jet that descends over time in response to Jovian atmospheric forcing (e.g. gravity waves from convection).Research funding provided by the NRAO Grote Reber Pre-Doctoral Fellowship. Computing resources include the NMT PELICAN cluster and the CISL

  18. Astronomers find distant planet like Jupiter

    CERN Multimedia

    2003-01-01

    Astronomers searching for planetary systems like our solar system have found a planet similar to Jupiter orbiting a nearby star similar to our Sun, about 90 light-years from Earth, according to researchers (1/2 page).

  19. Kepler constraints on planets near hot Jupiters

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Fabrycky, Daniel C.; /UC, Santa Cruz, Astron. Astrophys.; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Ford, Eric B.; /Florida U.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Rowe, Jason F.; /NASA, Ames; Welsh, William F.; /San Diego State U., Astron. Dept.; Borucki, William J.; /NASA, Ames; Boss, Alan P.; /Carnegie Inst., Wash., D.C., DTM; Ciardi, David R.; /Caltech /Harvard-Smithsonian Ctr. Astrophys.

    2012-05-01

    We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2:1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.

  20. Kepler constraints on planets near hot Jupiters

    CERN Document Server

    Steffen, Jason H; Fabrycky, Daniel C; Carter, Joshua A; Ford, Eric B; Holman, Matthew J; Rowe, Jason F; Welsh, William F; Borucki, William J; Boss, Alan P; Ciardi, David R; Quinn, Samuel N

    2012-01-01

    We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 days) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2:1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly 2/3 to 5 times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations or TTVs) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.

  1. Far infrared spectrophotometry of Jupiter and Saturn

    Science.gov (United States)

    Erickson, E. F.; Goorvitch, D.; Simpson, J. P.; Strecker, D. W.

    1978-01-01

    Infrared spectral measurements of Mars, Jupiter, and Saturn were obtained from 100 to 470 kaysers and, by taking Mars as a calibration source, brightness temperatures of Jupiter and Saturn were determined with approximately 5 kayser resolution. Internal luminosities were determined from the data and are reported to be approximately 8 times 10 to the minus tenth power of the sun's luminosity for Jupiter and approximately 3.6 times 10 to the minus tenth power of the sun's luminosity for Saturn. Comparison of data with spectra predicted by models suggests the need for an opacity source in addition to gaseous hydrogen and ammonia to help explain Jupiter's observed spectrum in the vicinity of 250 kaysers.

  2. Jupiter Great Red Spot and White Ovals

    Science.gov (United States)

    1979-01-01

    This photo of Jupiter was taken by Voyager 1 on March 1, 1979. The spacecraft was 3 million miles (5 million kilometers) from Jupiter at the time. The photo shows Jupiter's Great Red Spot (upper right) and the turbulent region immediately to the west. At the middle right of the frame is one of several white ovals seen on Jupiter from Earth. The structure in every feature here is far better than has ever been seen from any telescopic observations. The Red Spot and the white oval both reveal intricate and involved structure. The smallest details that can be seen in this photo are about 55 miles (95 kilometers) across. JPL manages and controls the Voyager project for NASA's Office of Space Science.

  3. Tidal Response of Preliminary Jupiter Model

    CERN Document Server

    Wahl, Sean M; Militzer, Burkhard

    2016-01-01

    In anticipation of improved observational data for Jupiter's gravitational field from the Juno spacecraft, we predict the static tidal response for a variety of Jupiter interior models based on ab initio computer simulations of hydrogen-helium mixtures. We calculate hydrostatic-equilibrium gravity terms using the non-perturbative concentric Maclaurin Spheroid (CMS) method that eliminates lengthy expansions used in the theory of figures. Our method captures terms arising from the coupled tidal and rotational perturbations, which we find to be important for a rapidly-rotating planet like Jupiter. Our predicted static tidal Love number $k_2 = 0.5900$ is $\\sim$10\\% larger than previous estimates. The value is, as expected, highly correlated with the zonal harmonic coefficient $J_2$, and is thus nearly constant when plausible changes are made to interior structure while holding $J_2$ fixed at the observed value. We note that the predicted static $k_2$ might change due to Jupiter's dynamical response to the Galilea...

  4. Kepler constraints on planets near hot Jupiters.

    Science.gov (United States)

    Steffen, Jason H; Ragozzine, Darin; Fabrycky, Daniel C; Carter, Joshua A; Ford, Eric B; Holman, Matthew J; Rowe, Jason F; Welsh, William F; Borucki, William J; Boss, Alan P; Ciardi, David R; Quinn, Samuel N

    2012-05-22

    We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 21 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.

  5. Voyager-Jupiter radio science data papers

    Science.gov (United States)

    Levy, G. S.; Wood, G. E.

    1980-01-01

    The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

  6. Jupiter's Radiation Belts: Can Pioneer 10 Survive?

    Science.gov (United States)

    Hess, W N; Birmingham, T J; Mead, G D

    1973-12-07

    Model calculations of Jupiter's electron and proton radiation belts indicate that the Galilean satellites can reduce particle fluxes in certain regions of the inner magnetosphere by as much as six orders of magnitude. Average fluxes should be reduced by a factor of 100 or more along the Pioneer 10 trajectory through the heart of Jupiter's radiation belts in early December. This may be enough to prevent serious radiation damage to the spacecraft.

  7. Tidal Response of Preliminary Jupiter Model

    OpenAIRE

    Wahl, Sean M; Hubbard, Willam B.; Militzer, Burkhard

    2016-01-01

    In anticipation of improved observational data for Jupiter's gravitational field from the Juno spacecraft, we predict the static tidal response for a variety of Jupiter interior models based on ab initio computer simulations of hydrogen-helium mixtures. We calculate hydrostatic-equilibrium gravity terms using the non-perturbative concentric Maclaurin Spheroid (CMS) method that eliminates lengthy expansions used in the theory of figures. Our method captures terms arising from the coupled tidal...

  8. Hot-Jupiter Breakfasts Realign Stars

    Science.gov (United States)

    Kohler, Susanna

    2015-08-01

    Two researchers at the University of Chicago have recently developed a new theory to explain an apparent dichotomy in the orbits of planets around cool vs. hot stars. Their model proposes that the spins of cool stars are affected when they ingest hot Jupiters (HJs) early in their stellar lifetimes. A Puzzling Dichotomy: In exoplanet studies, there is a puzzling difference observed between planet orbits around cool and hot (those with Teff ≥ 6250 K) stars: the orbital planes of planets around cool stars are primarily aligned with the host star's spin, whereas the orbital planes of planets around hot stars seem to be randomly distributed. Previous attempts to explain this dichotomy have focused on tidal interactions between the host star and the planets observed in the system. Now Titos Matsakos and Arieh Königl have taken these models a step further — by including in their calculations not only the effects of observed planets, but also those of HJs that may have been swallowed by the star long before we observed the systems. Modeling Meals: Plots of the distribution of the obliquity λ for hot Jupiters around cool hosts (upper plot) and hot hosts (lower plot). The dashed line shows the initial distribution, the bins show the model prediction for the final distribution after the systems evolve, and the black dots show the current observational data. [Matsakos & Königl, 2015]" class="size-thumbnail wp-image-223" height="386" src="http://aasnova.org/wp-content/uploads/2015/08/fig22-260x386.png" width="260" /> Plots of the distribution of the obliquity λ for hot Jupiters around cool hosts (upper plot) and hot hosts (lower plot). The dashed line shows the initial distribution, the bins show the model prediction for the final distribution after the systems evolve, and the black dots show the current observational data. [Matsakos & Königl, 2015] The authors' model assumes that as HJs are formed and migrate inward through the protoplanetary disk, they stall out near

  9. Lasers and the Dynamic Mesosphere/Thermosphere of Venus

    Science.gov (United States)

    Kostiuk, Theodor; Fast, Kelly E.; Livengood, Timothy A.; Schmuelling, Frank; Hewagama, Tilak; Annen, John; Buhl, David; Sonnabend, Guido; Sornig, Manuela; Kroetz, Peter; Goldstein, Jeffrey

    2010-01-01

    A review of ground based mid-infrared uniquely high spectral. resolution measurements of Venus dynamics, temperature, and chemistry will be presented. The described studies will focus on the use of CO2 absorption features and the discovery- and use of CO2 thermospheric non-thermal emission: lines as probes of Venus' atmosphere, from the cloud tops to approx.120 km in the thermosphere. The first investigations using infrared heterodyne spectroscopy with resolving power lambda/Delta(lambda) approx. 10(exp 6) to measure true emission line profiles and to determine their non-thermal nature and lasing component will be described. The use of the thermospheric non-thermal CO2 emission to directly measure sub-solar to anti-solar winds and zonal circulation near 110 km altitudes on Venus to approx.2 m/s accuracy will also be described. The measured emission lures are also used to obtain global maps of mesospheric/thermospheric kinetic and rotational temperatures as well as to obtain evidence of the natural lasing phenomena. Carbon dioxide absorption features globally probe lower altitudes in the atmosphere and can be used to determine nightside temperatures. Isotopic 13 CO2 absorption lines are used to probe deeper in the atmosphere to measure the sub-solar to anti-solar return flow at altitudes just above the cloud tops. These results provided a model for global circulation in the 65 - 120 km altitude region first proposed by Goldstein (1989, PhD.Thesis, U. Pennsylvania, Philadelphia, USA). Results of similar wind and temperature measurements made in recent years will be compared to earlier results to investigate changes in the circulation and temperatures since approx.1990. The high resolution infrared heterodyne technique was also used to investigate chemical processes above the cloud tops, specifically evidence and constraints on oxygen-based chemistry. Described measurements were made by infrared heterodyne spectroscopy using the Goddard Space Flight Center Infrared

  10. Apparent Detection of Global Anthropogenic Effects Extending Into the Thermosphere

    Science.gov (United States)

    Keating, G. M.; Theriot, M. E.; Akmaev, R. A.; Bougher, S. W.

    2004-05-01

    From a study of long-term orbital decay of Earth satellites, it has been discovered that thermospheric densities have declined substantially since at least 1976. Detection of this decline was first published by Keating et al (2000) in Geophysical Research Letters. They performed an analysis of 5 Earth satellites with periapsis altitudes near 380 km. The study was conducted for conditions near solar minimum to remove the effect of the 11-year solar cycle. Comparisons were made with a standard empirical density model to remove the effects of variations in solar and geomagnetic activity, altitude, season, latitude, time of day, etc. In that article, it was proposed that the cooling trend was caused by anthropogenic effects. Now the data set has been expanded to 14 satellites near 380 km to obtain an improved estimate of the trend and to establish possible variations in the trend. In the new study, the average trend from 1976-1996 is found to be minus 10.3 plus or minus 1.2 percent. This is in accord with the 2000 paper, which gave an average trend of minus 9.8 plus or minus 2.5 percent. The new results show statistically insignificant differences between the trend at low and high latitudes indicating a global response with no significant correlation to geomagnetic activity variations. The results appear to be in accord with theoretical model estimates for the response of the thermosphere to increases in CO2 and CH4 predicted by Roble and Dickinson (1989), Rishbeth and Roble (1992), and Akmaev and Formichev (2000). A paper by Emmert et al (2004) using a similar approach of studying the orbital decay from 27 satellites qualitatively confirms the downward trend originally discovered in the 2000 paper. All 27 of the satellites they studied indicated a downward trend. Twenty of the 27 satellites experienced a decrease in thermospheric density at somewhat higher altitudes, between 500 and 700 km. It is estimated that CO2 will double before the end of this century

  11. Neutral thermospheric temperature from ion concentration measurements

    Science.gov (United States)

    Breig, E. L.; Donaldson, J. S.; Hanson, W. B.; Hoffman, J. H.; Power, R. A.; Kayser, D. C.; Spencer, N. W.; Wharton, L. E.

    1981-01-01

    A technique for extracting information on neutral temperature from in situ F region measurements of O(+) and H(+) ion concentrations is analyzed and evaluated. Advantage is taken of the condition of charge-exchange equilibrium of these species in the neighborhood of 320 km to infer the associated relative abundances of neutral oxygen and hydrogen. Results are shown to be generally consistent with other concurrent in situ measurements.

  12. Using Jupiter's Synchrotron Radiation as a Probe into Jupiter's Inner Radiation Belts

    Science.gov (United States)

    Bolton, S. J.; Gulkis, S.; Klein, M. J.; Thorne, R. M.

    1995-01-01

    The Jovian decimetric emission is caused by the combined emission of synchrotron radiation originating from the relativistic electrons trapped in Jupiter's 'Van Allen radiation belts' and thermal emission from the planet's atmosphere. Synchrotron radiation characteristics and variations (which provides insight into the physical properties of Jupiter's inner radiation belts) will be amplified and discussed.

  13. Temporal Variations in Jupiter's Atmosphere

    Science.gov (United States)

    Simon-Miller, Amy A.; Chanover, N. J.; Yanamandra-Fisher, P.; Hammel, H. B.; dePater, I.; Noll, K.; Wong, M.; Clarke, J.; Sanchez-Levega, A.; Orton, G. S.; Gonzaga, S.

    2009-01-01

    In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.

  14. The possible contamination of Jupiter

    Science.gov (United States)

    Garcia, Joe

    1988-01-01

    The Galileo probe, though at present its future is uncertain, would, if not sterilized, represent a good chance of contaminating Jupiter. Most scientists opposed to sterilizing the probe argue that to order the probe sterilized would be the death of the project, since sterilization would entail a reconstruction of the probe, and there are not enough funds to accomplish this. These scientists, however, are ignoring a relatively simple and inexpensive alternative to the traditional heat sterilization method. The main threat of contamination comes from Galileo's exterior surfaces: the shell of the probe and its parachute. The probe innermost components would not represent a threat since the probe is sealed. In light of the fact that only the exterior of Galileo would have to be sterilized, heat would not have to be used as a method of sterilization. Instead, various gas mixtures could be sprayed entirely over the probe and its parachute, gases which would kill any and all bacteria. This idea is more thoroughly examined.

  15. Hot Jupiters and cool stars

    Energy Technology Data Exchange (ETDEWEB)

    Villaver, Eva; Mustill, Alexander J. [Department of Theoretical Physics, Universidad Autónoma de Madrid, Módulo 8, 28049 Madrid (Spain); Livio, Mario [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Siess, Lionel, E-mail: eva.villaver@uam.es [Institut d' Astronomie et d' Astrophysique, Université Libre de Bruxelles, B-1050 Bruxelles (Belgium)

    2014-10-10

    Close-in planets are in jeopardy, as their host stars evolve off the main sequence (MS) to the subgiant and red giant phases. In this paper, we explore the influences of the stellar mass (in the range 1.5-2 M {sub ☉}), mass-loss prescription, planet mass (from Neptune up to 10 Jupiter masses), and eccentricity on the orbital evolution of planets as their parent stars evolve to become subgiants and red giants. We find that planet engulfment along the red giant branch is not very sensitive to the stellar mass or mass-loss rates adopted in the calculations, but quite sensitive to the planetary mass. The range of initial separations for planet engulfment increases with decreasing mass-loss rates or stellar masses and increasing planetary masses. Regarding the planet's orbital eccentricity, we find that as the star evolves into the red giant phase, stellar tides start to dominate over planetary tides. As a consequence, a transient population of moderately eccentric close-in Jovian planets is created that otherwise would have been expected to be absent from MS stars. We find that very eccentric and distant planets do not experience much eccentricity decay, and that planet engulfment is primarily determined by the pericenter distance and the maximum stellar radius.

  16. New results on equatorial thermospheric winds and temperatures from Ethiopia, Africa

    Science.gov (United States)

    Tesema, Fasil; Mesquita, Rafael; Meriwether, John; Damtie, Baylie; Nigussie, Melessew; Makela, Jonathan; Fisher, Daniel; Harding, Brian; Yizengaw, Endawoke; Sanders, Samuel

    2017-03-01

    Measurements of equatorial thermospheric winds, temperatures, and 630 nm relative intensities were obtained using an imaging Fabry-Perot interferometer (FPI), which was recently deployed at Bahir Dar University in Ethiopia (11.6° N, 37.4° E, 3.7° N magnetic). The results obtained in this study cover 6 months (53 nights of useable data) between November 2015 and April 2016. The monthly-averaged values, which include local winter and equinox seasons, show the magnitude of the maximum monthly-averaged zonal wind is typically within the range of 70 to 90 ms-1 and is eastward between 19:00 and 21:00 LT. Compared to prior studies of the equatorial thermospheric wind for this local time period, the magnitude is considerably weaker as compared to the maximum zonal wind speed observed in the Peruvian sector but comparable to Brazilian FPI results. During the early evening, the meridional wind speeds are 30 to 50 ms-1 poleward during the winter months and 10 to 25 ms-1 equatorward in the equinox months. The direction of the poleward wind during the winter months is believed to be mainly caused by the existence of the interhemispheric wind flow from the summer to winter hemispheres. An equatorial wind surge is observed later in the evening and is shifted to later local times during the winter months and to earlier local times during the equinox months. Significant night-to-night variations are also observed in the maximum speed of both zonal and meridional winds. The temperature observations show the midnight temperature maximum (MTM) to be generally present between 00:30 and 02:00 LT. The amplitude of the MTM was ˜ 110 K in January 2016 with values smaller than this in the other months. The local time difference between the appearance of the MTM and a pre-midnight equatorial wind was generally 60 to 180 min. A meridional wind reversal was also observed after the appearance of the MTM (after 02:00 LT). Climatological models, HWM14 and MSIS-00, were compared to the

  17. Multi-Periodic Auroral and Thermospheric Variations in 2006

    Directory of Open Access Journals (Sweden)

    Yongliang Zhang

    2013-01-01

    Full Text Available A data survey reveals multiple periodic variations in auroral hemispheric power (HP and thermospheric composition (O/N2 in 2006. The periods include 27, 13 - 14, 9, and 6.7 days. These periods of 13 - 14, 9 and 6.7 days are essentially the harmonics of the 27-day solar rotation. Similar multi-periodicities were found in the dayside magnetic merging rate (MMR (Newell et al. 2007 which depends upon solar wind speed (V, magnitude (BT and clock angle (θc of interplanetary magnetic field (IMF. A high correlation coefficient (0.93 between MMR and HP indicates MMR is the driver of the periodic variations. While high solar wind speed associated with coronal holes plays an important role in the HP variations, IMF BT is equally important. The term [BT2/3sin8/3(θc/2] is even more important as its correlation coefficient with HP is higher than that for BT or solar wind speed. Nevertheless, MMR has the highest correlation with HP. Similar results were seen in the 2005 data where the 9-day variation is dominant. These results indicate that both solar wind speed and IMF conditions are required for accurate specification of periodic variations in aurora hemispheric power and thermosphere composition.

  18. A 'Moving' Jupiter Global Map (Animation)

    Science.gov (United States)

    2007-01-01

    The Long Range Reconnaissance Imager (LORRI) on New Horizons has acquired six global maps of Jupiter as the spacecraft approaches the giant planet for a close encounter at the end of February. The high-resolution camera acquired each of six observation 'sets' as a series of individual pictures taken one hour apart, covering a full 10-hour rotation of Jupiter. The LORRI team at the Johns Hopkins University Applied Physics Laboratory (APL) reduced the sets to form six individual maps in a simple rectangular projection. These six maps were then combined to make the movie. The table below shows the dates and the ranges from Jupiter at which these six sets of observations were acquired. Even for the latest set of images taken January 21-22, from 60.5 million kilometers (37.6 million miles), New Horizons was still farther from Jupiter than the average distance of Mercury from the Sun. At that distance from Jupiter, a single LORRI picture resolution element amounts to 300 kilometers (186 miles) on Jupiter. Many features seen in Jupiter's atmosphere are giant storm clouds. The Little Red Spot, which LORRI will image close-up on February 27, is the target-like feature located near 30 degrees South and 230 degrees West; this storm is larger than the Earth. The even larger Great Red Spot is seen near 20 degrees South and 320 degrees West. The counterclockwise rotation of the clouds within the Great Red Spot can be seen. The westward drift of the Great Red Spot is easily seen in the movie, as is the slower drift, in the opposite direction, of the Little Red Spot. The storms of Jupiter are not fixed in location relative to each other or relative to any solid surface below, because Jupiter is a fluid planet without a solid surface. Also, dramatic changes are seen in the series of bright plume-like clouds encircling the planet between 0 and 10 degrees North. Scientists believe these result from an enormous atmospheric wave with rising air, rich in ammonia that condenses to form

  19. Seasonal variations in the equatorial thermospheric wind measured at Arequipa, Peru

    Energy Technology Data Exchange (ETDEWEB)

    Biondi, M.A.; Merriwether, J.W.; Fejer, B.G.; Gonzalez, S.A.

    1990-08-01

    Studies have been carried out Arequipa, Peru, of the seasonal variations in the thermospheric winds at moderate solar flux levels and geomagnetic activity. Fabry-Perot interferometer measurements of the doppler shifts in the 630.0 nm nightglow emission line from March to August 1983 and from April to October 1988 have yielded monthly-average meridional winds that are nearly zero (<50 m/s) and possible fluctuating in direction through much of the night but develop a southward flow at 50 - 100 m/s in the early and the late night from May onward. The average zonal winds are eastward throughout the night, reaching peak velocities before local midnight and then decreasing. The peak velocities increase to a maximum around the June solstice. The winds are generally stronger in 1988 than in 1983, even thought the solar EUV fluxes are comparable fro both years. Comparison of the present results with earlier satellite measurements, as embodied in the Horizontal Wind Model of Hedin et al., reveals generally satisfactory agreement at the equinox and June solstice, except for the June 1988 period. NCAR Therospheric General Circulation Model, calculated for similar solar flux levels, yields meridional and zonal wind variations which exhibit the same temporal behaviors but generally smaller values than the present measurements.

  20. Transient internally driven aurora at Jupiter discovered by Hisaki and the Hubble Space Telescope

    Science.gov (United States)

    Kimura, T.; Badman, S. V.; Tao, C.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Tsuchiya, F.; Bonfond, B.; Steffl, A. J.; Masters, A.; Kasahara, S.; Hasegawa, H.; Yoshikawa, I.; Fujimoto, M.; Clarke, J. T.

    2015-03-01

    Jupiter's auroral emissions reveal energy transport and dissipation through the planet's giant magnetosphere. While the main auroral emission is internally driven by planetary rotation in the steady state, transient brightenings are generally thought to be triggered by compression by the external solar wind. Here we present evidence provided by the new Hisaki spacecraft and the Hubble Space Telescope that shows that such brightening of Jupiter's aurora can in fact be internally driven. The brightening has an excess power up to ~550 GW. Intense emission appears from the polar cap region down to latitudes around Io's footprint aurora, suggesting a rapid energy input into the polar region by the internal plasma circulation process.

  1. Lower thermosphere coupling study: Comparison of observations with predictions of the University College London-Sheffield thermosphere-ionosphere model

    Energy Technology Data Exchange (ETDEWEB)

    Fuller-Rowell, T.J.; Rees, D.; Parish, H.F. (Univ. Coll. London (England)); Virdi, T.S.; Williams, P.J.S. (Univ. Coll. of Wales, Aberystwyth (England)); Johnson, R.M. (Univ. of Michigan, Ann Arbor (USA))

    1991-02-01

    During the first Lower Thermosphere Coupling Study (LTCS), September 21-25 1987, data were recorded from the incoherent scatter radar sites at EISCAT, Millstone Hill, Sondrestrom, and Arecibo. These experimental facilities measured ionospheric parameters (Ne, Te, Ti, and plasma velocity) in the E and the F regions which have been used to determine the E region neutral wind and infer the neutral temperature in the height range 100-150 km. Propagating tides are clearly visible in some of the parameters, and the latitude structure and phase variations with height indicate the presence of at least the (2,2) and (2,4) global tidal Hough modes. The influence of geomagnetic forcing is also clearly present at high latitudes. The University College London-Sheffield University three-dimensional coupled thermosphere-ionosphere model has been used to simulate this period of observation, by imposing tidal forcing at the lower boundary and magnetospheric forcing at high latitudes, in an attempt to interpret and understand the experimental data. Model simulations are able to predict where the signature of a particular tidal mode is likely to be observed in the respective responses of the temperature and wind structure. The numerical simulations predict the range of observed tidal amplitudes at mid and high latitudes, provided the tidal forcing functions imposed near the lower boundary of the model are larger (400 m geopotential height variation) than those inferred from linear tidal models.

  2. Detection and analysis of Jupiter's decametric micropulses

    Science.gov (United States)

    Lebo, G. R.

    1972-01-01

    The occurrence of Jupiter's decametric radio emission can be correlated with the central meridian longitude of Jupiter as if the active regions were radio transmitters placed at fixed longitudes on its surface. These active regions are commonly called sources and are labelled Source A, Jovian longitude = 200 deg, Source B = 100 deg and Source C =300 deg. These sources are not always active. However, they can be turned-on if Jupiter's innermost Galilean moon, Io, is in the right phase. In fact, if Io is found 90 deg from superior geocentric conjunction (maximum eastern elongation) and if source B is simultaneously on the central meridian, source B radiation is almost guaranteed, whereas source C radiation is highly likely when Io is found 240 deg from superior geocentric conjunction. Source A radiation is largely independent of Io's position. Interestingly, the Io-related radio storms contain unusually rapid events that can only be properly studied using wide-band techniques.

  3. 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...

  4. Capture of Trojans by Jumping Jupiter

    CERN Document Server

    Nesvorny, David; Morbidelli, Alessandro

    2013-01-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ~5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the ...

  5. Principal components analysis of Jupiter VIMS spectra

    Science.gov (United States)

    Bellucci, G.; Formisano, V.; D'Aversa, E.; Brown, R.H.; Baines, K.H.; Bibring, J.-P.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Chamberlain, M.C.; Hansen, G.; Hibbits, K.; Showalter, M.; Filacchione, G.

    2004-01-01

    During Cassini - Jupiter flyby occurred in December 2000, Visual-Infrared mapping spectrometer (VIMS) instrument took several image cubes of Jupiter at different phase angles and distances. We have analysed the spectral images acquired by the VIMS visual channel by means of a principal component analysis technique (PCA). The original data set consists of 96 spectral images in the 0.35-1.05 ??m wavelength range. The product of the analysis are new PC bands, which contain all the spectral variance of the original data. These new components have been used to produce a map of Jupiter made of seven coherent spectral classes. The map confirms previously published work done on the Great Red Spot by using NIMS data. Some other new findings, presently under investigation, are presented. ?? 2004 Published by Elsevier Ltd on behalf of COSPAR.

  6. Jupiter's Great Red Spot and White Ovals

    Science.gov (United States)

    1979-01-01

    This photo of Jupiter was taken by Voyager 1 on the evening of March 1, 1979, from a distance of 2.7 million miles (4.3 million kilometers). The photo shows Jupiter's Great Red Spot (top) and one of the white ovals than can be seen in Jupiter's atmosphere from Earth. The white ovals were seen to form in 1939, and 1940, and have remained more or less constant ever since. None of the structure and detail evident in these features have ever been seen from Earth. The Great Red Spot is three times as large as Earth. Also evident in the picture is a great deal of atmospheric detail that will require further study for interpretation. The smallest details that can be seen in this picture are about 45 miles (80 kilometers across. JPL manages and controls the Voyager project for NASA's Office of Space Science.

  7. Capture of Irregular Satellites at Jupiter

    CERN Document Server

    Nesvorny, D; Deienno, R

    2014-01-01

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early Solar System instability when encounters between the outer planets occurred (Nesvorny, Vokrouhlicky & Morbidelli 2007, AJ 133; hereafter NVM07). NVM07 already showed that the irregular satellites of Saturn, Uranus and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary d...

  8. Numerical Modeling of the Influence of Solar Activity on the Global Circulation in the Earth’s Mesosphere and Lower Thermosphere

    Directory of Open Access Journals (Sweden)

    Igor Mingalev

    2012-01-01

    Full Text Available The nonhydrostatic model of the global neutral wind system of the earth’s atmosphere, developed earlier in the Polar Geophysical Institute, is utilized to investigate how solar activity affects the formation of the large-scale global circulation of the mesosphere and lower thermosphere. The peculiarity of the utilized model consists in that the internal energy equation for the neutral gas is not solved in the model calculations. Instead, the global temperature field is assumed to be a given distribution, that is, the input parameter of the model. Moreover, in the model calculations, not only the horizontal components but also the vertical component of the neutral wind velocity is obtained by means of a numerical solution of a generalized Navier-Stokes equation for compressible gas, so the hydrostatic equation is not applied. The simulation results indicate that solar activity ought to influence considerably on the formation of global neutral wind system in the mesosphere and lower thermosphere. The influence is conditioned by the vertical transport of air from the lower thermosphere to the mesosphere and stratosphere. This transport may be rather different under distinct solar activity conditions.

  9. The organization of Jupiter's upper tropospheric temperature structure and its evolution, 1996-1997

    Science.gov (United States)

    Fisher, Brendan M.; Orton, Glenn S.; Liu, Junjun; Schneider, Tapio; Ressler, Michael E.; Hoffman, William F.

    2016-12-01

    High signal-to-noise images of Jupiter were made at wavelengths between 13.2 and 22.8 μm in five separate observing runs between 1996 June and 1997 November at the NASA Infrared Telescope Facility. Maps of Jupiter's upper-tropospheric temperatures at pressures of 100 and 400 mbar were made from these images. We use the relatively frequent, well sampled data sets to examine in detail the short-term evolution of the temperature structure. Our 2-6 month sampling periods demonstrate that the longitudinal temperature structures evolve significantly in these short periods and exhibit wave features. Using a three-dimensional general circulation model simulation of Jupiter's upper atmosphere, we show that the thermal structures are consistent with convectively generated Rossby waves that propagate upward from the lower to the upper atmosphere.

  10. Solar Cycle/Seasonal Variations of H, D, H2 and He Distributions and Escape on Mars as Determined by the Mars Thermosphere Global Circulation Model (MTGCM)

    Science.gov (United States)

    Bougher, Stephen

    2005-01-01

    The Mars Thermosphere General Circulation Model (MTGCM) was exercised for Ls = 90 (aphelion) solar minimum, and Ls = 270 perihelion) solar maximum conditions. Simulated MTGCM outputs (i.e. helium density distributions) were compared to those previously observed for Earth and Venus. Winter polar night bulges of helium are predicted on Mars, similar to those observed on the nightside of Venus and in the winter polar regions of Earth. A poster on this research was presented at the European Geophysical Society Meeting (EGS) in 2003. This research paves the way for what might be expected in the polar night regions of Mars during upcoming aerobraking and mapping Campaigns. Lastly, Mars thermosphere (approx. 100-130 km) winter polar warming was observed at high Northern latitudes during the perihelion season, but not at high Southern latitudes during the opposite aphelion season. Presumably, the Mars thermospheric circulation is responsible for the dynamically controlled heating needed to warm polar night temperatures above radiative equilibrium values. Again, MTGCM simulations were conducted for Ls = 90 and Ls = 270 conditions; polar temperatures were examined and found to be much warmer at Northern high latitudes (perihelion) than at Southern high latitudes (aphelion), similar to Mars aerobraking datasets. The Mars thermospheric circulation is found to be stronger during perihelion solstice conditions than during aphelion conditions, owing to both stronger seasonal solar and dust heating during Mars perihelion. An invited talk was given at the Spring AGU 2004 on this research. A forthcoming GRL paper was drafted on this same topic, but not submitted before the termination of this 1-year grant.

  11. Tidal Response of Jupiter and Saturn from CMS calculationsTidal Response of Jupiter and Saturn from CMS calculations

    Science.gov (United States)

    Wahl, Sean; Hubbard, William B.; Militzer, Burkhard

    2016-10-01

    The Juno gravity science system promises to provide observational data from Jupiter's gravitational field at an unprecedented precision. Meanwhile, recent ab-initio simulations on mixtures of hydrogen and helium allow for the construction of realistic interior models. The concentric Maclaurin spheroid (CMS) numerical method has been developed for efficient, non-perturbative, self-consistent calculations of shape and gravitational field of a rotating liquid body to this desired precision. Here we present a generalization of the CMS method to three dimensions and included the effect of tides from a satellite. We have identified a number of unexpected features of the static tidal response in the case where a planet's shape is dominated by the rotational bulge. In the general case, there is state mixing of the spherical-harmonic components of the response to the corresponding components of the rotational and tidal excitations. This breaks the degeneracy of the tidal love numbers knm with m, and introduces a dependence of knm on the orbital distance of the satellite. Notably for Jupiter and Saturn, the predicted value of k2 is significantly higher when the planet's high rotation rates are taken into account: k2=0.413 for Saturn and k2=0.590 for Jupiter, accounting for an ~13% and 10% increase over the non-rotating case respectively. We have also done preliminary estimates for the off-resonance dynamic response, which may lead to an additional significant increase in k2. Accurate models of tidal response will be essential for interpreting gravity observations from Juno and future studies, particularly for when filtering for signals from interior dynamics in the observed field. This work was supported by NASA's Juno project. Sean Wahl and Burkhard Militzer acknowledge the support of the National Science Foundation (astronomy and astrophysics research grant 1412646).

  12. Limits to Determining the Core of Jupiter

    Science.gov (United States)

    Stevenson, David J.

    2016-10-01

    Simple, approximate models based on perturbations of the n=1 polytrope are used to identify some general properties of models for nearly-isentropic Jupiter-like planets where the total heavy element mass fraction is small. In these models, it is found that the radius is remarkably insensitive to the distribution of heavy elements and is effectively a measure of total heavy element enrichment (sum of core and envelope). The gravity harmonic J2 and the normalized moment of inertia α=I/MR2 are almost entirely determined by the density structure outside the core, and this depends on the reduced core mass, defined to be the actual core mass minus the mass of hydrogen and helium that would occupy that region in the absence of the core. The actual core mass or its radius or composition cannot be well determined, even when there is perfect knowledge of the equation of state, thermal state and envelope enrichment by heavy elements. The central concentration of heavy elements is approximately determined, even when the actual core is more massive and contaminated with hydrogen and helium by mixing or erosion (double diffusive convection). At fixed J2, the dependence of α on core structure is very small, and only exceeds the likely detection limit ~0.1-0.2% for very extended cores. Even though these results are obtained for a simple model, it is argued that they are semi-quantitatively applicable to realistic models. A perturbation scheme is presented for testing this systematically and for assessing the consequences of perturbations to the equation of state, compositional profile and temperature structure for the trade-off between reduced core mass and envelope enrichment.

  13. The impact of planetary-scale waves upon Venus' thermal structure in the thermosphere based upon VTGCM simulation

    Science.gov (United States)

    Brecht, Amanda; Bougher, Stephen W.; Parkinson, Chris; Shields, Drew; Liu, Hanli

    2016-10-01

    Observations of the Venusian thermal structure have been conducted by Venus Express (VEx) and its multiple instruments (i.e. SOIR, SPICAV, and VIRTIS). These VEx observations are being combined with ground based observations to create a single comprehensive database. Thus far, these observations are continuing to reveal the significant variability of Venus' upper atmosphere structure, thereby motivating an analysis of the driver(s) of this variability. A likely driver of this 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.The Venus Thermospheric General Circulation Model (VTGCM) will be utilized to examine the role planetary-scale waves play in driving Venus' thermosphere structure and variability (~80 – 200 km). Planetary-scale waves (Kelvin and Rossby waves) have been incorporated at the lower boundary of the VTGCM. The atmospheric response to these waves will be analyzed and presented. Specifically, the simulated thermal structure will be presented with and without planetary scale waves (e.g. Kelvin and Rossby waves) to (1) characterize the magnitude of change; structural change; and location of greatest impact and (2) compare with VEx and ground based observations. Since the thermal structure is strongly dependent on the global circulation, the corresponding wind and density distributions (e.g. CO2 and CO) will also be presented.

  14. Thermal tides on a hot Jupiter

    Directory of Open Access Journals (Sweden)

    Hsieh H.-F.

    2011-07-01

    Full Text Available Following the linear analysis laid out by Gu & Ogilvie 2009 (hereafter GO09, we investigate the dynamical response of a non-synchronized hot Jupiter to stellar irradiation. Besides the internal and Rossby waves considered by GO09, we study the Kelvin waves excited by the diurnal Fourier harmonic of the prograde stellar irradiation. We also present a 2-dimensional plot of internal waves excited by the semi-diurnal component of the stellar irradiation and postulate that thermal bulges may arise in a hot Jupiter. Whether our postulation is valid and is consistent with the recent results from Arras & Socrates (2009b requires further investigation.

  15. Jupiter after Pioneer - A progress report

    Science.gov (United States)

    Mcdonough, T. R.

    1974-01-01

    In December 1973, Pioneer 10 became the first spacecraft to reach the vicinity of Jupiter. The spacecraft passed through the Jovian magnetosphere in two weeks and sent back more than 300 pictures of the big planet. Measurements were conducted of EM fields, energetic particles, and micrometeoroids. Radio occultations observed are discussed along with observations in the infrared and ultraviolet range, magnetic measurements, questions of trajectory analysis, and data obtained with the aid of a plasma analyzer. Pioneer 10 has confirmed as inescapable the fact that Jupiter radiates more energy than it receives from the sun.

  16. Radiation belts of jupiter: a second look.

    Science.gov (United States)

    Fillius, R W; McIlwain, C E; Mogro-Campero, A

    1975-05-02

    The outbound leg of the Pioneer 11 Jupiter flyby explored a region farther from the equator than that traversed by Pioneer 10, and the new data require modification or augmentation of the magnetodisk model based on the Pioneer 10 flyby. The inner moons of Jupiter are sinks of energetic particles and sometimes sources. A large spike of particles was found near lo. Multiple peaks occurred in the particle fluxes near closest approach to the planet; this structure may be accounted for by a complex magnetic field configuration. The decrease in proton flux observed near minimum altitude on the Pioneer 10 flyby appears attributable to particle absorption by Amalthea.

  17. HUBBLE PROVIDES COMPLETE VIEW OF JUPITER'S AURORAS

    Science.gov (United States)

    2002-01-01

    NASA's Hubble Space Telescope has captured a complete view of Jupiter's northern and southern auroras. Images taken in ultraviolet light by the Space Telescope Imaging Spectrograph (STIS) show both auroras, the oval- shaped objects in the inset photos. While the Hubble telescope has obtained images of Jupiter's northern and southern lights since 1990, the new STIS instrument is 10 times more sensitive than earlier cameras. This allows for short exposures, reducing the blurring of the image caused by Jupiter's rotation and providing two to five times higher resolution than earlier cameras. The resolution in these images is sufficient to show the 'curtain' of auroral light extending several hundred miles above Jupiter's limb (edge). Images of Earth's auroral curtains, taken from the space shuttle, have a similar appearance. Jupiter's auroral images are superimposed on a Wide Field and Planetary Camera 2 image of the entire planet. The auroras are brilliant curtains of light in Jupiter's upper atmosphere. Jovian auroral storms, like Earth's, develop when electrically charged particles trapped in the magnetic field surrounding the planet spiral inward at high energies toward the north and south magnetic poles. When these particles hit the upper atmosphere, they excite atoms and molecules there, causing them to glow (the same process acting in street lights). The electrons that strike Earth's atmosphere come from the sun, and the auroral lights remain concentrated above the night sky in response to the 'solar wind,' as Earth rotates underneath. Earth's auroras exhibit storms that extend to lower latitudes in response to solar activity, which can be easily seen from the northern U. S. But Jupiter's auroras are caused by particles spewed out by volcanoes on Io, one of Jupiter's moons. These charged particles are then magnetically trapped and begin to rotate with Jupiter, producing ovals of auroral light centered on Jupiter's magnetic poles in both the day and night skies

  18. WARM JUPITERS NEED CLOSE ''FRIENDS'' FOR HIGH-ECCENTRICITY MIGRATION—A STRINGENT UPPER LIMIT ON THE PERTURBER'S SEPARATION

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Subo [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Road 5, Hai Dian District, Beijing 100871 (China); Katz, Boaz; Socrates, Aristotle [Institute for Advanced Study, 1 Einstein Dr., Princeton, NJ 08540 (United States)

    2014-01-20

    We propose a stringent observational test on the formation of warm Jupiters (gas-giant planets with 10 days ≲ P ≲ 100 days) by high-eccentricity (high-e) migration mechanisms. Unlike hot Jupiters, the majority of observed warm Jupiters have pericenter distances too large to allow efficient tidal dissipation to induce migration. To access the close pericenter required for migration during a Kozai-Lidov cycle, they must be accompanied by a strong enough perturber to overcome the precession caused by general relativity, placing a strong upper limit on the perturber's separation. For a warm Jupiter at a ∼ 0.2 AU, a Jupiter-mass (solar-mass) perturber is required to be ≲ 3 AU (≲ 30 AU) and can be identified observationally. Among warm Jupiters detected by radial velocities (RVs), ≳ 50% (5 out of 9) with large eccentricities (e ≳ 0.4) have known Jovian companions satisfying this necessary condition for high-e migration. In contrast, ≲ 20% (3 out of 17) of the low-e (e ≲ 0.2) warm Jupiters have detected additional Jovian companions, suggesting that high-e migration with planetary perturbers may not be the dominant formation channel. Complete, long-term RV follow-ups of the warm-Jupiter population will allow a firm upper limit to be put on the fraction of these planets formed by high-e migration. Transiting warm Jupiters showing spin-orbit misalignments will be interesting to apply our test. If the misalignments are solely due to high-e migration as commonly suggested, we expect that the majority of warm Jupiters with low-e (e ≲ 0.2) are not misaligned, in contrast with low-e hot Jupiters.

  19. Extreme Environments Technologies for Probes to Venus and Jupiter

    Science.gov (United States)

    Balint, Tibor S.; Kolawa, Elizabeth A.; Peterson, Craig E.; Cutts, James A.; Belz, Andrea P.

    2007-01-01

    This viewgraph presentation reviews the technologies that are used to mitigate extreme environments for probes at Venus and Jupiter. The contents include: 1) Extreme environments at Venus and Jupiter; 2) In-situ missions to Venus and Jupiter (past/present/future); and 3) Approaches to mitigate conditions of extreme environments for probes with systems architectures and technologies.

  20. Quasi 16-day oscillation in the mesosphere and lower thermosphere

    Science.gov (United States)

    Forbes, J. M.; Hagan, M. E.; Miyahara, S.; Vial, F.; Manson, A. H.; Meek, C. E.; Portnyagin, Y. I.

    1995-05-01

    A quasi-16-day wave in the mesosphere and lower thermosphere is investigated through analyses of radar data during January/February 1979 and through numerical simulations for various background wind conditions. Previous workers have examined about 19 days of tropospheric and stratospheric data during January 10-28, 1979, and present conflicting evidence as to whether a large westward propagating wavenumber 1 oscillation observed during this period can be identified in terms of the second symmetric Rossby normal mode of zonal wavenumber 1, commonly referred to as the ``16-day wave.'' In the present work we have applied spectral analysis techniques to meridional and zonal winds near 95 km altitude obtained from radar measurements over Obninsk, Russia (54°N, 38°E) and Saskatoon, Canada (52°N, 107°W). These data reveal oscillations of the order of +/-10 m s-1 with a period near 16 days as well as waves with periods near 5 and 10 days. These periodicities all correspond to expected resonant frequencies of atmospheric disturbances associated with westward propagating free Rossby modes of zonal wavenumber 1. Numerical simulations are performed which demonstrate that the 95-km measurements of the 16-day wave are consistent with upward extension of the oscillation determined from the tropospheric and stratospheric data. Noteworthy features of the model in terms of its applicability in the mesosphere/lower thermosphere regime are explicit inclusion of eddy and molecular diffusion of heat and momentum and realistic distributions of mean winds, especially between 80 and 100 km. The latter include a westerly wind regime above the summer easterly mesospheric jet, thus providing a ducting channel enabling interhemispheric penetration of the winter planetary wave disturbance. This serves to explain the appearance of a quasi-16-day wave recently reported in the high-latitude summer mesopause (Williams and Avery, 1992). However, the efficiency of this interhemispheric coupling

  1. On the influence of the plasma generated by comet Shoemaker-Levy 9 on Jupiter`s magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Stabile, F.; Zimbardo, G. [Arcavacata di Rende, Cosenza, Univ. della Calabria (Italy). Dipt. di Fisica

    1997-11-01

    The impact of comet Shoemaker-Levy 9 with Jupiter has created a variety of magnetospheric plasmas which were detected by their electromagnetic emissions. By means of the Dessler-Parker-Sckopke relation we estimate the perturbation of Jupiter`s magnetic field. It appears that the produced plasma may explain the observed decrease of UV lines in Io`s torus.

  2. Empirical model of atomic nitrogen in the upper thermosphere

    Science.gov (United States)

    Engebretson, M. J.; Mauersberger, K.; Kayser, D. C.; Potter, W. E.; Nier, A. O.

    1977-01-01

    Atomic nitrogen number densities in the upper thermosphere measured by the open source neutral mass spectrometer (OSS) on Atmosphere Explorer-C during 1974 and part of 1975 have been used to construct a global empirical model at an altitude of 375 km based on a spherical harmonic expansion. The most evident features of the model are large diurnal and seasonal variations of atomic nitrogen and only a moderate and latitude-dependent density increase during periods of geomagnetic activity. Maximum and minimum N number densities at 375 km for periods of low solar activity are 3.6 x 10 to the 6th/cu cm at 1500 LST (local solar time) and low latitude in the summer hemisphere and 1.5 x 10 to the 5th/cu cm at 0200 LST at mid-latitudes in the winter hemisphere.

  3. Thermospheric density model biases at the 23rd sunspot maximum

    Science.gov (United States)

    Pardini, C.; Moe, K.; Anselmo, L.

    2012-07-01

    Uncertainties in the neutral density estimation are the major source of aerodynamic drag errors and one of the main limiting factors in the accuracy of the orbit prediction and determination process at low altitudes. Massive efforts have been made over the years to constantly improve the existing operational density models, or to create even more precise and sophisticated tools. Special attention has also been paid to research more appropriate solar and geomagnetic indices. However, the operational models still suffer from weakness. Even if a number of studies have been carried out in the last few years to define the performance improvements, further critical assessments are necessary to evaluate and compare the models at different altitudes and solar activity conditions. Taking advantage of the results of a previous study, an investigation of thermospheric density model biases during the last sunspot maximum (October 1999 - December 2002) was carried out by analyzing the semi-major axis decay of four satellites: Cosmos 2265, Cosmos 2332, SNOE and Clementine. Six thermospheric density models, widely used in spacecraft operations, were analyzed: JR-71, MSISE-90, NRLMSISE-00, GOST-2004, JB2006 and JB2008. During the time span considered, for each satellite and atmospheric density model, a fitted drag coefficient was solved for and then compared with the calculated physical drag coefficient. It was therefore possible to derive the average density biases of the thermospheric models during the maximum of the 23rd solar cycle. Below 500 km, all the models overestimated the average atmospheric density by amounts varying between +7% and +20%. This was an inevitable consequence of constructing thermospheric models from density data obtained by assuming a fixed drag coefficient, independent of altitude. Because the uncertainty affecting the drag coefficient measurements was about 3% at both 200 km and 480 km of altitude, the calculated air density biases below 500 km were

  4. Water and Water Ions in the Martian Thermosphere/Ionosphere

    Science.gov (United States)

    Fox, J. L.; Benna, M.; Mahaffy, P. R.; Jakosky, B. M.

    2015-12-01

    We present here the first model of the Martian thermosphere/ionosphere in which we predict the density profiles of water vapor and water ions in the altitude range 80 to 400 km. The model is based on data from the MAVEN spacecraft, including the NGIMS, LPW, EUVM and STATIC. The model includes 28 ions, of which 14 are protonated species, and 10 minor neutral species. The protonated species include H2O+ and H3O+, and the minor neutral species include H2O. These species are coupled to each other and to the background species by over 400 reactions. The peaks of the density profiles of water ions and OH+ are in fairly good agreement with the values measured by the NGIMS instrument. The density profiles of water vapor are computed with zero flux boundary conditions at the top and bottom of the model, which shows that water can be made in situ via ion chemistry, somewhat like in the interstelllar medium. It appears, however, that the predicted densities may be too small to account for the densities of H3O+ that are seen at low altitudes beyond the terminator. On the other hand, the densities of water vapor must be small enough so that HCO+ is not destroyed completely by proton transfer. The actual amount of water in the thermosphere is bracketed by these two requirements. The computed water vapor densities at the lower boundary are smaller than some of those at the upper boundaries of middle atmosphere models. We tentatively predict that there must be some influx of water from below. We also compute the Hn + species, where n=(1-3), and convincingly demonstrate the the mass-2 ion is H2+ and not D+, as it is on Venus.

  5. Numerical simulations of thermospheric dynamics: divergence as a proxy for vertical winds

    Directory of Open Access Journals (Sweden)

    S. L. Cooper

    2009-06-01

    Full Text Available A local scale, time dependent three-dimensional model of the neutral thermosphere was used to test the applicability of two previously published empirical relations between thermospheric vertical wind and velocity divergence, i.e., those due to Burnside et al. (1981 and Brekke (1997. The model self-consistently solves for vertical winds driven by heat and momentum deposited into the neutral atmosphere by high latitude ion convection. The Brekke condition accurately mimicked the overall "shape" of the three-dimensional model vertical wind field although, as written, it consistently overestimated the vertical wind magnitude by a factor of approximately 5/3, for the heating scenarios that we considered. This same general behavior was observed regardless of whether the forcing was static or rapidly changing with time. We discuss the likely reason for the Brekke condition overestimating the magnitude of our vertical winds, and suggest an alternative condition that should better describe vertical winds that are driven by local heating. The applicability of the Burnside condition was, by contrast, quite variable. During static heating, both the magnitude and the sign of the model vertical winds were predicted reliably at heights above those of maximum energy and momentum deposition per unit mass. However, below the thermal forcing, the Burnside condition predicted vertical winds of the wrong sign. It also introduced significant artefacts into the predicted vertical wind field when the forcing changed suddenly with time. If these results are of general applicability (which seems likely, given the way these relations are derived then the Burnside condition could usually be used safely at altitudes above hmF2. But it should be avoided below this height at all times, and even at high altitudes during periods of dynamic forcing. While the Brekke condition (or our modified version of it could likely be used in all circumstances

  6. Influence of solar variability on the infrared radiative cooling of the thermosphere from 2002 to 2014.

    Science.gov (United States)

    Mlynczak, Martin G; Hunt, Linda A; Mertens, Christopher J; Thomas Marshall, B; Russell, James M; Woods, Thomas; Earl Thompson, R; Gordley, Larry L

    2014-04-16

    Infrared radiative cooling of the thermosphere by carbon dioxide (CO2, 15 µm) and by nitric oxide (NO, 5.3 µm) has been observed for 12 years by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite. For the first time we present a record of the two most important thermospheric infrared cooling agents over a complete solar cycle. SABER has documented dramatic variability in the radiative cooling on time scales ranging from days to the 11 year solar cycle. Deep minima in global mean vertical profiles of radiative cooling are observed in 2008-2009. Current solar maximum conditions, evidenced in the rates of radiative cooling, are substantially weaker than prior maximum conditions in 2002-2003. The observed changes in thermospheric cooling correlate well with changes in solar ultraviolet irradiance and geomagnetic activity during the prior maximum conditions. NO and CO2 combine to emit 7 × 10(18) more Joules annually at solar maximum than at solar minimum. First record of thermospheric IR cooling rates over a complete solar cycleIR cooling in current solar maximum conditions much weaker than prior maximumVariability in thermospheric IR cooling observed on scale of days to 11 years.

  7. JUPITER PROJECT - MERGING INVERSE PROBLEM FORMULATION TECHNOLOGIES

    Science.gov (United States)

    The JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) project seeks to enhance and build on the technology and momentum behind two of the most popular sensitivity analysis, data assessment, calibration, and uncertainty analysis programs used in envi...

  8. Dramatic Change in Jupiter's Great Red Spot

    Science.gov (United States)

    Simon, A. A.; Wong, M. H.; Rogers, J. H.; Orton, G. S.; de Pater, I.; Asay-Davis, X.; Carlson, R. W.; Marcus, P. S.

    2015-01-01

    Jupiter's Great Red Spot (GRS) is one of its most distinct and enduring features, having been continuously observed since the 1800's. It currently spans the smallest latitude and longitude size ever recorded. Here we show analyses of 2014 Hubble spectral imaging data to study the color, structure and internal dynamics of this long-live storm.

  9. Towards Chemical Constraints on Hot Jupiter Migration

    CERN Document Server

    Madhusudhan, Nikku; Kennedy, Grant M

    2014-01-01

    The origin of hot Jupiters -- gas giant exoplanets orbiting very close to their host stars -- is a long-standing puzzle. Planet formation theories suggest that such planets are unlikely to have formed in-situ but instead may have formed at large orbital separations beyond the snow line and migrated inward to their present orbits. Two competing hypotheses suggest that the planets migrated either through interaction with the protoplanetary disk during their formation, or by disk-free mechanisms such as gravitational interactions with a third body. Observations of eccentricities and spin-orbit misalignments of hot Jupiter systems have been unable to differentiate between the two hypotheses. In the present work, we suggest that chemical depletions in hot Jupiter atmospheres might be able to constrain their migration mechanisms. We find that sub-solar carbon and oxygen abundances in Jovian-mass hot Jupiters around Sun-like stars are hard to explain by disk migration. Instead, such abundances are more readily expla...

  10. Jupiter as a Giant Cosmic Ray Detector

    CERN Document Server

    Rimmer, Paul B; Helling, Christiane

    2014-01-01

    We explore the feasibility of using the atmosphere of Jupiter to detect Ultra-High-Energy Cosmic Rays (UHECR's). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of $3.3 \\times 10^7$ km$^2$. We predict that Fermi-LAT should be able to detect events of energy $>10^{21}$ eV with fluence $10^{-7}$ erg cm$^{-2}$ at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays $\\gtrsim 10^{20}$ eV. Extensive air showers also produce a synchrotron signature that may ...

  11. The Origin of Retrograde Hot Jupiters

    Science.gov (United States)

    Naoz, Smadar; Farr, W.; Lithwick, Y.; Rasio, F.; Teyssandier, J.

    2011-09-01

    The search for extra-solar planets has led to the surprising discovery of many Jupiter-like planets in very close proximity to their host star, the so-called ``hot Jupiters'' (HJ). Even more surprisingly, many of these HJs have orbits that are eccentric or highly inclined with respect to the equator of the star, and some (about 25%) even orbiting counter to the spin direction of the star. This poses a unique challenge to all planet formation models. We show that secular interactions between Jupiter-like planet and another perturber in the system can easily produce retrograde HJ orbits. We show that in the frame of work of secular hierarchical triple system (the so-called Kozai mechanism) the inner orbit's angular momentum component parallel to the total angular momentum (i.e., the z-component of the inner orbit angular momentum) need not be constant. In fact, it can even change sign, leading to a retrograde orbit. A brief excursion to very high eccentricity during the chaotic evolution of the inner orbit allows planet-star tidal interactions to rapidly circularize that orbit, decoupling the planets and forming a retrograde hot Jupiter. We estimate the relative frequencies of retrograde orbits and counter to the stellar spin orbits using Monte Carlo simulations, and find that the they are consistent with the observations. The high observed incidence of planets orbiting counter to the stellar spin direction may suggest that planet--planet secular interactions are an important part of their dynamical history.

  12. Hot Jupiters and Super-Earths

    CERN Document Server

    Mustill, Alexander James; Johansen, Anders

    2016-01-01

    We explore the role of dynamics in shaping planetary system multiplicities, focussing on two particular problems. (1) We propose that the lack of close-in super-Earths in hot Jupiter systems is a signature of the migration history of the hot Jupiters and helps to discriminate between different mechanisms of migration. We present N-body simulations of dynamical migration scenarios where proto-hot Jupiters are excited to high eccentricities prior to tidal circularisation and orbital decay. We show that in this scenario, the eccentric giant planet typically destroys planets in the inner system, in agreement with the observed lack of close super-Earth companions to hot Jupiters. (2) We explore the role of the dynamics of outer systems in affecting the multiplicities of close-in systems such as those discovered by Kepler. We consider specifically the effects of planet--planet scattering and Kozai perturbations on an exterior giant planet on the architecture of the inner system, and evaluate the ability of such sce...

  13. Europa--Jupiter's Icy Ocean Moon

    Science.gov (United States)

    Lowes, L.

    1999-01-01

    Europa is a puzzle. The sixth largest moon in our solar system, Europa confounds and intrigues scientists. Few bodies in the solar system have attracted as much scientific attention as this moon of Jupiter because of its possible subsurface ocean of water. The more we learn about this icy moon, the more questions we have.

  14. JunoCam's Imaging of Jupiter

    Science.gov (United States)

    Orton, Glenn; Hansen, Candice; Momary, Thomas; Caplinger, Michael; Ravine, Michael; Atreya, Sushil; Ingersoll, Andrew; Bolton, Scott; Rogers, John; Eichstaedt, Gerald

    2017-04-01

    Juno's visible imager, JunoCam, is a wide-angle camera (58° field of view) with 4 color filters: red, green and blue (RGB) and methane at 889 nm, designed for optimal imaging of Jupiter's poles. Juno's elliptical polar orbit offers unique views of Jupiter's polar regions with spatial scales as good as 50 km/pixel. At closest approach ("perijove") the images have spatial scale down to ˜3 km/pixel. As a push-frame imager on a rotating spacecraft, JunoCam uses time-delayed integration to take advantage of the spacecraft spin to extend integration time to increase signal. Images of Jupiter's poles reveal a largely uncharted region of Jupiter, as nearly all earlier spacecraft except Pioneer 11 have orbited or flown by close to the equatorial plane. Poleward of 64-68° planetocentric latitude, Jupiter's familiar east-west banded structure breaks down. Several types of discrete features appear on a darker, bluish-cast background. Clusters of circular cyclonic spirals are found immediately around the north and south poles. Oval-shaped features are also present, ranging in size down to JunoCam's resolution limits. The largest and brightest features usually have chaotic shapes; animations over ˜1 hour can reveal cyclonic motion in them. Narrow linear features traverse tens of degrees of longitude and are not confined in latitude. JunoCam also detected optically thin clouds or hazes that are illuminated beyond the nightside ˜1-bar terminator; one of these detected at Perijove lay some 3 scale heights above the main cloud deck. Tests have been made to detect the aurora and lightning. Most close-up images of Jupiter have been acquired at lower latitudes within 2 hours of closest approach. These images aid in understanding the data collected by other instruments on Juno that probe deeper in the atmosphere. When Jupiter was too close to the sun for ground-based observers to collect data between perijoves 1 and 2, JunoCam took a sequence of routine images to monitor large

  15. Jupiter internal structure: the effect of different equations of state

    CERN Document Server

    Miguel, Yamila; Fayon, Lucile

    2016-01-01

    Heavy elements, even though its smaller constituent, are crucial to understand Jupiter formation history. Interior models are used to determine the amount of heavy elements in Jupiter interior, nevertheless this range is still subject to degeneracies due to uncertainties in the equations of state. Prior to Juno mission data arrival, we present Jupiter optimized calculations exploring the effect of different model parameters in the determination of Jupiter's core and heavy element's mass. We perform comparisons between equations of state published recently. The interior model of Jupiter is calculated from the equations of hydrostatic equilibrium, mass and energy conservation, and energy transport. The mass of the core and heavy elements is adjusted to match Jupiter's observational constrains radius and gravitational moments. We show that the determination of Jupiter interior structure is tied to the estimation of its gravitational moments and the accuracy of equations of state of hydrogen, helium and heavy ele...

  16. The EJSM Jupiter-Europa Orbiter: Mission Overview

    Science.gov (United States)

    Pappalardo, R. T.; Clark, K.; Greeley, R.; Hendrix, A. R.; Tan-Wang, G.; Lock, R.; van Houten, T.; Ludwinski, J.; Petropoulis, A.; Jun, I.; Boldt, J.; Kinnison, J.

    2008-09-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address key components of the complete EJSM science objectives and would be designed to function alone or in conjunction with the ESA-led Jupiter Ganymede Orbiter and JAXA-led Jupiter Magnetospheric Orbiter. The JEO mission concept uses a single orbiter flight system which would travel to Jupiter to perform a multi-year study of the Jupiter system and Europa, including 2.5-3 years of Jupiter system science and a comprehensive Europa orbit phase of upt ot a year. This abstract describes the design concept of this mission.

  17. Thermospheric circulation model in meridian plane (I)——Storm time variations in thermal status and circulation

    Institute of Scientific and Technical Information of China (English)

    萧佐; 王劲松

    2000-01-01

    A thermospheric circulation model in meridian plane (TCMMP) is introduced and a case study on the variations in night side thermosphere caused by energy deposition in auroral oval during a single magnetic substorm is expounded. Calculations show that TCMMP can correctly reflect the thermospheric thermal status and circulation patterns during storm time and the results are in agreement with previous theoretical and observational ones. This paper and other works also show the validity of TCMMP in researches on medium and large scale changes in mid- and low latitude thermosphere. Results also support strongly some related theory about the cause of ionospheric storms, expecially the negative phase storms.

  18. ON THE FORMATION OF HOT JUPITERS IN STELLAR BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Naoz, Smadar [Harvard Smithsonian Center for Astrophysics, Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States); Farr, Will M.; Rasio, Frederic A. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, Evanston, IL 60208 (United States)

    2012-08-01

    We study the production of hot Jupiters (HJs) in stellar binaries. We show that the 'eccentric Kozai-Lidov' (EKL) mechanism can play a key role in the dynamical evolution of a star-planet-star triple system. We run a large set of Monte Carlo simulations including the secular evolution of the orbits, general relativistic precession, and tides, and we determine the semimajor axis, eccentricity, inclination, and spin-orbit angle distributions of the HJs that are produced. We explore the effect of different tidal friction parameters on the results. We find that the efficiency of forming HJs when taking the EKL mechanism into account is higher then previously estimated. Accounting for the frequency of stellar binaries, we find that this production mechanism can account for about 30% of the observed HJ population. Current observations of spin-orbit angles are consistent with this mechanism producing {approx}30% of all HJs, and up to 100% of the misaligned systems. Based on the properties of binaries without an HJ in our simulations, we predict the existence of many Jupiter-like planets with moderately eccentric and inclined orbits and semimajor axes of several AU.

  19. On the Formation of Hot Jupiters in Stellar Binaries

    Science.gov (United States)

    Naoz, Smadar; Farr, Will M.; Rasio, Frederic A.

    2012-08-01

    We study the production of hot Jupiters (HJs) in stellar binaries. We show that the "eccentric Kozai-Lidov" (EKL) mechanism can play a key role in the dynamical evolution of a star-planet-star triple system. We run a large set of Monte Carlo simulations including the secular evolution of the orbits, general relativistic precession, and tides, and we determine the semimajor axis, eccentricity, inclination, and spin-orbit angle distributions of the HJs that are produced. We explore the effect of different tidal friction parameters on the results. We find that the efficiency of forming HJs when taking the EKL mechanism into account is higher then previously estimated. Accounting for the frequency of stellar binaries, we find that this production mechanism can account for about 30% of the observed HJ population. Current observations of spin-orbit angles are consistent with this mechanism producing ~30% of all HJs, and up to 100% of the misaligned systems. Based on the properties of binaries without an HJ in our simulations, we predict the existence of many Jupiter-like planets with moderately eccentric and inclined orbits and semimajor axes of several AU.

  20. Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

    Directory of Open Access Journals (Sweden)

    Connor Hyunju Kim

    2016-01-01

    Full Text Available The magnetosphere is a major source of energy for the Earth’s ionosphere and thermosphere (IT system. Current IT models drive the upper atmosphere using empirically calculated magnetospheric energy input. Thus, they do not sufficiently capture the storm-time dynamics, particularly at high latitudes. To improve the prediction capability of IT models, a physics-based magnetospheric input is necessary. Here, we use the Open Global General Circulation Model (OpenGGCM coupled with the Coupled Thermosphere Ionosphere Model (CTIM. OpenGGCM calculates a three-dimensional global magnetosphere and a two-dimensional high-latitude ionosphere by solving resistive magnetohydrodynamic (MHD equations with solar wind input. CTIM calculates a global thermosphere and a high-latitude ionosphere in three dimensions using realistic magnetospheric inputs from the OpenGGCM. We investigate whether the coupled model improves the storm-time IT responses by simulating a geomagnetic storm that is preceded by a strong solar wind pressure front on August 24, 2005. We compare the OpenGGCM-CTIM results with low-earth-orbit satellite observations and with the model results of Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe. CTIPe is an up-to-date version of CTIM that incorporates more IT dynamics such as a low-latitude ionosphere and a plasmasphere, but uses empirical magnetospheric input. OpenGGCM-CTIM reproduces localized neutral density peaks at ~ 400 km altitude in the high-latitude dayside regions in agreement with in situ observations during the pressure shock and the early phase of the storm. Although CTIPe is in some sense a much superior model than CTIM, it misses these localized enhancements. Unlike the CTIPe empirical input models, OpenGGCM-CTIM more faithfully produces localized increases of both auroral precipitation and ionospheric electric fields near the high-latitude dayside region after the pressure shock and after the storm onset

  1. Statistical analysis of thermospheric gravity waves from Fabry-Perot Interferometer measurements of atomic oxygen

    Directory of Open Access Journals (Sweden)

    E. A. K. Ford

    2008-02-01

    Full Text Available Data from the Fabry-Perot Interferometers at KEOPS (Sweden, Sodankylä (Finland, and Svalbard (Norway, have been analysed for gravity wave activity on all the clear nights from 2000 to 2006. A total of 249 nights were available from KEOPS, 133 from Sodankylä and 185 from the Svalbard FPI. A Lomb-Scargle analysis was performed on each of these nights to identify the periods of any wave activity during the night. Comparisons between many nights of data allow the general characteristics of the waves that are present in the high latitude upper thermosphere to be determined. Comparisons were made between the different parameters: the atomic oxygen intensities, the thermospheric winds and temperatures, and for each parameter the distribution of frequencies of the waves was determined. No dependence on the number of waves on geomagnetic activity levels, or position in the solar cycle, was found. All the FPIs have had different detectors at various times, producing different time resolutions of the data, so comparisons between the different years, and between data from different sites, showed how the time resolution determines which waves are observed. In addition to the cutoff due to the Nyquist frequency, poor resolution observations significantly reduce the number of short-period waves (<1 h period that may be detected with confidence. The length of the dataset, which is usually determined by the length of the night, was the main factor influencing the number of long period waves (>5 h detected. Comparisons between the number of gravity waves detected at KEOPS and Sodankylä over all the seasons showed a similar proportion of waves to the number of nights used for both sites, as expected since the two sites are at similar latitudes and therefore locations with respect to the auroral oval, confirming this as a likely source region. Svalbard showed fewer waves with short periods than KEOPS data for a season when both had the same time resolution data

  2. New results on equatorial thermospheric winds and the midnight temperature maximum

    Energy Technology Data Exchange (ETDEWEB)

    Meriwether, J.; Faivre, M.; Fesen, C. [Clemson Univ., SC (United States). Dept. of Physics and Astronomy; Sherwood, P. [Interactive Technology, Waban, MA (United States); Veliz, O. [Inst. Geofisica del Peru, Lima (Peru). Radio Observatorio de Jicamarca

    2008-07-01

    Optical observations of thermospheric winds and temperatures determined with high resolution measurements of Doppler shifts and Doppler widths of the OI 630-nm equatorial nightglow emission have been made with improved accuracy at Arequipa, Peru (16.4 S, 71.4 W) with an imaging Fabry-Perot interferometer. An observing procedure previously used at Arecibo Observatory was applied to achieve increased spatial and temporal sampling of the thermospheric wind and temperature with the selection of eight azimuthal directions, equally spaced from 0 to 360 , at a zenith angle of 60 . By assuming the equivalence of longitude and local time, the data obtained using this technique is analyzed to determine the mean neutral wind speeds and mean horizontal gradients of the wind field in the zonal and meridional directions. The new temperature measurements obtained with the improved instrumental accuracy clearly show the midnight temperature maximum (MTM) peak with amplitudes of 25 to 200 K in all directions observed for most nights. The horizontal wind field maps calculated from the mean winds and gradients show the MTM peak is always preceded by an equatorward wind surge lasting 1-2 h. The results also show for winter events a meridional wind abatement seen after the MTM peak. On one occasion, near the September equinox, a reversal was observed during the poleward transit of the MTM over Arequipa. Analysis inferring vertical winds from the observed convergence yielded inconsistent results, calling into question the validity of this calculation for the MTM structure at equatorial latitudes during solar minimum. Comparison of the observations with the predictions of the NCAR general circulation model indicates that the model fails to reproduce the observed amplitude by a factor of 5 or more. This is attributed in part to the lack of adequate spatial resolution in the model as the MTM phenomenon takes place within a scale of 300-500 km and {proportional_to}45 min in local time. The

  3. Three spacecraft observe Jupiter's glowing polar regions

    Science.gov (United States)

    1996-09-01

    The aurorae on Jupiter are like the Aurorae Borealis and Australis on the Earth, although visible only by ultraviolet light. They flicker in a similar way in response to variations in the solar wind of charged particles blowing from the Sun. While Galileo monitored the changing environment of particles and magnetism in Jupiter's vicinity, IUE recorded surprisingly large and rapid variations in the overall strength of the auroral activity. IUE's main 45-centimetre telescope did not supply images,but broke up the ultraviolet rays into spectra, like invisible rainbows, from which astrophysicists could deduce chemical compositions, motions and temperatures in the cosmic objects under examination. In the case of Jupiter's aurorae, the strongest emission came from activated hydrogen atoms at a wavelength of 1216 angstroms. The Hubble Space Telescope's contributions to the International Jupiter Watch included images showing variations in the form of the aurorae, and "close-up" spectra of parts of the auroral ovals. Astronomers will compare the flickering aurorae on Jupiter with concurrent monitoring of the Sun and the solar wind by the ESA-NASA SOHO spacecraft and several satellites of the Interagency Solar-Terrestrial Programme. It is notable that changes in auroral intensity by a factor of two or three occurred during the 1996 observational period, even though the Sun was in an exceptionally quiet phase, with very few sunspots. In principle, a watch on Jupiter's aurorae could become a valuable means of checking the long-range effects of solar activity, which also has important consequences for the Earth. The situation at Jupiter is quite different from the Earth's, with the moons strongly influencing the planet's space environment. But with Hubble busy with other work, any such Jupiter-monitoring programme will have to await a new ultraviolet space observatory. IUE observed Jupiter intensively in 1979-80 in conjunction with the visits of NASA's Voyager spacecraft, and

  4. Validation of the MIPAS CO2 volume mixing ratio in the mesosphere and lower thermosphere and comparison with WACCM simulations

    Science.gov (United States)

    López-Puertas, Manuel; Funke, B.; Jurado-Navarro, Á. A.; García-Comas, M.; Gardini, A.; Boone, C. D.; Rezac, L.; Garcia, R. R.

    2017-08-01

    We present the validation of Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) CO2 daytime concentration in the mesosphere and lower thermosphere by comparing with Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) data. MIPAS shows a very good agreement with ACE below 100 km with differences of ˜5%. Above 100 km, MIPAS CO2 is generally lower than ACE with differences growing from ˜5% at 100 km to 20-40% near 110-120 km. Part of this disagreement can be explained by the lack of a nonlocal thermodynamic equilibrium correction in ACE. MIPAS also agrees very well (˜5%) with SABER below 100 km. At 90-105 km, MIPAS is generally smaller than SABER by 10-30% in the polar summers. At 100-120 km, MIPAS and SABER CO2 agree within ˜10% during equinox but, for solstice, MIPAS is larger by 10-25%, except near the polar summer. Whole Atmosphere Community Climate Model (WACCM) CO2 shows the major MIPAS features. At 75-100 km, the agreement is very good (˜5%), with maximum differences of ˜10%. At 95-115 km MIPAS CO2 is larger than WACCM by 20-30% in the winter hemisphere but smaller (20-40%) in the summer. Above 95-100 km WACCM generally overestimates MIPAS CO2 by about 20-80% except in the polar summer where underestimates it by 20-40%. MIPAS CO2 favors a large eddy diffusion below 100 km and suggests that the meridional circulation of the lower thermosphere is stronger than in WACCM. The three instruments and WACCM show a clear increase of CO2 with time, more markedly at 90-100 km.

  5. Warm Jupiters from Secular Planet–Planet Interactions

    Science.gov (United States)

    Petrovich, Cristobal; Tremaine, Scott

    2016-10-01

    Most warm Jupiters (gas-giant planets with 0.1 {{au}}≲ a≲ 1 au) have pericenter distances that are too large for significant orbital migration by tidal friction. We study the possibility that the warm Jupiters are undergoing secular eccentricity oscillations excited by an outer companion (a planet or star) in an eccentric and/or mutually inclined orbit. In this model, the warm Jupiters migrate periodically, in the high-eccentricity phase of the oscillation, but are typically observed at lower eccentricities. We show that in this model the steady-state eccentricity distribution of the warm Jupiters is approximately flat, which is consistent with the observed distribution if we restrict the sample to warm Jupiters with detected outer planetary companions. The eccentricity distribution of warm Jupiters without companions exhibits a peak at e≲ 0.2 that must be explained by a different formation mechanism. Based on a population synthesis study, we find that high-eccentricity migration excited by an outer planetary companion (1) can account for ∼ 20 % of the warm Jupiters and most of the warm Jupiters with e≳ 0.4; and (2) can produce most of the observed population of hot Jupiters, with a semimajor axis distribution that matches the observations, but fails to account adequately for ∼ 60 % of hot Jupiters with projected obliquities ≲ 20^\\circ . Thus ∼ 20 % of the warm Jupiters and ∼ 60 % of the hot Jupiters can be produced by high-eccentricity migration. We also provide predictions for the expected mutual inclinations and spin-orbit angles of the planetary systems with hot and warm Jupiters produced by high-eccentricity migration.

  6. Lagrangian Coherent Structures in a Non-Euclidean Global Thermosphere

    Science.gov (United States)

    Wang, N.; Ramirez, U.; Flores, F.; Datta-Barua, S.

    2016-12-01

    Lagrangian Coherent Structures (LCSs) are manifolds of maximum divergence or convergence in 2D or 3D time-varying flow fields. The study of LCSs has been used to predict material transport in numerous geophysical flows. The most commonly used computational method for finding LCSs is to compute the finite time Lyapunov exponent (FTLE), a scalar field measuring the ratio of stretching after a given interval of time among neighboring particles, relative to their initial separation. LCS ridges are located at the local maxima of the FTLE. The LCS must be objective (frame-invariant for different observers), and the technique for computing the FTLE that determines the LCS typically assumes a Euclidean domain. Previous work showed that LCSs are likely to exist globally at high latitudes using the Euclidean norm. Here we refine that calculation by deriving the FTLE calculation for the Riemannian manifold of a spherical surface, and applying it to the thermospheric layer of the atmosphere globally. The thermosphere is treated as a closed spherical 2D domain on which the fluid flows, assuming negligible vertical flow. The domain is discretized in longitude and latitude, and the Horizontal Wind Model 2014 (HWM14) is used to generate the 2D velocity field at each grid point, each of which is a ground speed in the local east-north-up (ENU) frame. To make the LCS objective, the ground speed in each local ENU frame is converted to angular velocity in the earth-centered earth-fixed (ECEF) coordinates. Using bilinear interpolation and including the rotational velocity of Earth to transform to an inertial frame, we trace the trajectory of each particle to compute the final positions after the integration time. Replacing the Euclidean distance between particles with the great circle distance gives the FTLE scalar field from which the LCSs can be identified. We find and illustrate objective LCSs in the neutral wind flow field at high latitudes by applying this algorithm for the

  7. 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.

  8. Jumping Jupiter can explain Mercury's orbit

    CERN Document Server

    Roig, Fernando; DeSouza, Sandro Ricardo

    2016-01-01

    The orbit of Mercury has large values of eccentricity and inclination that cannot be easily explained if this planet formed on a circular and coplanar orbit. Here, we study the evolution of Mercury's orbit during the instability related to the migration of the giant planets in the framework of the jumping Jupiter model. We found that some instability models are able to produce the correct values of Mercury's eccentricity and inclination, provided that relativistic effects are included in the precession of Mercury's perihelion. The orbital excitation is driven by the fast change of the normal oscillation modes of the system corresponding to the perihelion precession of Jupiter (for the eccentricity), and the nodal regression of Uranus (for the inclination).

  9. The EJSM Jupiter Europa Orbiter: Planning Payload

    Science.gov (United States)

    Pappalardo, R. T.; Clark, K.; Greeley, R.; Hendrix, A. R.; Boldt, J.; Tan-Wang, G.; Lock, R.; van Houten, T.; Ludwinski, J.

    2008-09-01

    In the decade since the first return of Europa data by the Galileo spacecraft, the scientific understanding of Europa has greatly matured leading to the formulation of sophisticated new science objectives to be addressed through the acquisition of new data. The Jupiter Europa Orbiter (JEO) is one component of the proposed multi-spacecraft Europa Jupiter System Mission (EJSM) designed to obtain data in support of these new science objectives. The JEO planning payload, while notional, is used to quantify engineering aspects of the mission and spacecraft design, and operational scenarios required to obtain the data necessary to meet the science objectives. The instruments were defined to understand the viability of an approach to meet the measurement objectives, perform in the radiation environment and meet the planetary protection requirements. The actual instrument suite would ultimately be the result of an Announcement of Opportunity (AO) selection process carried out by NASA.

  10. Radiation Environment for the Jupiter Europa Orbiter

    Science.gov (United States)

    Jun, Insoo

    2008-09-01

    One of the major challenges for the Jupiter Europa Orbiter (JEO) mission would be that the spacecraft should be designed to survive an intense radiation environment expected at Jupiter and Europa. The proper definition of the radiation environments is the important first step, because it could affect almost every aspects of mission and spacecraft design. These include optimizing the trajectory to minimize radiation exposure, determining mission lifetime, selecting parts, materials, detectors and sensors, shielding design, etc. The radiation environments generated for the 2008 JEO study will be covered, emphasizing the radiation environment mainly responsible for the total ionizing dose (TID) and displacement damage dose (DDD). The latest models developed at JPL will be used to generate the TID and DDD environments. Finally, the major radiation issues will be summarized, and a mitigation plan will be discussed.

  11. The Escaping Upper Atmospheres of Hot Jupiters

    Science.gov (United States)

    Davidson, Eric; Jones, Gabrielle; Uribe, Ana; Carson, Joseph

    2017-01-01

    Hot Jupiters are massive gaseous planets which orbit closely to their parent star. The strong stellar irradiation at these small orbital separations causes the temperature of the upper atmosphere of the planet to rise. This can cause the planet's atmosphere to escape into space, creating an exoplanet outflow. We ascertained which factors determine the presence and structure of these outflows by creating one dimensional simulations of the density, pressure, velocity, optical depth, and neutral fraction of hot Jupiter atmospheres. This was done for planets of masses and radii ranging from 0.5-1.5 Mj and 0.5-1.5 Rj. We found the outflow rate to be highest for a planet of 0.5 Mj and 1.5 Rj at 5.3×10-14 Mj/Yr. We also found that the higher the escape velocity, the lower the chance of the planet having an outflow.

  12. Secular orbital evolution of Jupiter family comets

    Science.gov (United States)

    Rickman, H.; Gabryszewski, R.; Wajer, P.; Wiśniowski, T.; Wójcikowski, K.; Szutowicz, S.; Valsecchi, G. B.; Morbidelli, A.

    2017-02-01

    Context. The issue of the long term dynamics of Jupiter family comets (JFCs) involves uncertain assumptions about the physical evolution and lifetimes of these comets. Contrary to what is often assumed, real effects of secular dynamics cannot be excluded and therefore merit investigation. Aims: We use a random sample of late heavy bombardment cometary projectiles to study the long-term dynamics of JFCs by a Monte Carlo approach. In a steady-state picture of the Jupiter family, we investigate the orbital distribution of JFCs, including rarely visited domains like retrograde orbits or orbits within the outer parts of the asteroid main belt. Methods: We integrate 100 000 objects over a maximum of 100 000 orbital revolutions including the Sun, a comet, and four giant planets. Considering the steady-state number of JFCs to be proportional to the total time spent in the respective orbital domain, we derive the capture rate based on observed JFCs with small perihelia and large nuclei. We consider a purely dynamical model and one where the nuclei are eroded by ice sublimation. Results: The JFC inclination distribution is incompatible with our erosional model. This may imply that a new type of comet evolution model is necessary. Considering that comets may live for a long time, we show that JFCs can evolve into retrograde orbits as well as asteroidal orbits in the outer main belt or Cybele regions. The steady-state capture rate into the Jupiter family is consistent with 1 × 109 scattered disk objects with diameters D > 2 km. Conclusions: Our excited scattered disk makes it difficult to explain the JFC inclination distribution, unless the physical evolution of JFCs is more intricate than assumed in standard, erosional models. Independent of this, the population size of the Jupiter family is consistent with a relatively low-mass scattered disk.

  13. Modelling of Jupiter's Innermost Radiation Belt

    Science.gov (United States)

    Mihalov, J. D.; DeVincenzi, Donald (Technical Monitor)

    1999-01-01

    In order to understand better source and loss processes for energetic trapped protons near Jupiter, a modification of de Pater and Goertz' finite difference diffusion calculations for Jovian equatorial energetic electrons is made to apply to the case of protons inside the orbit of Metis. Explicit account is taken of energy loss in the Jovian ring. Comparison of the results is made with Galileo Probe measurements.

  14. DIRECTLY IMAGING TIDALLY POWERED MIGRATING JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Dong Subo; Katz, Boaz; Socrates, Aristotle [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2013-01-10

    Upcoming direct-imaging experiments may detect a new class of long-period, highly luminous, tidally powered extrasolar gas giants. Even though they are hosted by {approx} Gyr-'old' main-sequence stars, they can be as 'hot' as young Jupiters at {approx}100 Myr, the prime targets of direct-imaging surveys. They are on years-long orbits and presently migrating to 'feed' the 'hot Jupiters'. They are expected from 'high-e' migration mechanisms, in which Jupiters are excited to highly eccentric orbits and then shrink semimajor axis by a factor of {approx}10-100 due to tidal dissipation at close periastron passages. The dissipated orbital energy is converted to heat, and if it is deposited deep enough into the atmosphere, the planet likely radiates steadily at luminosity L {approx} 100-1000 L{sub Jup}(2 Multiplication-Sign 10{sup -7}-2 Multiplication-Sign 10{sup -6} L{sub Sun }) during a typical {approx} Gyr migration timescale. Their large orbital separations and expected high planet-to-star flux ratios in IR make them potentially accessible to high-contrast imaging instruments on 10 m class telescopes. {approx}10 such planets are expected to exist around FGK dwarfs within {approx}50 pc. Long-period radial velocity planets are viable candidates, and the highly eccentric planet HD 20782b at maximum angular separation {approx}0.''08 is a promising candidate. Directly imaging these tidally powered Jupiters would enable a direct test of high-e migration mechanisms. Once detected, the luminosity would provide a direct measurement of the migration rate, and together with mass (and possibly radius) estimate, they would serve as a laboratory to study planetary spectral formation and tidal physics.

  15. Hubble Gallery of Jupiter's Galilean Satellites

    Science.gov (United States)

    1995-01-01

    This is a Hubble Space Telescope 'family portrait' of the four largest moons of Jupiter, first observed by the Italian scientist Galileo Galilei nearly four centuries ago. Located approximately one-half billion miles away, the moons are so small that, in visible light, they appear as fuzzy disks in the largest ground-based telescopes. Hubble can resolve surface details seen previously only by the Voyager spacecraft in the early 1980s. While the Voyagers provided close-up snapshots of the satellites, Hubble can now follow changes on the moons and reveal other characteristics at ultraviolet and near-infrared wavelengths.Over the past year Hubble has charted new volcanic activity on Io's active surface, found a faint oxygen atmosphere on the moon Europa, and identified ozone on the surface of Ganymede. Hubble ultraviolet observations of Callisto show the presence of fresh ice on the surface that may indicate impacts from micrometeorites and charged particles from Jupiter's magnetosphere.Hubble observations will play a complementary role when the Galileo spacecraft arrives at Jupiter in December of this year.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  16. Capture of irregular satellites at Jupiter

    Energy Technology Data Exchange (ETDEWEB)

    Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2014-03-20

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10{sup –8}. This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.

  17. Structures of the Planets Jupiter and Saturn

    CERN Document Server

    Kerley, Gerald I

    2013-01-01

    New equations of state (EOS) for hydrogen, helium, and compounds containing heavier elements are used to construct models for the structures of the planets Jupiter and Saturn. Good agreement with the gravitational moments J2 and J4 is obtained with a model that uses a two-layer gas envelope, in which the inner region is denser than the outer one, together with a small, dense core. It is possible to match J2 with a homogeneous envelope, but an envelope with a denser inner region is needed to match both moments. The two-layer envelope also gives good agreement with the global oscillation data for Jupiter. In Jupiter, the boundary between the inner and outer envelopes occurs at 319 GPa, with an 8% density increase. In Saturn, it occurs at 227 GPa, with a 69% density increase. The differences between the two planets show that the need for a density increase is not due to EOS errors. It is also shown that helium enrichment cannot be the cause of the density increase. The phenomenon can be explained as the result o...

  18. Directly Imaging Tidally Powered Migrating Jupiters

    CERN Document Server

    Dong, Subo; Socrates, Aristotle

    2012-01-01

    We show that ongoing direct imaging experiments may detect a new class of long-period, highly luminous, tidally powered extrasolar gas giants. Even though they are hosted by Gyr-"old" main-sequence stars, they can be as "hot" as young Jupiters at ~100 Myr, the prime targets of direct imaging surveys. These planets, with years-long orbits, are presently migrating to "feed" the "hot Jupiters" in steady state. Their existence is expected from a class of "high-e" migration mechanisms, in which gas giants are excited to highly eccentric orbits and then shrink their semi-major axis by factor of ~ 10-100 due to tidal dissipation at successive close periastron passages. The dissipated orbital energy is converted to heat, and if it is deposited deep enough into the planet atmosphere, the planet likely radiates steadily at luminosity ~2-3 orders of magnitude larger than that of our Jupiter during a typical Gyr migration time scale. Their large orbital separations and expected high planet-to-star flux ratios in IR make ...

  19. Illuminating Hot Jupiters in caustic crossing

    CERN Document Server

    Sajadian, Sedighe

    2010-01-01

    In recent years a large number of Hot Jupiters orbiting in a very close orbit around the parent stars have been explored with the transit and doppler effect methods. Here in this work we study the gravitational microlensing effect of a binary lens on a parent star with a Hot Jupiter revolving around it. Caustic crossing of the planet makes enhancements on the light curve of the parent star in which the signature of the planet can be detected by high precision photometric observations. We use the inverse ray shooting method with tree code algorithm to generate the combined light curve of the parent star and the planet. In order to investigate the probability of observing the planet signal, we do a Monte-Carlo simulation and obtain the observational optical depth of $\\tau \\sim 10^{-8}$. We show that about ten years observations of Galactic Bulge with a network of telescopes will enable us detecting about ten Hot Jupiter with this method. Finally we show that the observation of the microlensing event in infra-re...

  20. New Horizons Imaging of Jupiter's Main Ring

    Science.gov (United States)

    Throop, Henry B.; Showalter, Mark Robert; Dones, Henry C. Luke; Hamilton, D. P.; Weaver, Harold A.; Cheng, Andrew F.; Stern, S. Alan; Young, Leslie; Olkin, Catherine B.; New Horizons Science Team

    2016-10-01

    New Horizons took roughly 520 visible-light images of Jupiter's ring system during its 2007 flyby, using the spacecraft's Long-Range Reconnaissance Imager (LORRI). These observations were taken over nine days surrounding Jupiter close-approach. They span a range in distance of 30 - 100 RJ, and a phase angle range of 20 - 174 degrees. The highest resolution images -- more than 200 frames -- were taken at a resolution approaching 20 km/pix.We will present an analysis of this dataset, much of which has not been studied in detail before. Our results include New Horizons' first quantitative measurements of the ring's intrinsic brightness and variability. We will also present results on the ring's azimuthal and radial structure. Our measurements of the ring's phase curve will be used to infer properties of the ring's dust grains.Our results build on the only previous analysis of the New Horizons Jupiter ring data set, presented in Showalter et al (2007, Science 318, 232-234), which detected ring clumps and placed a lower limit on the population of undetected ring-moons.This work was supported by NASA's OPR program.

  1. Himalia, a Small Moon of Jupiter

    Science.gov (United States)

    2001-01-01

    NASA's Cassini spacecraft captured images of Himalia, the brightest of Jupiter's outer moons, on Dec. 19, 2000, from a distance of 4.4 million kilometers (2.7 million miles).This near-infrared image, with a resolution of about 27 kilometers (17 miles) per pixel, indicates that the side of Himalia facing the spacecraft is roughly 160 kilometers (100 miles) in the up-down direction. Himalia probably has a non-spherical shape. Scientists believe it is a body captured into orbit around Jupiter, most likely an irregularly shaped asteroid.In the main frame, an arrow indicates Himalia. North is up. The inset shows the little moon magnified by a factor of 10, plus a graphic indicating Himalia's size and the direction of lighting (with sunlight coming from the left). Cassini's pictures of Himalia were taken during a brief period when Cassini's attitude was stabilized by thrusters instead of by a steadier reaction-wheel system. No spacecraft or telescope had previously shown any of Jupiter's outer moons as more than a star-like single dot.Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  2. Absorption of trapped particles by Jupiter's moons

    Science.gov (United States)

    Hess, W. N.; Birmingham, T. J.; Mead, G. D.

    1974-01-01

    Inclusion of absorption effects of the four innermost moons in the radial transport equations for electrons and protons in Jupiter's magnetosphere. It is found that the phase space density n at 2 Jupiter radii for electrons with equatorial pitch angles less than 69 deg is reduced by a factor of 42,000 when lunar absorption is included in the calculation. For protons with equatorial pitch angles less than 69 deg the corresponding reduction factor is 2,300,000. The effect of the satellites becomes progressively weaker for both electrons and protons as equatorial pitch angles of 90 deg are approached, because the likelihood of impacting a satellite becomes progressively smaller. The large density decreases found at the orbits of Io, Europa, and Ganymede result in corresponding particle flux decreases that should be observed by spacecraft making particle measurements in Jupiter's magnetosphere. The characteristic signature of satellite absorption should be a downward-pointing vertex in the flux versus radius curve at the L value corresponding to each satellite.

  3. Did Jupiter's core form in the innermost parts of the Sun's protoplanetary disk?

    CERN Document Server

    Raymond, Sean N; Bitsch, Bertram; Jacobson, Seth A

    2016-01-01

    Jupiter's core is generally assumed to have formed beyond the snow line. Here we consider an alternative scenario, that Jupiter's core may have accumulated in the innermost parts of the protoplanetary disk. A growing body of research suggests that small particles ("pebbles") continually drift inward through the disk. If a fraction of drifting pebbles is trapped at the inner edge of the disk a several Earth-mass core can quickly grow. Subsequently, the core may migrate outward beyond the snow line via planet-disk interactions. Of course, to reach the outer Solar System Jupiter's core must traverse the terrestrial planet-forming region. We use N-body simulations including synthetic forces from an underlying gaseous disk to study how the outward migration of Jupiter's core sculpts the terrestrial zone. If the outward migration is fast (Tmig~10^4 years), the core simply migrates past resident planetesimals and planetary embryos. However, if its migration is slower (Tmig~10^5 years) the core removes solids from th...

  4. Pathways of F region thermospheric mass density enhancement via soft electron precipitation

    Science.gov (United States)

    Zhang, B.; Varney, R. H.; Lotko, W.; Brambles, O. J.; Wang, W.; Lei, J.; Wiltberger, M.; Lyon, J. G.

    2015-07-01

    The efficiencies of pathways of thermospheric heating via soft electron precipitation in the dayside cusp region are investigated using the coupled magnetosphere-ionosphere-thermosphere model (CMIT). Event-based data-model comparisons show that the CMIT model is capable of reproducing the thermospheric mass density variations measured by the CHAMP satellite during both quite and active periods. During the 24 August 2005 storm event (Kp = 6-) while intense Joule heating rate occurs in the polar cusp region, including soft electron precipitation is important for accurately modeling the F region thermospheric mass density distribution near the cusp region. During the 27 July 2007 event (Kp = 2-) while little Joule heating rate occurs in the polar cusp region, the controlled CMIT simulations suggest that the direct pathway through the energy exchange between soft electrons and thermospheric neutrals is the dominant process during this event, which only has a small effect on the neutral temperature and mass density at 400 km altitude. Comparisons between the two case studies show that the indirect pathway via increasing the F region Joule heating rate is a dominant process during the 24 August 2005 storm event, which is much more efficient than the direct heating process.

  5. Variations of thermospheric composition according to AE-C data and CTIP modelling

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    2004-01-01

    Full Text Available Data from the Atmospheric Explorer C satellite, taken at middle and low latitudes in 1975-1978, are used to study latitudinal and month-by-month variations of thermospheric composition. The parameter used is the "compositional Ρ-parameter", related to the neutral atomic oxygen/molecular nitrogen concentration ratio. The midlatitude data show strong winter maxima of the atomic/molecular ratio, which account for the "seasonal anomaly" of the ionospheric F2-layer. When the AE-C data are compared with the empirical MSIS model and the computational CTIP ionosphere-thermosphere model, broadly similar features are found, but the AE-C data give a more molecular thermosphere than do the models, especially CTIP. In particular, CTIP badly overestimates the winter/summer change of composition, more so in the south than in the north. The semiannual variations at the equator and in southern latitudes, shown by CTIP and MSIS, appear more weakly in the AE-C data. Magnetic activity produces a more molecular thermosphere at high latitudes, and at mid-latitudes in summer.

    Key words. Atmospheric composition and structure (thermosphere – composition and chemistry

  6. Mars thermospheric scale height: CO Cameron and CO2+ dayglow observations from Mars Express

    Science.gov (United States)

    Stiepen, A.; Gérard, J.-C.; Bougher, S.; Montmessin, F.; Hubert, B.; Bertaux, J.-L.

    2015-01-01

    The CO Cameron (170-270 nm) and CO2+ ultraviolet doublet (298 and 299 nm) emissions have been observed on the Mars dayside with Mars Express Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument in the limb viewing mode. These ultraviolet emissions ultimately arise from the excitation of the neutral atmosphere by solar extreme ultraviolet radiation. We analyze a wide dataset covering the years 2003-2013 to determine the scale height of the thermosphere and its variability. We show under which conditions the neutral thermospheric temperature is derived from the CO Cameron and CO2+ emission topside scale height of the limb profiles. We show that emission scale heights are highly variable, ranging from 8.4 to 21.8 km and analyze possible differences between CO Cameron and CO2+-derived scale heights. These large variations appear to dominate over the long-term control exerted by the solar flux reaching the top of the atmosphere during the SPICAM observing period when solar minimum to moderate conditions prevailed. Solar heating impacting the topside thermosphere scale height is apparently overwhelmed by other forcing processes (e.g. waves and tides) during this observing period. It also appears that the crustal residual magnetic field does not significantly influence the scale height of the thermosphere. Furthermore, our analysis suggests that local variations in the thermospheric scale height and associated temperature are equal to or larger than seasonal-latitudinal variability.

  7. Circulation Changes in the Mesosphere and the Lower Thermosphere Associated with Sudden Stratospheric Warmings

    Science.gov (United States)

    Hirooka, T.; Iwao, K.

    2016-12-01

    Influences of sudden stratospheric warmings (SSWs) reach the mesosphere and the thermosphere. Recently, significant global cooling during SSWs in the thermosphere have been reported on the basis of numerical simulations. However, observational studies are insufficient for the region, so that detailed 3-dimendional structure and the dynamical mechanism are still unclear. Hence, we investigate circulation changes in the mesosphere and thermosphere along with in the stratosphere during SSWs by using TIMED/SABER satellite data and radar data. The SABER observes the atmospheric temperature field in high altitudes up to the lower thermosphere (ca. 120km). Time series of the SABER data includes tidal components, because the satellite orbit is not sun-synchronous and the local time of observation gradually decreases at a specific latitude. The perfect separation of the time series data into tidal and daily changes is difficult especially when diurnal components are amplified. Therefore, we additionally analyze the radar data at some selected stations. Resultantly, north polar temperatures during SSWs show lower thermosphere warming and mesospheric cooling along with the anti-correlated temperature changes in the wide region except over the north pole. In the presentation, we discuss further detailed features of circulation changes associated with SSWs.

  8. Optical interferometric studies of the nighttime equatorial thermosphere: Enhanced temperatures and zonal wind gradients

    Science.gov (United States)

    Meriwether, J. W.; Biondi, M. A.; Herrero, F. A.; Fesen, C. G.; Hallenback, D. C.

    1997-09-01

    Fabry-Perot interferometric observations at 630 nm of equatorial thermospheric winds and temperatures in the four cardinal directions and zenith from Arequipa, Peru, during local winter for moderate and high solar fluxes showed elevated temperatures over the Andes Mountains that persisted through the night. The difference in temperature between east and west observations was typically ~100 to 200 K for moderate flux values and as high as 400 K at solar maximum. Correlated with these localized heating regions were differences in the zonal thermospheric wind of 50 to 70 m/s for observations to the west and to the east of the Arequipa observatory. Also noted in these periods for the region over the Andes was the increased variance of the temperature values above the measurement error. These effects of increased variability and localized heating were not observed at solar minimum. The lack of a significant local time dependence in the diurnal variation of the temperature enhancements suggests that the origin of the heating cannot be related to the coupling of the electrodynamics of the ionosphere to the thermosphere. Instead the hypothesis is advanced that gravity wave energy from the surface penetrates into the thermosphere, where viscous dissipation causes the heating. Such wave activity would also explain the increased variability of the temperatures for the thermosphere regions over mountainous terrain.

  9. The asteroid belt outer region under jumping-Jupiter migration

    Science.gov (United States)

    Gaspar, H. S.; Winter, O. C.; Vieira Neto, E.

    2017-09-01

    The radial configuration of the outer region of the main asteroid belt is quite peculiar, and has much to say about the past evolution of Jupiter. In this work, we investigate the dynamical effects of a jumping-Jupiter-like migration over a more extended primordial asteroid belt. Jupiter's migrations are simulated using a fast jumping-Jupiter synthesizer. Among the results, we highlight non-negligible fractions of primordial objects trapped in 3:2 and 4:3 mean motion resonances (MMRs) with Jupiter. They survived the whole truculent phase of migration and originated populations that are like Hildas and Thules. Fractions ranging from 3 to 6 per cent of the initial distribution remained trapped in 3:2 MMR, and at least 0.05 per cent in 4:3. These results show that the resonance trapping of primordial objects may have originated these resonant populations. This theory is consistent even for Jupiter's truculent evolution.

  10. Thermospheric mass density measurement from precise orbit ephemeris

    Directory of Open Access Journals (Sweden)

    Junyu Chen

    2016-05-01

    Full Text Available Atmospheric drag, which can be inferred from orbit information of low-Earth orbiting (LEO satellites, provides a direct means of measuring mass density. The temporal resolution of derived mass density could be in the range from minutes to days, depending on the precision of the satellite orbit data. This paper presents two methods potentially being able to estimate thermosphere mass density from precise obit ephemeris with high temporal resolution. One method is based on the drag perturbation equation of the semi-major axis and the temporal resolution of retrieved density could be 150 s for CHAMP satellite. Another method generates corrections to densities computed from a baseline density model through a Kalman filter orbit drag coefficient determination (KFOD process and the temporal resolution of derived density could be as high as 30 s for CHAMP satellite. The densities estimated from these two methods are compared with densities obtained from accelerometer data of CHAMP satellite. When the accelerometer data based densities are used as reference values, the mean relative accuracy of the densities derived from precision orbit data using the two methods is within approximately 10%. An application of the derived densities shows that the derived densities can reduce orbit predication errors.

  11. Silicon chemistry in the mesosphere and lower thermosphere

    Science.gov (United States)

    Gómez‐Martín, Juan Carlos; Feng, Wuhu; Janches, Diego

    2016-01-01

    Abstract Silicon is one of the most abundant elements in cosmic dust, and meteoric ablation injects a significant amount of Si into the atmosphere above 80 km. In this study, a new model for silicon chemistry in the mesosphere/lower thermosphere is described, based on recent laboratory kinetic studies of Si, SiO, SiO2, and Si+. Electronic structure calculations and statistical rate theory are used to show that the likely fate of SiO2 is a two‐step hydration to silicic acid (Si(OH)4), which then polymerizes with metal oxides and hydroxides to form meteoric smoke particles. This chemistry is then incorporated into a whole atmosphere chemistry‐climate model. The vertical profiles of Si+ and the Si+/Fe+ ratio are shown to be in good agreement with rocket‐borne mass spectrometric measurements between 90 and 110 km. Si+ has consistently been observed to be the major meteoric ion around 110 km; this implies that the relative injection rate of Si from meteoric ablation, compared to metals such as Fe and Mg, is significantly larger than expected based on their relative chondritic abundances. Finally, the global abundances of SiO and Si(OH)4 show clear evidence of the seasonal meteoric input function, which is much less pronounced in the case of other meteoric species. PMID:27668138

  12. Thermospheric mass density measurement from precise orbit ephemeris

    Institute of Scientific and Technical Information of China (English)

    Junyu Chen; Jizhang Sang

    2016-01-01

    Atmospheric drag,which can be inferred from orbit information of low-Earth orbiting (LEO)satellites,provides a direct means of measuring mass density.The temporal resolution of derived mass density could be in the range from minutes to days,depending on the precision of the satellite orbit data.This paper presents two methods potentially being able to estimate thermosphere mass density from precise obit ephemeris with high temporal resolution.One method is based on the drag perturbation equation of the semi-major axis and the temporal resolution of retrieved density could be 150 s for CHAMP satellite.Another method generates corrections to densities computed from a baseline density model through a Kalman filter orbit drag coefficient determination (KFOD) process and the temporal resolution of derived density could be as high as 30 s for CHAMP satellite.The densities estimated from these two methods are compared with densities obtained from accelerometer data of CHAMP satellite.When the accelerometer data based densities are used as reference values,the mean relative accuracy of the densities derived from precision orbit data using the two methods is within approximately 10%.An application of the derived densities shows that the derived densities can reduce orbit predication errors.

  13. Extended Heat Deposition in Hot Jupiters: Application to Ohmic Heating

    CERN Document Server

    Ginzburg, Sivan

    2015-01-01

    Many giant exoplanets in close orbits have observed radii which exceed theoretical predictions. One suggested explanation for this discrepancy is heat deposited deep inside the atmospheres of these "hot Jupiters". Here, we study extended power sources which distribute heat from the photosphere to the deep interior of the planet. Our analytical treatment is a generalization of a previous analysis of localized "point sources". We model the deposition profile as a power law in the optical depth and find that planetary cooling and contraction halt when the internal luminosity (i.e. cooling rate) of the planet drops below the heat deposited in the planet's convective region. A slowdown in the evolutionary cooling prior to equilibrium is possible only for sources which do not extend to the planet's center. We estimate the Ohmic dissipation resulting from the interaction between the atmospheric winds and the planet's magnetic field, and apply our analytical model to Ohmically heated planets. Our model can account fo...

  14. Core Deuterium Fusion and Radius Inflation in Hot Jupiters

    Science.gov (United States)

    Jaikumar, Prashanth; Rachid Ouyed

    2016-06-01

    Several laboratory-based studies have shown that the Deuterium fusion cross-section is enhanced in a solid deuterated target as compared to a gas target, attributable to enhanced mobility of deuterons in a metal lattice. As an application, we propose that, for core temperatures and compositions characterizing hot Jupiters, screened Deuterium fusion can occur deep in the interior, and show that the amount of radius inflation from this effect can be important if there is sufficient rock-ice in the core. The mechanism of screened Deuterium fusion, operating in the above temperature range, is generally consistent with the trend in radius anomaly with planetary equilibrium temperature. We also explore the trend with planetary mass using a simple analytic model.

  15. Study of Power Options for Jupiter and Outer Planet Missions

    Science.gov (United States)

    Landis, Geoffrey A.; Fincannon, James

    2015-01-01

    Power for missions to Jupiter and beyond presents a challenging goal for photovoltaic power systems, but NASA missions including Juno and the upcoming Europa Clipper mission have shown that it is possible to operate solar arrays at Jupiter. This work analyzes photovoltaic technologies for use in Jupiter and outer planet missions, including both conventional arrays, as well as analyzing the advantages of advanced solar cells, concentrator arrays, and thin film technologies. Index Terms - space exploration, spacecraft solar arrays, solar electric propulsion, photovoltaic cells, concentrator, Fresnel lens, Jupiter missions, outer planets.

  16. The Role of Solar Neutrinos in the Jupiter

    CERN Document Server

    Burov, Valery

    2008-01-01

    Judging from the fact that the planet Jupiter is bigger in size than the Earth by 10^3 while is smaller than the Sun by 10^3 and that the average distance of the Jupiter from the Sun is 5.203 a.u., the solar neutrinos, when encounter the Jupiter, may have some accumulating effects bigger than on the Earth. We begin by estimating how much energy/power carried by solar neutrinos get transferred by this unique process, to confirm that solar neutrinos, despite of their feeble neutral weak current interactions, might deposit enough energy in the Jupiter. We also speculate on the other remarkable effects.

  17. TIMED Doppler Interferometer on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite: Data product overview

    Science.gov (United States)

    Niciejewski, R.; Wu, Q.; Skinner, W.; Gell, D.; Cooper, M.; Marshall, A.; Killeen, T.; Solomon, S.; Ortland, D.

    2006-11-01

    The TIMED Doppler Interferometer (TIDI) performs the measurement of upper atmospheric winds on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. This is an optimized single etalon Fabry Perot interferometer that records the slight Doppler shift of individual emission features of the O2 (0,0) atmospheric band. The interferometer operates at a 100% duty cycle obtaining neutral wind altitude profiles on a global basis. The measurements are synoptic and provide an uninterrupted long-term climatological record of the dynamics in the mesosphere and lower thermosphere regions. The data products from TIDI include (1) apparent line of sight winds and integrated brightness, (2) inverted line of sight winds and volume emission rate, and (3) inverted horizontal neutral wind fields on an evenly spaced track angle/altitude grid. The data products demonstrate an interannual variability in the tidal structure of the mesosphere and the lower thermosphere and an inherent daily geophysical variance.

  18. The responses of the thermosphere due to a geomagnetic storm: A MHD model

    Science.gov (United States)

    Wu, S. T.; Chang, S.

    1972-01-01

    A magnetohydrodynamics theory was used to study the dynamic response of the neutral atmosphere to a geomagnetic storm. A full set of magnetohydrodynamic equations appropriate for the present problem is derived and their various orders of approximation are discussed in some detail. In order to demonstrate the usefulness of this theoretical model, the May 1967 geomagnetic storm data were used in the resulting set of nonlinear, time dependent, partial differential magnetohydrodynamic equations to calculate variations of the thermosphere due to the storm. The numerical results are presented for wind speeds, electric field strength, and amount of joule heating at a constant altitude for the data recorded. Data show that the strongest thermospheric responses are at the polar region becoming weaker in the equatorial region. This may lead to the speculation that a thermospheric wave is generated in the polar region due to the geomagnetic storm which propagates towards the equator.

  19. High time resolution measurements of the thermosphere from Fabry-Perot Interferometer measurements of atomic oxygen

    Directory of Open Access Journals (Sweden)

    E. A. K. Ford

    2007-06-01

    Full Text Available Recent advances in the performance of CCD detectors have enabled a high time resolution study of the high latitude upper thermosphere with Fabry-Perot Interferometers (FPIs to be performed. 10-s integration times were used during a campaign in April 2004 on an FPI located in northern Sweden in the auroral oval. The FPI is used to study the thermosphere by measuring the oxygen red line emission at 630.0 nm, which emits at an altitude of approximately 240 km. Previous time resolutions have been 4 min at best, due to the cycle of look directions normally observed. By using 10 s rather than 40 s integration times, and by limiting the number of full cycles in a night, high resolution measurements down to 15 s were achievable. This has allowed the maximum variability of the thermospheric winds and temperatures, and 630.0 nm emission intensities, at approximately 240 km, to be determined as a few minutes. This is a significantly greater variability than the often assumed value of 1 h or more. A Lomb-Scargle analysis of this data has shown evidence of gravity wave activity with waves with short periods. Gravity waves are an important feature of mesosphere-lower thermosphere (MLT dynamics, observed using many techniques and providing an important mechanism for energy transfer between atmospheric regions. At high latitudes gravity waves may be generated in-situ by localised auroral activity. Short period waves were detected in all four clear nights when this experiment was performed, in 630.0 nm intensities and thermospheric winds and temperatures. Waves with many periodicities were observed, from periods of several hours, down to 14 min. These waves were seen in all parameters over several nights, implying that this variability is a typical property of the thermosphere.

  20. The Split-field Etalon Doppler Imager (SEDI) - A Compact Thermosphere Wind Profiler

    Science.gov (United States)

    Marchant, A.; Whalen, S.; Stromberg, E. M.; Swenson, C.; Fish, C. S.

    2012-12-01

    The dynamics of the Earth's thermosphere remains an important target for scientific exploration. The primary energy input is solar EUV but during solar events additional energy is deposited into the high-latitude thermosphere in the form of Joule heating and particle precipitation, driving global changes in thermosphere temperature profiles and circulation. Thermosphere wind and temperature profiles are important factors for understanding the dynamic response of the earth system to solar storms, for building and maintaining global weather and climate models, and for making operational space weather predictions. We report progress in miniaturized sensor technology for orbital monitoring of wind and neutral temperature profiles in the upper thermosphere, 200 - 350 km. These profiles are sensed using the atomic oxygen airglow at 630.0 nm. The split-field etalon Doppler imager (SEDI) focuses forward and aft scenes of the earth limb onto a single EMCCD focal plane through a single Fabry-Perot etalon (Figure 1). The size of the SEDI optical system is 14 x 18 x 7 cm. The instrument has no moving parts and is easily packaged in a 6U CubeSat. Strips of the dual interferogram are analyzed with respect to fringe width and radial phase to yield profiles of the neutral temperature and Doppler shift. Instrument calibration is maintained on-orbit using the 630.4 nm reference line from a neon glow lamp. The prediction of Doppler sensitivity vs. tangent height against the limb is plotted in Figure 2 for a profiling resolution of 5 km. Forward-view Doppler profiles are combined with aft-view profiles collected approximately 5 minutes later to create localized 2D wind profiles. A constellation of SEDI CubeSats could provide global monitoring of the thermosphere wind field and its dynamics.; Figure 1. Layout of the SEDI instrument. ; Figure 2. Doppler sensitivity of the SEDI instrument.

  1. Thermospheric wind and temperature fields observed using two ground based all-sky imaging Fabry-Perot spectrometers in Antarctica

    Science.gov (United States)

    Conde, M.; Bristow, W. A.; Hampton, D. L.; Kosch, M. J.; Ishii, M.; Paxton, L. J.; Davies, T.

    2016-12-01

    During the austral summer of 2015-2016 two new all-sky imaging Fabry-Perot spectrometers were installed in Antarctica to measure wind and temperature fields in the lower and middle thermosphere, at heights spanning a range from approximately 110 to 240 km altitude. The instruments are located at McMurdo and South Pole stations, both of which are typically near the equatorward edge of the polar cap under quiet to moderate levels of activity. Automated nightly observations began in March (McMurdo) and April (South Pole) of 2016. The instruments record Doppler spectra of the thermospheric oxygen 558 nm green line and 630 nm red line emissions. They view the sky down to around 70 degrees zenith angle, with this field being divided in software into 115 sub-regions, each of which gives an independent measure of Doppler temperature and line-of-sight wind. Typical integration times are one to several minutes. Here we will present an overview of the results obtained during this first season, including both climatological averages and examples of data from individual days. The overall behavior is generally as expected, with winds blowing approximately antisunward at all local times. However substantial local perturbations about this mean flow occur frequently, and are seen to be collocated with regions of strong ion convection observed by the SuperDARN radar network, and with regions of bright aurora, as observed by the Fabry-Perot instruments themselves, and by the SSUSI instruments aboard the DMSP F16 to F18 satellites. F-region neutral temperatures recorded on most days are spatially uniform and slowly varying in time. However very significant spatial and temporal temperature variations are observed during times of geomagnetic disturbance. Wave activity is also very a very common feature of the observed wind fields. These results are morphologically quite different to the behavior seen by similar instruments located in the northern hemisphere auroral zone. Reasons for

  2. Measurements of Mesosphere and Lower Thermosphere Winds by the TIMED Doppler Interferometer

    Science.gov (United States)

    Killeen, T. L.; Gablehouse, R. D.; Johnson, R. M.; Wu, Q.; Solomon, S. C.; Gell, D. A.; Niciejewski, R. J.; Skinner, W. R.; Kafkalidis, J. F.; Ortland, D. A.

    2002-12-01

    Since the launch of the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite in December 2001, the TIMED Doppler Interferometer (TIDI) has been measuring the global wind field in the mesosphere and lower thermosphere. Validation of these data using ground-based and other space-based observations is in progress. Early analyses have focused on wind measurements in the 60 to 110 km altitude region using emissions from the O2 Atmospheric (0-0) band. We will present results showing the variability of tidal oscillations in the middle atmosphere, and new measurements of polar mesopause dynamics.

  3. Jupiter internal structure: the effect of different equations of state

    Science.gov (United States)

    Miguel, Y.; Guillot, T.; Fayon, L.

    2016-12-01

    Context. Heavy elements, even though they are a smaller constituent, are crucial to understand the formation history of Jupiter. Interior models are used to determine the amount of heavy elements in the interior of Jupiter, but this range is still subject to degeneracies because of the uncertainties in the equations of state. Aims: Before Juno mission data arrive, we present optimized calculations for Jupiter that explore the effect of different model parameters on the determination of the core and the mass of heavy elements of Jupiter. We compare recently published equations of state. Methods: The interior model of Jupiter was calculated from the equations of hydrostatic equilibrium, mass, and energy conservation, and energy transport. The mass of the core and heavy elements was adjusted to match the observed radius and gravitational moments of Jupiter. Results: We show that the determination of the interior structure of Jupiter is tied to the estimation of its gravitational moments and the accuracy of equations of state of hydrogen, helium, and heavy elements. Locating the region where helium rain occurs and defining its timescale is important to determine the distribution of heavy elements and helium in the interior of Jupiter. We show that the differences found when modeling the interior of Jupiter with recent EOS are more likely due to differences in the internal energy and entropy calculation. The consequent changes in the thermal profile lead to different estimates of the mass of the core and heavy elements, which explains differences in recently published interior models of Jupiter. Conclusions: Our results help clarify the reasons for the differences found in interior models of Jupiter and will help interpreting upcoming Juno data. Full appendix tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A114

  4. Space Weathering Perspectives on Europa Amidst the Tempest of the Jupiter Magnetospheric System

    Science.gov (United States)

    Cooper, J. F.; Hartle, R. E.; Lipatov, A. S.; Sittler, E. C.; Cassidy, T. A.; Ip. W.-H.

    2010-01-01

    Europa resides within a "perfect storm" tempest of extreme external field, plasma, and energetic particle interactions with the magnetospheric system of Jupiter. Missions to Europa must survive, functionally operate, make useful measurements, and return critical science data, while also providing full context on this ocean moon's response to the extreme environment. Related general perspectives on space weathering in the solar system are applied to mission and instrument science requirements for Europa.

  5. JUPITER and satellites: Clinical implications of the JUPITER study and its secondary analyses.

    Science.gov (United States)

    Kostapanos, Michael S; Elisaf, Moses S

    2011-07-26

    THE JUSTIFICATION FOR THE USE OF STATINS IN PREVENTION: an intervention trial evaluating rosuvastatin (JUPITER) study was a real breakthrough in primary cardiovascular disease prevention with statins, since it was conducted in apparently healthy individuals with normal levels of low-density lipoprotein cholesterol (LDL-C JUPITER, rosuvastatin was associated with significant reductions in cardiovascular outcomes as well as in overall mortality compared with placebo. In this paper the most important secondary analyses of the JUPITER trial are discussed, by focusing on their novel findings regarding the role of statins in primary prevention. Also, the characteristics of otherwise healthy normocholesterolemic subjects who are anticipated to benefit more from statin treatment in the clinical setting are discussed. Subjects at "intermediate" or "high" 10-year risk according to the Framingham score, those who exhibit low post-treatment levels of both LDL-C (JUPITER added to our knowledge that statins may be effective drugs in the primary prevention of cardiovascular disease in normocholesterolemic individuals at moderate-to-high risk. Also, statin treatment may reduce the risk of venous thromboembolism and preserve renal function. An increase in physician-reported diabetes represents a major safety concern associated with the use of the most potent statins.

  6. Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

    Science.gov (United States)

    Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J.-L.; Bruzzone, L.; Kofman, W.

    2012-02-01

    Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5 and 50 MHz. Part of this frequency range overlaps with that of the natural jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emissions are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

  7. CAPTURE OF TROJANS BY JUMPING JUPITER

    Energy Technology Data Exchange (ETDEWEB)

    Nesvorny, David [Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 (United States); Vokrouhlicky, David [Institute of Astronomy, Charles University, V Holesovickach 2, 180 00 Prague 8 (Czech Republic); Morbidelli, Alessandro [Departement Cassiopee, University of Nice, CNRS, Observatoire de la Cote d' Azur, Nice, F-06304 (France)

    2013-05-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to {approx}5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) Multiplication-Sign 10{sup -7} for each particle in the original transplanetary disk, implying that the disk contained (3-4) Multiplication-Sign 10{sup 7} planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M{sub disk} {approx} 14-28 M{sub Earth}, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

  8. A Possibly Universal Red Chromophore for Jupiter

    Science.gov (United States)

    Sromovsky, Lawrence A.; Baines, Kevin; Fry, Patrick M.

    2016-10-01

    A new laboratory-generated chemical compound made from photodissociated ammonia (NH3) molecules reacting with acetylene (C2H2) was suggested as a possible coloring agent for Jupiter's Great Red Spot (GRS) by Carlson et al. (2016, Icarus 274, 106-115). Baines et al. (2016, AAS/DPS Meeting abstract) showed that the GRS spectrum measured by the visual channels of the Cassini VIMS instrument in 2000 could be accurately fit by a cloud model in which the chromophore appeared as small particles in a physically thin layer immediately above the main cloud layer of the GRS. Here we show that the same chromophore and similar layer structure can also provide close matches to the 0.4-1 micron spectra of many other cloud features on Jupiter, suggesting that this material may be a nearly universal chromophore responsible for the various degrees of red coloration on Jupiter. This is a robust conclusion, even for 12 percent changes in VIMS calibration and large uncertainties in the refractive index of the main cloud layer due to uncertain fractions of NH4SH and NH3 in its cloud particles. The chromophore layer can account for color variations among north and south equatorial belts, equatorial zone, and the Great Red Spot, by varying particle size from 0.12 to 0.29 micron and optical depth from 0.06 to 0.76. The total mass of the chromophore layer is much less variable than its optical depth, staying mainly within 6-10 micrograms/cm2 range, but is only about half that amount in the equatorial zone. We also found a depression of the ammonia volume mixing ratio in the two belt regions, which averaged 0.4-0.5 × 10-4 immediately below the ammonia condensation level, while the other regions averaged twice that value.LAS and PMF acknowledge support from NASA Grant NNX14AH40G.

  9. Auroral ionospheric and thermospheric measurements using the incoherent scatter technique

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, W. (CEPHAG, St. Martin (France))

    1992-11-01

    The incoherent scatter technique has been applied since 1965 to study the ionosphere and thermosphere in different regions of the Earth. The analysis of the received signal gives access to several ionospheric parameters as a function of height: electron density, electron and ion temperatures and ion velocity. The derivation of these parameters is usually a complicated mathematical procedure that requires a non-linear regression program. A lot of research has been done in the ionospheric and atmospheric science using this technique. In this paper we describe how one derives the ion-neutral collision frequency and the ion composition parameters. It is usually difficult to retrieve these parameters with the incoherent scatter technique; as a result, in the standard data analysis procedure, an ionospheric model is used instead. However the numerical values chosen in the model have an influence on the other derived parameters. For instance the choice of a wrong ion composition leads to erroneous plasma temperatures. It is therefore important to assess by how much the standard procedure deviates from reality. For this reason we compare the ion composition and collision frequency retrieved from a sophisticated analysis scheme with the values that are derived from models under similar geophysical conditions. It is also possible to derive from the observed ionospheric parameters the neutral concentrations, temperatures and winds, by using the energy and momentum equations for the ions and the neutrals. In this paper the different methods and the corresponding assumptions involved in the data analysis are discussed. We describe the influence of the frictional heating, of the vertical neutral wind and of the ionospheric perturbations on the derivation of the neutral atmospheric parameters. Our discussion of the processes involved are drawn from results obtained by Chatanika, Sondrestrom and EISCAT radars.

  10. Longitudinal and geomagnetic activity modulation of the equatorial thermosphere anomaly

    Science.gov (United States)

    Lei, Jiuhou; Thayer, Jeffrey P.; Forbes, Jeffrey M.

    2010-08-01

    In this paper we examine the detailed similarities and differences between the equatorial thermosphere anomaly (ETA) and the equatorial ionization anomaly (EIA) from 20 March to 6 April 2002, when both the ETA and the EIA are distinct in the Challenging Minisatellite Payload (CHAMP) observations. The characteristics of the ETA and the EIA are obtained from the CHAMP accelerometer, in situ electron density measurements, and total electron content (TEC) above the CHAMP satellite. Our results show that the trough locations of the ETA and the EIA in latitude show a good agreement, and both correspond well with the dip magnetic equator, while the ETA crests are usually located poleward of the EIA. Meanwhile, the latitudinal locations of the ETA crests exhibit strong hemispheric asymmetry and large variability during our study interval. The longitudinal variations between the EIA and the ETA show significant differences. The EIA crests from the CHAMP observations show strong wave 4 structures, but the primary component in the ETA is wave 1. Moreover, the ETA densities show strong variations in response to geomagnetic activity, whereas CHAMP in situ electron densities and TEC at the EIA do not reflect such large day-to-day variability. Therefore, a simple EIA-ETA relationship cannot explain the dependence of the longitudinal and geomagnetic activity modulation of the ETA and the EIA. The meridional ion drag, which is significantly modulated by enhanced equatorward winds during elevated geomagnetic activity, is probably responsible for some of the observed features in the ETA, although no unambiguous explanation for ETA formation yet exists.

  11. Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM (Europa Jupiter System Mission)

    Science.gov (United States)

    Sasaki, Sho; Fujimoto, Masaki; Takashima, Takeshi; Yano, Hajime; Kasaba, Yasumasa; Takahashi, Yukihiro; Kimura, Jun; Tsuda, Yuichi; Funase, Ryu; Mori, Osamu

    2010-05-01

    Europa Jupiter System Mission (EJSM) is an international mission to explore and Jupiter, its satellites and magnetospheric environment in 2020s. EJSM consists of (1) The Jupiter Europa Orbiter (JEO) by NASA, (2) the Jupiter Ganymede Orbiter (JGO) by ESA, and (3) the Jupiter Magnetospheric Orbiter (JMO) studied by JAXA (Japan Aerospace Exploration Agency). In February 2009, NASA and ESA decided to continue the study of EJSM as a candidate of the outer solar system mission. JMO will have magnetometers, low-energy plasma spectrometers, medium energy particle detectors, energetic particle detectors, electric field / plasma wave instruments, an ENA imager, an EUV spectrometer, and a dust detector. Collaborating with plasma instruments on board JEO and JGO, JMO will investigate the fast and huge rotating magnetosphere to clarify the energy procurement from Jovian rotation to the magnetosphere, to clarify the interaction between the solar wind the magnetosphere. Especially when JEO and JGO are orbiting around Europa and Ganymede, respectively, JMO will measure the outside condition in the Jovian magnetosphere. JMO will clarify the characteristics of the strongest accelerator in the solar system with the investigation of the role of Io as a source of heavy ions in the magnetosphere. JAXA started a study of a solar power sail for deep space explorations. Together with a solar sail (photon propulsion), it will have very efficient ion engines where electric power is produced solar panels within the sail. JAXA has already experienced ion engine in the successful Hayabusa mission, which was launched in 2003 and is still in operation in 2010. For the purpose of testing solar power sail technology, an engineering mission IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) will be launched in 2010 together with Venus Climate Orbiter PLANET-C. The shape of the IKAROS' membrane is square, with a diagonal distance of 20m. It is made of polyimide film only 0.0075mm

  12. Jupiter Europa Orbiter Architecture Definition Process

    Science.gov (United States)

    Rasmussen, Robert; Shishko, Robert

    2011-01-01

    The proposed Jupiter Europa Orbiter mission, planned for launch in 2020, is using a new architectural process and framework tool to drive its model-based systems engineering effort. The process focuses on getting the architecture right before writing requirements and developing a point design. A new architecture framework tool provides for the structured entry and retrieval of architecture artifacts based on an emerging architecture meta-model. This paper describes the relationships among these artifacts and how they are used in the systems engineering effort. Some early lessons learned are discussed.

  13. Comparative impactology on Jupiter: Cataloging the clumps

    Science.gov (United States)

    Wong, Michael

    2010-09-01

    Seven months after HubbleA?s first servicing mission, the impact of Comet Shoemaker-Levy 9 {SL9} captured worldwide attentionA?and the newly-installed WFPC2 captured 472 images of Jupiter in Program 5642. We will complete a census of each impact, including evolution, size, morphology, and color, now that the geometric and photometric calibration of WFPC2 has reached its best and final state. The data from Program 5642 prove their great value by still continuing to generate science publications, and we will upload deprojected {latitude-longitude mapped} data as High Level Science Products to further enhance the usability of this unique data set. The WFPC2 data are needed to understand recent observations of the 2009 impact on Jupiter, in which only 36 WFC3 and ACS images were obtained in Program 12003. In the isolated 2009 impact, the debris formed clumps that lasted at least until Jupiter was imaged again on 22 September {Program 11559}, two months after the impact. Clumps were observed in a subset of SL9 impact sites, but a complete survey of all the available WFPC2 impact site imaging data will enable us to measure clump formation, favored dynamical environments, frequency of occurrence, interactions with other Jovian atmospheric features, and rates of change in size and albedo. Based on the 2009 WFC3 and ACS data, we suggest that these clumps are lower stratospheric eddies that maintain aerosol concentrations against dissipation. We will search the proposed complete catalog of 1994 WFPC2 data to isolate the determining factors for the formation and evolution of these clumps, with the goal of finding out whether they are commonplace Jovian dynamical features simply traced by impact-generated aerosols, or unique features generated by the impacts themselves {either through impact-related thermochemical processes, or through differences in particle microphysics}. If the clumps mark commonplace but normally invisible eddies, they may play interesting roles in the

  14. Can Terrestrial Planets Form in Hot-Jupiter Systems?

    CERN Document Server

    Fogg, Martyn J

    2007-01-01

    Models of terrestrial planet formation in the presence of a migrating giant planet have challenged the notion that hot-Jupiter systems lack terrestrial planets. We briefly review this issue and suggest that hot-Jupiter systems should be prime targets for future observational missions designed to detect Earth-sized and potentially habitable worlds.

  15. Forum on Concepts and Approaches for Jupiter Icy Moons Orbiter

    Science.gov (United States)

    2003-01-01

    The papers presented at this conference primarily discuss instruments and techniques for conducting science on Jupiter's icy moons, and geologic processes on the moons themselves. Remote sensing of satellites, cratering on satellites, and ice on the surface of Europa are given particular attention. Some papers discuss Jupiter's atmosphere, or exobiology.

  16. Coupled evolutions of the stellar obliquity, orbital distance, and planet's radius due to the Ohmic dissipation induced in a diamagnetic hot Jupiter around a magnetic T Tauri star

    CERN Document Server

    Chang, Yu-Ling; Gu, Pin-Gao

    2012-01-01

    We revisit the calculation of the Ohmic dissipation in a hot Jupiter presented in Laine et al. (2008) by considering more realistic interior structures, stellar obliquity, and the resulting orbital evolution. In this simplified approach, the young hot Jupiter of one Jupiter mass is modelled as a diamagnetic sphere with a finite resistivity, orbiting across tilted stellar magnetic dipole fields in vacuum. Since the induced Ohmic dissipation occurs mostly near the planet's surface, we find that the dissipation is unable to significantly expand the young hot Jupiter. Nevertheless, the planet inside a small co-rotation orbital radius can undergo orbital decay by the dissipation torque and finally overfill its Roche lobe during the T Tauri star phase. The stellar obliquity can evolve significantly if the magnetic dipole is parallel/anti-parallel to the stellar spin. Our results are validated by the general torque-dissipation relation in the presence of the stellar obliquity. We also run the fiducial model in Laine...

  17. Nonmigrating tidal impact on the CO2 15 μm infrared cooling of the lower thermosphere over one solar cycle

    Science.gov (United States)

    Nischal, N.; Oberheide, J.; Mlynczak, M. G.; Hunt, L. A.; Maute, A. I.

    2016-12-01

    This paper explores the impact of solar nonmigrating tides that begin near the surface as latent heat is released by tropospheric convection on the 15 μm CO2 infrared cooling of the lower thermosphere over a solar cycle. Cooling rates of CO2 observed by SABER/TIMED are analyzed on two important nonmigrating tides, DE2 and DE3. Relative amplitudes are on the order of 15-60% with respect to monthly means, depending on the season. Supporting photochemical modeling using tides from CTMT and backgrounds from various data sources reproduces the general amplitude structures and phases. Although using SABER backgrounds in photochemical modeling reproduce comparatively better structures, the general results are independent of the choice of background. The main tidal coupling mechanism is the temperature dependence of the collisional excitation of the CO2 (01101) fundamental band transition (ν2). However, the response to neutral density variations become as important as temperature above 115 km and as such explains an unexpected DE3 phase behavior in the observation. The contribution of vertical advection is comparatively small. The paper also discusses how the relative importance of the tidal coupling mechanisms changes as a function of latitude and solar cycle, in order to fully quantify the response of the CO2 15 μm infrared cooling of the lower thermosphere to tropospheric tides.

  18. Periodic changes of the activity of processes in Jupiter's atmosphere

    Science.gov (United States)

    Vidmachenko, A. P.

    2016-10-01

    Variations of the Earth jovimagnetic latitude on Jupiter are preferred in solar-driven changes of reflective properties of clouds and haze on Jupiter. Because of the orbit eccentricity (e=0,048450) the northern hemisphere receives 21% greater solar energy flow to the atmosphere, because Jupiter is in the perihelia near the time of the summer solstice. Results of our studies showed that the ratio of the brightness of the northern and southern tropical and temperate regions is evident factor of the photometric activity of the Jupiter's atmospheric processes. The obtained from the analysis of observational data for the period from 1962 to 2015 existence of variations of activity factor of the planet hemispheres with a period of 11.86 years has allowed us to talk about an existence of the seasonal reconstruction of the physical parameters of Jupiter's atmosphere.

  19. Morphological features and variations of temperature in the upper thermosphere simulated by a whole atmosphere GCM

    Directory of Open Access Journals (Sweden)

    H. Fujiwara

    2010-02-01

    Full Text Available In order to illustrate morphological features and variations of temperature in the upper thermosphere, we performed numerical simulations with a whole atmosphere general circulation model (GCM for the solar minimum and geomagnetically quiet conditions in March, June, September, and December. In previous GCMs, tidal effects were imposed at the lower boundaries assuming dominant diurnal and semi-diurnal tidal modes. Since the GCM used in the present study covers all the atmospheric regions, the atmospheric tides with various modes are generated within the GCM. The global temperature distributions obtained from the GCM are in agreement with ones obtained from NRLMSISE-00. In addition, the GCM also represents localised temperature structures which are superimposed on the global day-night distributions. These localised structures, which vary from hour to hour, would be observed as variations with periods of about 2–3 h at a single site. The amplitudes of the 2–3 h variations are significant at high-latitude, while the amplitudes are small at low-latitude. The diurnal temperature variation is more clearly identified at low-latitude than at high-latitude. When we assume the same high-latitude convection electric field in each month, the temperature calculated in the polar cap region shows diurnal variation more clearly in winter than in summer. The midnight temperature maximum (MTM, which is one of the typical low-latitude temperature structures, is also seen in the GCM results. The MTMs in the GCM results show significant day-to-day variation with amplitudes of several 10s to about 150 K. The wind convergence and stream of warm air are found around the MTM. The GCM also represent the meridional wind reversals and/or abatements which are caused due to local time variations of airflow pattern in the low-latitude region.

  20. Medium-scale gravity wave activity in the thermosphere inferred from GOCE data

    Science.gov (United States)

    Garcia, Raphael F.; Bruinsma, Sean; Massarweh, Lotfi; Doornbos, Eelco

    2016-08-01

    This study is focused on the effect of solar flux conditions on the dynamics of gravity waves (GWs) in the thermosphere. Air density and crosswind in situ estimates from the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) accelerometers are analyzed for the whole mission duration. The analysis is performed in the Fourier spectral domain averaging spectral results over periods of 2 months close to solstices. A new GW marker (called Cf3) is introduced here to characterize GWs activity under low, medium, and high solar flux conditions, showing a clear solar damping effect on GW activity. Most GW signal is found in a spectral range above 8 mHz in GOCE data, meaning a maximum horizontal wavelength of around 1000 km. The level of GW activity at GOCE altitude is strongly decreasing with increasing solar flux. Furthermore, a shift in the dominant frequency with solar flux conditions has been noted, leading to larger horizontal wavelengths (from 200 to 500 km) during high solar flux conditions. The correlation between air density variability and GW marker allows to identify most of the large-amplitude perturbations below 67° latitudes as due to GWs. The influence of correlated error sources, between air density and crosswinds, is discussed. Consistency of the spectral domain results is verified in the time domain with a global mapping of high-frequency air density perturbations along the GOCE orbit. This analysis shows a clear dependence with geomagnetic latitude with strong perturbations at magnetic poles and an extension to lower latitudes favored by low solar activity conditions. These results are consistent with previous Challenging Minisatellite Payload (CHAMP) data analysis and with general circulation models.

  1. Elliptical instability in hot Jupiter systems

    CERN Document Server

    Cébron, David; Gal, Patrice Le; Moutou, Claire; Leconte, J; Sauret, Alban

    2013-01-01

    Several studies have already considered the influence of tides on the evolution of systems composed of a star and a close-in companion to tentatively explain different observations such as the spin-up of some stars with hot Jupiters, the radius anomaly of short orbital period planets and the synchronization or quasi-synchronization of the stellar spin in some extreme cases. However, the nature of the mechanism responsible for the tidal dissipation in such systems remains uncertain. In this paper, we claim that the so-called elliptical instability may play a major role in these systems, explaining some systematic features present in the observations. This hydrodynamic instability, arising in rotating flows with elliptical streamlines, is suspected to be present in both planet and star of such systems, which are elliptically deformed by tides. The presence and the influence of the elliptical instability in gaseous bodies, such as stars or hot Jupiters, are most of the time neglected. In this paper, using numeri...

  2. Fading of Jupiter's South Equatorial Belt

    Science.gov (United States)

    Sola, Michael A.; Orton, Glenn; Baines, Kevin; Yanamandra-Fisher, Padma

    2011-01-01

    One of Jupiter's most dominant features, the South Equatorial Belt, has historically gone through a "fading" cycle. The usual dark, brownish clouds turn white, and after a period of time, the region returns to its normal color. Understanding this phenomenon, the latest occurring in 2010, will increase our knowledge of planetary atmospheres. Using the near infrared camera, NSFCAM2, at NASA's Infrared Telescope Facility in Hawaii, images were taken of Jupiter accompanied by data describing the circumstances of each observation. These images are then processed and reduced through an IDL program. By scanning the central meridian of the planet, graphs were produced plotting the average values across the central meridian, which are used to find variations in the region of interest. Calculations using Albert4, a FORTRAN program that calculates the upwelling reflected sunlight from a designated cloud model, can be used to determine the effects of a model atmosphere due to various absorption, scattering, and emission processes. Spectra that were produced show ammonia bands in the South Equatorial Belt. So far, we can deduce from this information that an upwelling of ammonia particles caused a cloud layer to cover up the region. Further investigations using Albert4 and other models will help us to constrain better the chemical make up of the cloud and its location in the atmosphere.

  3. ECCENTRIC JUPITERS VIA DISK–PLANET INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Duffell, Paul C.; Chiang, Eugene, E-mail: duffell@berkeley.edu, E-mail: echiang@astro.berkeley.edu [Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley (United States)

    2015-10-20

    Numerical hydrodynamics calculations are performed to determine the conditions under which giant planet eccentricities can be excited by parent gas disks. Unlike in other studies, Jupiter-mass planets are found to have their eccentricities amplified—provided their orbits start off as eccentric. We disentangle the web of co-rotation, co-orbital, and external resonances to show that this finite-amplitude instability is consistent with that predicted analytically. Ellipticities can grow until they reach of order of the disk's aspect ratio, beyond which the external Lindblad resonances that excite eccentricity are weakened by the planet's increasingly supersonic epicyclic motion. Forcing the planet to still larger eccentricities causes catastrophic eccentricity damping as the planet collides into gap walls. For standard parameters, the range of eccentricities for instability is modest; the threshold eccentricity for growth (∼0.04) is not much smaller than the final eccentricity to which orbits grow (∼0.07). If this threshold eccentricity can be lowered (perhaps by non-barotropic effects), and if the eccentricity driving documented here survives in 3D, it may robustly explain the low-to-moderate eccentricities ≲0.1 exhibited by many giant planets (including Jupiter and Saturn), especially those without planetary or stellar companions.

  4. Thermal Processes Governing Hot-Jupiter Radii

    CERN Document Server

    Spiegel, David S

    2013-01-01

    There have been many proposed explanations for the larger-than-expected radii of some transiting hot Jupiters, including either stellar or orbital energy deposition deep in the atmosphere or deep in the interior. In this paper, we explore the important influences on hot-Jupiter radius evolution of (i) additional heat sources in the high atmosphere, the deep atmosphere, and deep in the convective interior; (ii) consistent cooling of the deep interior through the planetary dayside, nightside, and poles; (iii) the degree of heat redistribution to the nightside; and (iv) the presence of an upper atmosphere absorber inferred to produce anomalously hot upper atmospheres and inversions in some close-in giant planets. In particular, we compare the radius expansion effects of atmospheric and deep-interior heating at the same power levels and derive the power required to achieve a given radius increase when night-side cooling is incorporated. We find that models that include consistent day/night cooling are more simila...

  5. The Transit Spectra of Earth and Jupiter

    CERN Document Server

    Irwin, Patrick G J; Bowles, Neil E; Fletcher, Leigh N; Aigrain, Suzanne; Lee, Jae-Min

    2014-01-01

    In recent years, a number of observations have been made of the transits of 'Hot Jupiters', such as HD 189733b, which have been modelled to derive atmospheric structure and composition. As measurement techniques improve, the transit spectra of 'Super-Earths' such as GJ 1214b are becoming better constrained, allowing model atmospheres to be fitted for this class of planet also. While it is not yet possible to constrain the atmospheric states of small planets such as the Earth or cold planets like Jupiter, this may become practical in the coming decades and if so, it is of interest to determine what we might infer from such measurements. Here we have constructed atmospheric models of the Solar System planets from 0.4 - 15.5 microns that are consistent with ground-based and satellite observations and from these calculate the primary transit and secondary eclipse spectra (with respect to the Sun and typical M-dwarfs) that would be observed by a 'remote observer', many light years away. From these spectra we test ...

  6. Tidal Response of Preliminary Jupiter Model

    Science.gov (United States)

    Wahl, Sean M.; Hubbard, William B.; Militzer, Burkhard

    2016-11-01

    In anticipation of improved observational data for Jupiter’s gravitational field, from the Juno spacecraft, we predict the static tidal response for a variety of Jupiter interior models based on ab initio computer simulations of hydrogen-helium mixtures. We calculate hydrostatic-equilibrium gravity terms, using the non-perturbative concentric Maclaurin Spheroid method that eliminates lengthy expansions used in the theory of figures. Our method captures terms arising from the coupled tidal and rotational perturbations, which we find to be important for a rapidly rotating planet like Jupiter. Our predicted static tidal Love number, {k}2=0.5900, is ˜10% larger than previous estimates. The value is, as expected, highly correlated with the zonal harmonic coefficient J 2, and is thus nearly constant when plausible changes are made to the interior structure while holding J 2 fixed at the observed value. We note that the predicted static k 2 might change, due to Jupiter’s dynamical response to the Galilean moons, and find reasons to argue that the change may be detectable—although we do not present here a theory of dynamical tides for highly oblate Jovian planets. An accurate model of Jupiter’s tidal response will be essential for interpreting Juno observations and identifying tidal signals from effects of other interior dynamics of Jupiter’s gravitational field.

  7. Terrestrial thermospheric storm effects during the first weeks of the Dynamics Explorer 1 mission

    Science.gov (United States)

    Immel, T. J.; Crowley, G.; Craven, J. D.

    2004-05-01

    Global far-ultraviolet (FUV) images of Earth provide an unparalleled view of the development of thermospheric storms during periods of enhanced magnetic activity. More than 20 years ago, the Spin Scan Imager onboard the Dynamics Explorer 1 satellite obtained the first global images of the development of thermospheric perturbations caused by enhanced auroral activity. This capability comes from the FUV component of the imager, that by measuring the bright OI 130.4-nm triplet originating in the thermosphere can monitor variations in the relative thermospheric column abundances of O and N2. Short-term variations in the ratio of these parameters usually indicate the recent occurrence of high-latitude Joule heating. The first several weeks of operation of the instrument (beginning in September, 1981) were marked by a particularly interesting series of magnetic substorm and storm events which all had an effect, to varying degrees, on the OI FUV dayglow brightness. In this study the O/N2 variations are simulated for the entire period using the NCAR TIMEGCM in order to identify the causative factors in the development of O/N2 depletions. This period was also marked by good measurements of the solar wind speed, density, and embedded magnetic field from the ISEE-3 satellite. These are important inputs for the TIMEGCM. Particular attention is paid to the sense of IMF By, which has a strong effect on the magnitude and local time of the peak in the high latitude neutral circulation speed.

  8. Zonal winds in the equatorial upper thermosphere: Decomposing the solar flux, geomagnetic activity, and seasonal dependencies

    NARCIS (Netherlands)

    Liu, H.; Lühr, H.; Watanabe, S.; Köhler, W.; Henize, V.; Visser, P.N.A.M.

    2006-01-01

    Using 3 years (2002–2004), over 16,400 orbits of measurements from the accelerometer on board the CHAMP satellite, we have studied the climatology of the equatorial zonal wind in the upper thermosphere. Several main features are noticed. The most prominent one is that the solar flux significantly in

  9. Effects of magnetospheric lobe cell convection on dayside upper thermospheric winds at high latitudes

    Science.gov (United States)

    Zhang, B.; Wang, W.; Wu, Q.; Knipp, D.; Kilcommons, L.; Brambles, O. J.; Liu, J.; Wiltberger, M.; Lyon, J. G.; Häggström, I.

    2016-08-01

    This paper investigates a possible physical mechanism of the observed dayside high-latitude upper thermospheric wind using numerical simulations from the coupled magnetosphere-ionosphere-thermosphere (CMIT) model. Results show that the CMIT model is capable of reproducing the unexpected afternoon equatorward winds in the upper thermosphere observed by the High altitude Interferometer WIND observation (HIWIND) balloon. Models that lack adequate coupling produce poleward winds. The modeling study suggests that ion drag driven by magnetospheric lobe cell convection is another possible mechanism for turning the climatologically expected dayside poleward winds to the observed equatorward direction. The simulation results are validated by HIWIND, European Incoherent Scatter, and Defense Meteorological Satellite Program. The results suggest a strong momentum coupling between high-latitude ionospheric plasma circulation and thermospheric neutral winds in the summer hemisphere during positive IMF Bz periods, through the formation of magnetospheric lobe cell convection driven by persistent positive IMF By. The CMIT simulation adds important insight into the role of dayside coupling during intervals of otherwise quiet geomagnetic activity

  10. Estimating Ionosphere-Thermosphere Energy Budget: the ICME Storm of 16-19 March 2013

    Science.gov (United States)

    Verkhoglyadova, O. P.; Meng, X.; Mannucci, A. J.; Mlynczak, M. G.; Hunt, L. A.; Lu, G.

    2016-12-01

    The ionosphere-thermosphere (IT) energy budget for the ICME storm of 16-19 March 2013 is estimated with the Global Ionosphere-Thermosphere Model (GITM), empirical models and observation-derived proxies. GITM is used to analyze the IT energy partitioning in detail, with a focus on auroral heating, Joule heating and thermospheric cooling. Solar wind data, F10.7, OVATION Prime and the Weimer 2005 model are used to drive GITM from above. Thermospheric nitric oxide and carbon dioxide cooling emission powers and fluxes are estimated from TIMED/SABER measurements. AMIE estimations of hemispheric power and Joule heating are presented, based on data from global magnetometers, the AMPERE magnetic field data, SSUSI auroral images and the SuperDARN radar network. Additionally, we inter-compare selected energy channels for five CME-type and eight HSS-type storms modeled with GITM and TIEGCM. We discuss challenges and discrepancies in estimating and modeling the IT energy budget, especially Joule heating, during geomagnetic storms.

  11. Global effect of auroral particle and Joule heating in the undisturbed thermosphere

    Science.gov (United States)

    Hinton, B. B.

    1978-01-01

    From the compositional variations observed with the neutral atmosphere composition experiment on OGO 6 and a simplified model of thermospheric dynamics, global average values of non-EUV heating are deduced. These are 0.19-0.25 mW/sq m for quiet days and 0.44-0.58 mW/sq m for ordinary days.

  12. Solar and chemical reaction-induced heating in the terrestrial mesosphere and lower thermosphere

    Science.gov (United States)

    Mlynczak, Martin G.

    1992-01-01

    Airglow and chemical processes in the terrestrial mesosphere and lower thermosphere are reviewed, and initial parameterizations of the processes applicable to multidimensional models are presented. The basic processes by which absorbed solar energy participates in middle atmosphere energetics for absorption events in which photolysis occurs are illustrated. An approach that permits the heating processes to be incorporated in numerical models is presented.

  13. Embryo impacts and gas giant mergers II: Diversity of Hot Jupiters' internal structure

    CERN Document Server

    Liu, Shang-Fei; Lin, D N C; Li, Shu-Lin

    2014-01-01

    We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas ...

  14. Safety profile of subjects treated to very low low-density lipoprotein cholesterol levels (JUPITER).

    Science.gov (United States)

    Everett, Brendan M; Mora, Samia; Glynn, Robert J; MacFadyen, Jean; Ridker, Paul M

    2014-12-01

    Recent US guidelines expand the indications for high-intensity statin therapy, yet data on the safety of attaining very low-density lipoprotein cholesterol (LDL-C) levels are scarce. Among 16,304 participants in the Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) with on-treatment LDL-C levels, we identified 767 who did and 7,387 who did not achieve LDL-C JUPITER, achieving LDL-C levels <30 mg/dl with high-intensity statin therapy appeared to be generally well tolerated but associated with certain adverse events, including more physician-reported diabetes, hematuria, hepatobiliary disorders, and insomnia. These data may guide the monitoring of patients on intensive statin therapy and adverse events in trials of therapies that lead to very low LDL-C levels.

  15. Where does the Thermospheric Ionospheric GEospheric Research (TIGER) Program go?

    Science.gov (United States)

    Schmidtke, G.; Avakyan, S. V.; Berdermann, J.; Bothmer, V.; Cessateur, G.; Ciraolo, L.; Didkovsky, L.; Dudok de Wit, T.; Eparvier, F. G.; Gottwald, A.; Haberreiter, M.; Hammer, R.; Jacobi, Ch.; Jakowski, N.; Kretzschmar, M.; Lilensten, J.; Pfeifer, M.; Radicella, S. M.; Schäfer, R.; Schmidt, W.; Solomon, S. C.; Thuillier, G.; Tobiska, W. K.; Wieman, S.; Woods, T. N.

    2015-10-01

    At the 10th Thermospheric Ionospheric GEospheric Research (TIGER/COSPAR) symposium held in Moscow in 2014 the achievements from the start of TIGER in 1998 were summarized. During that period, great progress was made in measuring, understanding, and modeling the highly variable UV-Soft X-ray (XUV) solar spectral irradiance (SSI), and its effects on the upper atmosphere. However, after more than 50 years of work the radiometric accuracy of SSI observation is still an issue and requires further improvement. Based on the extreme ultraviolet (EUV) data from the SOLAR/SolACES, and SDO/EVE instruments, we present a combined data set for the spectral range from 16.5 to 105.5 nm covering a period of 3.5 years from 2011 through mid of 2014. This data set is used in ionospheric modeling of the global Total Electron Content (TEC), and in validating EUV SSI modeling. For further investigations the period of 3.5 years is being extended to about 12 years by including data from SOHO/SEM and TIMED/SEE instruments. Similarly, UV data are used in modeling activities. After summarizing the results, concepts are proposed for future real-time SSI measurements with in-flight calibration as experienced with the ISS SOLAR payload, for the development of a space weather camera for observing and investigating space weather phenomena in real-time, and for providing data sets for SSI and climate modeling. Other planned topics are the investigation of the relationship between solar EUV/UV and visible/near-infrared emissions, the impact of X-rays on the upper atmosphere, the development of solar EUV/UV indices for different applications, and establishing a shared TIGER data system for EUV/UV SSI data distribution and real-time streaming, also taking into account the achievements of the FP7 SOLID (First European SOLar Irradiance Data Exploitation) project. For further progress it is imperative that coordinating activities in this special field of solar-terrestrial relations and solar physics is

  16. Comparison of high-latitude thermospheric meridionalwinds I: optical and radar experimental comparisons

    Directory of Open Access Journals (Sweden)

    E. M. Griffin

    2004-03-01

    Full Text Available Thermospheric neutral winds at Kiruna, Sweden (67.4°N, 20.4°E are compared using both direct optical Fabry-Perot Interferometer (FPI measurements and those derived from European incoherent scatter radar (EISCAT measurements. This combination of experimental data sets, both covering well over a solar cycle of data, allows for a unique comparison of the thermospheric meridional component of the neutral wind as observed by different experimental techniques. Uniquely in this study the EISCAT measurements are used to provide winds for comparison using two separate techniques: the most popular method based on the work of Salah and Holt (1974 and the Meridional Wind Model (MWM (Miller et al., 1997 application of servo theory. The balance of forces at this location that produces the observed diurnal pattern are investigated using output from the Coupled Thermosphere and Ionosphere (CTIM numerical model. Along with detailed comparisons from short periods the climatological behaviour of the winds have been investigated for seasonal and solar cycle dependence using the experimental techniques. While there are features which are consistent between the 3 techniques, such as the evidence of the equinoctial asymmetry, there are also significant differences between the techniques both in terms of trends and absolute values. It is clear from this and previous studies that the high-latitude representation of the thermospheric neutral winds from the empirical Horizontal Wind Model (HWM, though improved from earlier versions, lacks accuracy in many conditions. The relative merits of each technique are discussed and while none of the techniques provides the perfect data set to address model performance at high-latitude, one or more needs to be included in future HWM reformulations.

    Key words. Meteorology and atmospheric dynamics (thermospheric dynamics, Ionosphere (ionosphere-atmosphere interactions, auroral ionosphere

  17. Nature of the Venus thermosphere derived from satellite drag measurements (solicited paper)

    Science.gov (United States)

    Keating, G.; Theriot, M.; Bougher, S.

    2008-09-01

    From drag measurements obtained by Pioneer Venus and Magellan, the Venus upper atmosphere was discovered to be much colder than Earth's, even though Venus is much closer to the Sun than the Earth. On the dayside, exospheric temperatures are near 300K compared to Earth's of near 1200K [1]. This is thought to result principally from 15 micron excitation of carbon dioxide by atomic oxygen resulting in very strong 15 micron emission to space, cooling off the upper atmosphere [2]. On the nightside the Venus upper atmosphere is near 100K [3], compared to Earth where temperatures are near 900K. The nightside Venus temperatures drop with altitude contrary to a thermosphere where temperatures rise with altitude. As a result, the very cold nightside is called a "cryosphere" rather than a thermosphere. This is the first cryosphere discovered in the solar system [1]. Temperatures sharply drop near the terminator. Apparently, heat is somehow blocked near the terminator from being significantly transported to the nightside [4]. Recently, drag studies were performed on a number of Earth satellites to establish whether the rise of carbon dioxide on Earth was cooling the Earth's thermosphere similar to the dayside of Venus. Keating et al. [5] discovered that a 10 percent drop in density near 350km at solar minimum occurred globally over a period of 20 years with a 10 per cent rise in carbon dioxide. This should result in about a factor of 2 decline in density from 1976 values, by the end of the 21st century brought on by thermospheric cooling. Subsequent studies have confirmed these results. Thus we are beginning to see the cooling of Earth's upper atmosphere apparently from the same process cooling the Venus thermosphere. Fig. 1 VIRA Exospheric Temperatures Atmospheric drag data from the Pioneer Venus Orbiter and Magellan were combined to generate an improved version of the Venus International Reference Atmosphere (VIRA) [6], [7]. A "fountain effect" was discovered where the

  18. Fabry-Perot Observations of a Secondary Peak at 20-21 Local Time in the Nocturnal Thermospheric Temperature Variation at Arequipa, Peru (16.5S, 71.5 W)

    Science.gov (United States)

    Meriwether, J. W.; Faivre, M.; Akmaev, R.; Fuller-Rowell, T.; Wu, F.

    2009-05-01

    Fabry-Perot observations of the nighttime thermospheric temperature variation in the equatorial region at Arequipa, Peru (16.5 S, 71.5 W) have generally reported the detection of a midnight temperature maximum (MTM). Examination of Arequipa temperature observations for the period of 1997 to 2001 as compared with the NRL MSIS-00 empirical model also reveals the occasional appearance of a secondary temperature peak with an amplitude of 15 to 25 K in contrast to the MTM amplitude of typically 75 to 150 K. This feature is seen near 20-21 LT for perhaps 15 to 25% of the ~400 nights of winter and equinoctial observations between 1997 and 2001. There was no strong solar cycle phase dependence noted for these results. Detection was possible only when the Fabry-Perot observations in all directions were averaged to decrease the measurement error from a typical value of 40-50 K to 15-20 K. Modelling using the Whole Atmosphere Model demonstrates the detection of a similar peak near 20-21 LT in the nighttime thermal variation. The development of this peak occurs as the result of the thermal forcing by the tidal waves propagating upward from the lower thermosphere for which the multiple tidal harmonics interact with the diurnal variation of the thermospheric ion drag to produce the MTM and also sporadically, this secondary temperature peak.

  19. Dynamical Interactions Make Hot Jupiters in Open Star Clusters

    CERN Document Server

    Shara, Michael M; Mardling, Rosemary A

    2014-01-01

    Explaining the origin and evolution of exoplanetary "hot Jupiters" remains a significant challenge. One possible mechanism for their production is planet-planet interactions, which produces hot Jupiters from planets born far from their host stars but near their dynamical stability limits. In the much more likely case of planets born far from their dynamical stability limits, can hot Jupiters can be formed in star clusters? Our N-body simulations of planetary systems inside star clusters answer this question in the affirmative, and show that hot Jupiter formation is not a rare event. We detail three case studies of the dynamics-induced births of hot Jupiters on highly eccentric orbits that can only occur inside star clusters. The hot Jupiters' orbits bear remarkable similarities to those of some of the most extreme exoplanets known: HAT-P-32 b, HAT-P-2 b, HD 80606 b and GJ 876 d. If stellar perturbations formed these hot Jupiters then our simulations predict that these very hot, inner planets are sometimes acc...

  20. Jupiter's Decametric Radio Emission and the Radiation Belts of Its Galilean Satellites.

    Science.gov (United States)

    Burns, J A

    1968-03-01

    Many of the observed properties of Jupiter's decametric radiation may be explained by postulation that the inner Galilean satellites of Jupiter have magnetic properties that strongly distort Jupiter's magnetic field in the region of each satellite. Charged particles from Jupiter's radiation belts are trapped by these distorted fields and emit synchrotron radiation.

  1. C/O and O/H Ratios Suggest Some Hot Jupiters Originate Beyond the Snow Line

    Science.gov (United States)

    Brewer, John M.; Fischer, Debra A.; Madhusudhan, Nikku

    2017-02-01

    The elemental compositions of planet-hosting stars serve as proxies for the primordial compositions of protoplanetary disks within which the planets form. The temperature profile of the disk governs the condensation fronts of various compounds, and although these chemically distinct regions migrate and mix during the disk lifetime, they can still leave an imprint on the compositions of the forming planets. Observable atmospheric compositions of hot Jupiters, when compared against their host stars, could potentially constrain their formation and migration processes. We compared the measured planetary and stellar abundances of carbon and oxygen for 10 systems with hot Jupiters. If the planets formed by core accretion with significant planetesimal accretion and migrated through the disk, the hot Jupiter atmospheres should be substantially super-stellar in O/H and substellar in C/O. On the contrary, however, we find that currently reported abundances of hot Jupiters have generally super-stellar C/O ratios, although present uncertainties on the reported O/H and C/O ratios are too large to reach a firm conclusion. In one case, HD 209458b, however, the elevated C/O and depleted O/H of the planet compared to the host star are significant enough to suggest an origin far beyond the ice line, with predominantly gas accretion and subsequent disk-free migration. Improved measurements from the James Webb Space Telescope will enable more precise measurements for more hot Jupiters, and we predict, based on the current marginal trend, that a sizable fraction of hot Jupiters will show enrichment of C/O over and lower O/H than their hosts, similar to HD 209458b.

  2. THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF WARM AND HOT JUPITERS: EFFECTS OF ORBITAL DISTANCE, ROTATION PERIOD, AND NONSYNCHRONOUS ROTATION

    Energy Technology Data Exchange (ETDEWEB)

    Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States); Lewis, Nikole K. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Fortney, Jonathan J., E-mail: showman@lpl.arizona.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2015-03-10

    Efforts to characterize extrasolar giant planet (EGP) atmospheres have so far emphasized planets within 0.05 AU of their stars. Despite this focus, known EGPs populate a continuum of orbital separations from canonical hot Jupiter values (0.03–0.05 AU) out to 1 AU and beyond. Unlike typical hot Jupiters, these more distant EGPs will not generally be synchronously rotating. In anticipation of observations of this population, we here present three-dimensional atmospheric circulation models exploring the dynamics that emerge over a broad range of rotation rates and incident stellar fluxes appropriate for warm and hot Jupiters. We find that the circulation resides in one of two basic regimes. On typical hot Jupiters, the strong day–night heating contrast leads to a broad, fast superrotating (eastward) equatorial jet and large day–night temperature differences. At faster rotation rates and lower incident fluxes, however, the day–night heating gradient becomes less important, and baroclinic instabilities emerge as a dominant player, leading to eastward jets in the midlatitudes, minimal temperature variations in longitude, and, often, weak winds at the equator. Our most rapidly rotating and least irradiated models exhibit similarities to Jupiter and Saturn, illuminating the dynamical continuum between hot Jupiters and the weakly irradiated giant planets of our own solar system. We present infrared (IR) light curves and spectra of these models, which depend significantly on incident flux and rotation rate. This provides a way to identify the regime transition in future observations. In some cases, IR light curves can provide constraints on the rotation rate of nonsynchronously rotating planets.

  3. Thermospheric winds and temperatures above Mawson, Antarctica, observed with an all-sky imaging, Fabry-Perot spectrometer

    Directory of Open Access Journals (Sweden)

    C. Anderson

    2009-05-01

    Full Text Available A new all-sky imaging Fabry-Perot spectrometer has been installed at Mawson station (67°36' S, 62°52' E, Antarctica. This instrument is capable of recording independent spectra from many tens of locations across the sky simultaneously. Useful operation began in March 2007, with spectra recorded on a total of 186 nights. Initial analysis has focused on the large-scale daily and average behavior of winds and temperatures derived from observations of the 630.0 nm airglow line of atomic oxygen, originating from a broad layer centered around 240 km altitude, in the ionospheric F-region.

    The 1993 Horizontal Wind Model (HWM93, NRLMSISE-00 atmospheric model, and the Coupled Thermosphere/Ionosphere Plasmasphere (CTIP model were used for comparison. During the geomagnetically quiet period studied, observed winds and temperatures were generally well modelled, although temperatures were consistently higher than NRLMSISE-00 predicted, by up to 100 K. CTIP temperatures better matched our data, particularly later in the night, but predicted zonal winds which were offset from those observed by 70–180 ms−1 westward. During periods of increased activity both winds and temperatures showed much greater variability over time-scales of less than an hour. For the active night presented here, a period of 45 min saw wind speeds decrease by around 180 ms−1, and temperatures increase by approximately 100 K. Active-period winds were poorly modelled by HWM93 and CTIP, although observed median temperatures were in better agreement with NRLMSISE-00 during such periods.

    Average behavior was found to be generally consistent with previous studies of thermospheric winds above Mawson. The collected data set was representative of quiet geomagnetic and solar conditions. Geographic eastward winds in the afternoon/evening generally continued until around local midnight, when winds turned equatorward. Geographic meridional and

  4. Energetic electrons in Jupiter's dawn magnetodisc

    Science.gov (United States)

    Van Allen, J. A.

    1979-01-01

    The paper presents and analyzes absolute energy density data on electrons from the University of Iowa instrument on Pioneer 10 for one example of a plasma sheet traversal in Jupiter's dawn magnetodisk on 6-7 December 1973. The absolute integral omnidirectional intensity spectrum of electrons is based on a full and accurate reduction of the counting rate data. The main finding is that electrons of energy greater than 0.060 MeV provide only about 3% of the charged particle pressure required to explain the observed depression in the magnetic field at the center of the plasma sheet, in spite of the fact that the intensity of such electrons is well correlated with the depression of the magnetic pressure throughout the sheet.

  5. The dusty ballerina skirt of Jupiter

    Science.gov (United States)

    Horanyi, M.; Morfill, G.; Gruen, E.

    1993-12-01

    We suggest a model to explain the unexpected recurrent dust events that were observed during the Jupiter encounter by the dust detector on board the Ulysses spacecraft. This model is based dust-magnetosphere interactions. Dust particles inside the Jovian magnetosphere collect electrostatic charges and their interaction with the magnetic and electric fields can lead to energization and subsequent ejection. We discuss the dusty regions (ring/halo, `gossamer' ring) and also Io as potential sources for the Ulysses events. This model favors Io as a source. The mass and velocity range of the escaping particles are compatible with the observations, and we also suggest internal periodicities to explain the recurrent nature of the Ulysses dust events.

  6. Auroral meridian scanning photometer calibration using Jupiter

    Science.gov (United States)

    Jackel, Brian J.; Unick, Craig; Creutzberg, Fokke; Baker, Greg; Davis, Eric; Donovan, Eric F.; Connors, Martin; Wilson, Cody; Little, Jarrett; Greffen, M.; McGuffin, Neil

    2016-10-01

    Observations of astronomical sources provide information that can significantly enhance the utility of auroral data for scientific studies. This report presents results obtained by using Jupiter for field cross calibration of four multispectral auroral meridian scanning photometers during the 2011-2015 Northern Hemisphere winters. Seasonal average optical field-of-view and local orientation estimates are obtained with uncertainties of 0.01 and 0.1°, respectively. Estimates of absolute sensitivity are repeatable to roughly 5 % from one month to the next, while the relative response between different wavelength channels is stable to better than 1 %. Astronomical field calibrations and darkroom calibration differences are on the order of 10 %. Atmospheric variability is the primary source of uncertainty; this may be reduced with complementary data from co-located instruments.

  7. Radio observations of Jupiter-family comets

    CERN Document Server

    Crovisier, J; Bockelée-Morvan, D; Colom, P

    2008-01-01

    Radio observations from decimetric to submillimetric wavelengths are now a basic tool for the investigation of comets. Spectroscopic observations allow us i) to monitor the gas production rate of the comets, by directly observing the water molecule, or by observing secondary products (e.g., the OH radical) or minor species (e.g., HCN); ii) to investigate the chemical composition of comets; iii) to probe the physical conditions of cometary atmospheres: kinetic temperature and expansion velocity. Continuum observations probe large-size dust particles and (for the largest objects) cometary nuclei. Comets are classified from their orbital characteristics into two separate classes: i) nearly-isotropic, mainly long-period comets and ii) ecliptic, short-period comets, the so-called Jupiter-family comets. These two classes apparently come from two different reservoirs, respectively the Oort cloud and the trans-Neptunian scattered disc. Due to their different history and - possibly - their different origin, they may h...

  8. Rotational Properties of Jupiter Trojan 1173 Anchises

    Science.gov (United States)

    Chatelain, Joseph; Henry, Todd; French, Linda; Trilling, David

    2015-11-01

    Anchises (1173) is a large Trojan asteroid librating about Jupiter’s L5 Lagrange point. Here we examine its rotational and lightcurve properties by way of data collected over a 3.5 year observing campaign. The length of the campaign means that data were gathered for more than a quarter of Anchises' full orbital revolution which allows for accurate determinations of pole orientation and bulk shape properties for the asteroid that can then be compared to results of previous work (i.e. French 1987, Horner et al. 2012). In addition to light curves, photometric data taken during this campaign could potentially detect color differences between hemispheres as the viewing geometry changes over time. Understanding these details about a prominent member of the Jupiter Trojans may help us better understand the history of this fascinating and important group of asteroids.

  9. A Transiting Hot Jupiter Orbiting a Metal-Rich Star

    CERN Document Server

    Dunham, Edward W; Koch, David G; Batalha, Natalie M; Buchhave, Lars A; Brown, Timothy M; Caldwell, Douglas A; Cochran, William D; Endl, Michael; Fischer, Debra; Furesz, Gabor; Gautier, Thomas N; Geary, John C; Gilliland, Ronald L; Gould, Alan; Howell, Steve B; Jenkins, Jon M; Kjeldsen, Hans; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Meibom, Soren; Monet, David G; Rowe, Jason F; Sasselov, Dimitar D

    2010-01-01

    We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a star with unusually high metallicity, [Fe/H] = +0.34 +/- 0.04. The planet's mass is about 2/3 that of Jupiter, Mp = 0.67 Mj, and the radius is thirty percent larger than that of Jupiter, Rp = 1.32 Rj, resulting in a density of 0.35 g/cc, a fairly typical value for such a planet. The orbital period is P = 3.235 days. The host star is both more massive than the Sun, Mstar = 1.21 Msun, and larger than the Sun, Rstar = 1.39 Rsun.

  10. Maximum frequency of the decametric radiation from Jupiter

    Science.gov (United States)

    Barrow, C. H.; Alexander, J. K.

    1980-01-01

    The upper frequency limits of Jupiter's decametric radio emission are found to be essentially the same when observed from the earth or, with considerably higher sensitivity, from the Voyager spacecraft close to Jupiter. This suggests that the maximum frequency is a real cut-off corresponding to a maximum gyrofrequency of about 38-40 MHz at Jupiter. It no longer appears to be necessary to specify different cut-off frequencies for the Io and non-Io emission as the maximum frequencies are roughly the same in each case.

  11. Return to Europa: Overview of the Jupiter Europa Orbiter Mission

    Science.gov (United States)

    Clark, K.; Tan-Wang, G.; Boldt, J.; Greeley, R.; Jun, I.; Lock, R.; Ludwinski, J.; Pappalardo, R.; Van Houten, T.; Yan, T.

    2009-01-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO).

  12. Encouragement from Jupiter for Europe's Titan Probe

    Science.gov (United States)

    1996-04-01

    Huygens will transmit scientific information for 150 minutes, from the outer reaches of Titan's cold atmosphere and all the way down to its enigmatic surface. For comparison, the Jupiter Probe radioed scientific data for 58 minutes as it descended about 200 kilometres into the outer part of the atmosphere of the giant planet. The parachutes controlling various stages of Huygens' descent will rely upon a system for deployment designed and developed in Europe that is nevertheless similar to that used by the Jupiter Probe. The elaborate sequence of operations in Huygens worked perfectly during a dramatic drop test from a stratospheric balloon over Sweden in May 1995, which approximated as closely as possible to events on Titan. The performance of the American Probe at Jupiter renews the European engineers' confidence in their own descent control system, and also in the lithium sulphur-dioxide batteries which were chosen to power both Probes. "The systems work after long storage in space," comments Hamid Hassan, ESA's Project Manager for Huygens. "Huygens will spend seven years travelling to Saturn's vicinity aboard the Cassini Orbiter. The Jupiter Probe was a passenger in Galileo for six years before its release, so there is no reason to doubt that Huygens will work just as well." Huygens will enter the outer atmosphere of Titan at 20,000 kilometres per hour. A heat shield 2.7 metres in diameter will withstand the friction and slow the Probe to a speed at which parachutes can be deployed. The size of the parachute for the main phase of the descent is chosen to allow Huygens to reach the surface in about 2 hours. The batteries powering Huygens will last for about 21/2 hours. Prepared for surprises A different perspective on the Jupiter Probe comes from Jean-Pierre Lebreton, ESA's Project Scientist for Huygens. The results contradicted many preconceptions of the Galileo scientists, particularly about the abundance of water and the structure of cloud layers. Arguments

  13. INSIGHT (interaction of low-orbiting satellites with the surrounding ionosphere and thermosphere)

    Science.gov (United States)

    Schlicht, Anja; Reussner, Elisabeth; Lühr, Hermann; Stolle, Claudia; Xiong, Chao; Schmidt, Michael; Blossfeld, Mathis; Erdogan, Eren; Pancetta, Francesca; Flury, Jakob

    2016-04-01

    In the framework of the DFG special program "Dynamic Earth" the project INSIGHT, started in September 2015, is studying the interactions between the ionosphere and thermosphere as well as the role of the satellites and their instruments in observing the space environment. Accelerometers on low-Earth orbiters (LEOs) are flown to separate non-gravitational forces acting on the satellite from influences of gravitational effects. Amongst others these instruments provide valuable information for improving our understanding of thermospheric properties like densities and winds. An unexpected result, for example, is the clear evidence of geomagnetic field control on the neutral upper atmosphere. The charged particles of the ionosphere act as mediators between the magnetic field and the thermosphere. In the framework of INSIGHT the climatology of the thermosphere will be established and the coupling between the ionosphere and thermosphere is studied. There are indications that the accelerometers are influenced by systematic errors not identified up to now. For GRACE it is one of the discussed reasons, why this mission so far did not reach the baseline accuracy. Beutler et al. 2010 discussed the limited use of the GRACE accelerometer measurements in comparison to stochastic pulses in gravity field recovery. Analysis of the accelerometer measurements show many structures in the high frequency region which can be traced back to switching processes of electric circuits in the spacecraft, like heater and magnetic torquer switching, or so called twangs, which can be associated with discharging of non-conducting surfaces of the satellite. As all observed signals have the same time dependency a common origin is very likely, namely the coupling of time variable electric currents into the accelerometer signal. In GOCE gravity field gradients non-gravitational signatures around the magnetic poles are found indicating that even at lower frequencies problems occur. INSIGHT will identify

  14. The JUPITER lipid lowering trial and vitamin D: Is there a connection?

    Science.gov (United States)

    Ware, William R

    2010-04-01

    There is growing evidence that vitamin D deficiency significantly increases the risk of adverse cardiovascular events and that a vitamin D status representing sufficiency or optimum is protective. Unfortunately, in clinical trials that address interventions for reducing risk of adverse cardiovascular events, vitamin D status is not generally measured. Failure to do this has now assumed greater importance with the report of a study that found rosuvastatin at doses at the level used in a recent large randomized lipid lowering trial (JUPITER) had a large and significant impact on vitamin D levels as measured by the metabolite 25-hydroxyvitamin D. The statin alone appears to have increased this marker such that the participants on average went from deficient to sufficient in two months. The difference in cardiovascular risk between those deficient and sufficient in vitamin D in observational studies was similar to the risk reduction found in JUPITER. Thus it appears that this pleiotropic effect of rosuvastatin may be responsible for part of its unusual effectiveness in reducing the risk of various cardiovascular endpoints found in JUPITER and calls into question the interpretation based only on LDL cholesterol and CRP changes. In addition, vitamin D status is a cardiovascular risk factor which up until now has not been considered in adjusting study results or in multivariate analysis, and even statistical analysis using only baseline values may be inadequate.

  15. Embryo impacts and gas giant mergers - II. Diversity of hot Jupiters' internal structure

    Science.gov (United States)

    Liu, Shang-Fei; Agnor, Craig B.; Lin, D. N. C.; Li, Shu-Lin

    2015-01-01

    We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas through Roche lobe overflow. The impact of super-Earths on parabolic orbits can also enlarge gas giant planets' envelope and elevates their tidal dissipation rate over ˜100 Myr time scale. Since giant impacts occur stochastically with a range of impactor sizes and energies, their diverse outcomes may account for the dispersion in the mass-radius relationship of hot Jupiters.

  16. Dynamical Constraints on the Origin of Hot and Warm Jupiters with Close Friends

    Science.gov (United States)

    Antonini, Fabio; Hamers, Adrian S.; Lithwick, Yoram

    2016-12-01

    Gas giants orbiting their host star within the ice line are thought to have migrated to their current locations from farther out. Here we consider the origin and dynamical evolution of observed Jupiters, focusing on hot and warm Jupiters with outer friends. We show that the majority of the observed Jupiter pairs (20 out of 24) are dynamically unstable if the inner planet is placed at ≳1 au distance from the stellar host. This finding is at odds with formation theories that invoke the migration of such planets from semimajor axes ≳1 au due to secular dynamical processes (e.g., secular chaos, Lidov-Kozai [LK] oscillations) coupled with tidal dissipation. In fact, the results of N-body integrations show that the evolution of dynamically unstable systems does not lead to tidal migration but rather to planet ejections and collisions with the host star. This and other arguments lead us to suggest that most of the observed planets with a companion could not have been transported from farther out through secular migration processes. More generally, by using a combination of numerical and analytic techniques, we show that the high-e LK migration scenario can only account for less than 10% of all gas giants observed between 0.1 and 1 au. Simulations of multiplanet systems support this result. Our study indicates that rather than starting on highly eccentric orbits with orbital periods above 1 yr, these “warm” Jupiters are more likely to have reached the region where they are observed today without having experienced significant tidal dissipation.

  17. Improved orbits of Saturn and Jupiter from the Cassini and Juno missions

    Science.gov (United States)

    Folkner, William M.; Jacobson, Robert Arthur; Jones, Dayton

    2015-08-01

    Since entering orbit about Saturn in 2004, radio tracking data of the Cassini spacecraft has provided accurate measurements of its position leading to marked improvement in the Saturn ephemeris. The Cassini spacecraft orbit period has varied between 14 and 30 days as the orbit was changed to provide views of Saturn’s rings and satellites. This relatively large orbit period has required care to separate the spacecraft orbit relative to Saturn from the orbit of Saturn relative to the Sun. The resulting estimates give a series of range measurements of Saturn relative to Earth with accuracy of ~30 m. In addition to improving the Saturn ephemeris, the range measurements have been used to place stringent upper bounds on possible deviation from General Relativity suggested by the theory of Modified Newtonian Dynamics. The Very Large Baseline Array has been used to observe Cassini and determine the right ascension and declination of Saturn approximately every year since entering orbit. The combination of range and VLBA measurements over more than one-quarter of the Saturn orbit period have resulted in Saturn ephemeris accuracy comparable to that of the inner planets.The Juno spacecraft will enter orbit about Jupiter in July 2016. Juno will be the second spacecraft to orbit Jupiter, but the first to provide a time series of ranging measurements since the Galileo spacecraft high-gain antenna failure prevented range measurements from that mission. Ranging measurements to Juno, combined with VLBA observations, will cover less than one-quarter of an orbit period. But, when combined with the accurate measurements of the Ulysses spacecraft during Jupiter flyby in February 1992, the Jupiter ephemeris accuracy is expected to be close to that of Saturn and the inner planets.

  18. JUPITER PROJECT - JOINT UNIVERSAL PARAMETER IDENTIFICATION AND EVALUATION OF RELIABILITY

    Science.gov (United States)

    The JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) project builds on the technology of two widely used codes for sensitivity analysis, data assessment, calibration, and uncertainty analysis of environmental models: PEST and UCODE.

  19. How does stellar irradiation make hot Jupiters puffy?

    Science.gov (United States)

    Wei, Yu-Jie; Gu, Pin-Gao

    2017-06-01

    Hot Jupiters appear to be re-inflated as their host stars evolve and become more luminous, shedding more light on the intriguing correlation between stellar irradiation and the size of hot Jupiters. To account for the phenomenon, one of the well-known models is the thermal-tide scenario proposed by Arras and Socrates. We present a linear analysis of semi-diurnal thermal tides in a hot Jupiter. The Coriolis effect is added to our equation, which generates more wave modes than non-rotating models, such as Rossby, Yanai, and inertial waves. We attempt to investigate where and which mode contributes most of the torque that maintains the planet in an asynchronous state against gravitational tides, leading to re-inflation of a hot Jupiter.

  20. Pioneer Jupiter orbiter probe mission 1980, probe description

    Science.gov (United States)

    Defrees, R. E.

    1974-01-01

    The adaptation of the Saturn-Uranus Atmospheric Entry Probe (SUAEP) to a Jupiter entry probe is summarized. This report is extracted from a comprehensive study of Jovian missions, atmospheric model definitions and probe subsystem alternatives.

  1. Planetary geometry handbook: Jupiter positional data, 1985 - 2020, volume 4

    Science.gov (United States)

    Sergeyevsky, A. B.; Snyder, G. C.; Paulson, B. L.; Cunniff, R. A.

    1983-01-01

    Graphical data necessary for the analysis of planetary exploration missions to Jupiter are presented. Positional and geometric information spanning the time period from 1985 through 2020 is provided. The data and their usage are explained.

  2. Fitting Orbits to Jupiter's Moons with a Spreadsheet.

    Science.gov (United States)

    Bridges, Richard

    1995-01-01

    Describes how a spreadsheet is used to fit a circular orbit model to observations of Jupiter's moons made with a small telescope. Kepler's Third Law and the inverse square law of gravity are observed. (AIM)

  3. Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM

    Science.gov (United States)

    Sasaki, Sho; Fujimoto, Masaki; Yano, Hajime; Takashima, Takeshi; Kasaba, Yasumasa; Funase, Ryu; Tsuda, Yuichi; Kawaguchi, Junichiro; Kawakatsu, Yasuhiro; Mori, Osamu; Morimoto, Mutsuko; Yoshida, Fumi; Takato, Naruhisa

    The international mission to explore the Jovian system is planned as Europa Jupiter System Mission (EJSM) aiming at the launch in 2020. EJSM consists of (1) the Jupiter Europa Orbiter (JEO) by NASA, (2) the Jupiter Ganymede Orbiter (JGO) by ESA, and (3) the Jupiter Magnetospheric Orbiter (JMO) studied by JAXA (Japan Aerospace Exploration Agency). In February 2009, NASA and ESA decided to continue the study of EJSM as a candidate of the outer solar system mission. In JAXA, a mission plan combining Trojan asteroid explorer with JMO started. According to the mission plan, as the main spacecraft flies by Jupiter, it will deploy the JMO satellite around Jupiter. Then the main will target one (or two) Trojan asteroids. JMO is a spin-stabilized satellite which will have magnetometers, low-energy plasma spectrome-ters, medium energy particle detectors, energetic particle detectors, electric field / plasma wave instruments, an ENA imager, an EUV spectrometer, and a dust detector. Collaborating with plasma instruments on board JEO and JGO, JMO will investigate the fast-rotating huge mag-netosphere to clarify the energy procurement from the rotation of Jupiter to the magnetosphere and to clarify the interaction between the solar wind and the magnetosphere. JAXA started the study of a solar power sail for deep space explorations. In addition to the function of a solar sail (photon propulsion), the solar power sail system has very efficient ion engines where electric power is produced solar panels within the sail. Currently we are studying a mission to Jupiter and Trojan asteroids using a large (100m-scale) solar power sail that can transfer large payload as far as Jupiter. Trojan asteroids, which orbit around Jupiter's Lagrangian points, are primitive bodies with information of the early solar system as well as raw solid materials of Jovian system. Proposed instruments for the Trojan spacecraft are cameras, IR spectrometers, XRS, a laser altimeter, and a small surface rover

  4. Detection of (C-13)-ethane in Jupiter's atmosphere

    Science.gov (United States)

    Wiedemann, Guenter; Bjoraker, Gordon L.; Jennings, Donald E.

    1991-01-01

    High-resolution (C-12)- and (C-13)-ethane spectra of Jupiter were acquired with the Kitt Peak 4 m Fourier spectrometer and the Goddard postdisperser in June 1987. A relative abundance ratio (C-12/C-13) of 94 +/- 12 was derived from the measurements. This nearly terrestrial value indicates little or no fractionation of carbon isotopes when ethane is produced in the photolysis of methane in Jupiter's atmosphere.

  5. A Look Inside the Juno Mission to Jupiter

    Science.gov (United States)

    Grammier, Richard S.

    2008-01-01

    Juno, the second mission within the New Frontiers Program, is a Jupiter polar orbiter mission designed to return high-priority science data that spans across multiple divisions within NASA's Science Mission Directorate. Juno's science objectives, coupled with the natural constraints of a cost-capped, PI-led mission and the harsh environment of Jupiter, have led to a very unique mission and spacecraft design.

  6. The Jupiter Electron Scattering Program at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Arie Bodek

    2004-08-01

    JUPITER (Jlab Unified Program to Investigate nuclear Targets and Electroproduction of Resonances) is a new collaboration between the Nuclear Physics Electron Scattering and High Energy Physics Neutrino Scattering Communities to Investigate the Structure of Nucleons and Nuclei with Electron and Neutrino Beams. The first phase of JUPITER is Hall C experiment E04-001 on Inclusive Electron Scattering from Nuclear Targets. First data run of E04-001 is currently scheduled for January of 2005.

  7. An analysis of Jupiter data from the RAE-1 satellite

    Science.gov (United States)

    Carr, T. D.

    1974-01-01

    The analysis of Radio Astronomy Explorer Satellite data are presented. Radio bursts from Jupiter are reported in the frequency range 4700 KHz to 45 KHz. Strong correlations with lo were found at 4700, 3930, and 2200 KHz, while an equally strong Europa effect was observed at 1300, 900, and 700 KHz. Histograms indicating the relative probability and the successful identification of Jupiter activity were plotted, using automatic computer and visual search techniques.

  8. First Earth-Based Detection of a Superbolide on Jupiter

    Science.gov (United States)

    Hueso, R.; Wesley, A.; Go, C.; Perez-Hoyos, S.; Wong, M. H.; Fletcher, L. N.; Sanchez-Lavega, A.; Boslough, M. B.; DePater, I.; Orton, G. S.; Simon-Miller, A. A.; Djorgovski, S. G.; Edwards, M. L.; Hammel, H. B.; Clarke, J. T.; Noll, K. S.; Yanamandra-Fisher, P. A.

    2010-01-01

    Cosmic collisions can planets cause detectable optical flashes that range from terrestrial shooting stars to bright fireballs. On 2010 June 3 a bolide in Jupiter's atmosphere was simultaneously observed from the Earth by two amateur astronomers observing Jupiter in red and blue wavelengths, The bolide appeared as a flash of 2 s duration in video recording data of the planet. The analysis of the light carve of the observations results in an estimated energy of the impact of (0.9-4,0) x 10(exp 15) J which corresponds to a colliding body of 8-13 m diameter assuming a mean density of 2 g/cu cm. Images acquired a few days later by the Hubble Space Telescope and other large ground-based facilities did not show any signature of aerosol debris, temperature, or chemical composition anomaly, confirming that the body was small and destroyed in Jupiter's upper atmosphere. Several collisions of this size may happen on Jupiter on a yearly basis. A systematic study of the impact rate and size of these bolides can enable an empirical determination. of the flux of meteoroids in Jupiter with implications for the populations of small bodies in the outer solar system and may allow a better quantification of the threat of impacting bodies to Earth. The serendipitous recording of this optical flash opens a new window in the observation of Jupiter with small telescopes.

  9. Colors and Properties of Jupiter's Greeks and Trojans

    Science.gov (United States)

    Chatelain, Joseph; Henry, Todd J.; French, Linda M.; Trilling, David E.

    2016-10-01

    In this Ph.D. talk, I will present the colors and properties of Jupiter Trojan asteroids examined in my dissertation research. The Jupiter Trojan asteroids are minor bodies that orbit 60 degrees in front and 60 degrees behind Jupiter. Because these orbits are stable over the lifetime of the Solar System, the properties of these objects may inform us about the conditions under which the Solar System formed. We present BVRKCIKC photometry for over 100 of the intrinsically brightest and presumably largest members of the L4 and L5 Jupiter Trojans. We use a new principal color component derived by Chatelain et al. 2016 that is indicative of taxonomic types relevant to the Jupiter Trojan asteroids. We previously found that 76% of the largest L5 Jupiter Trojans are consistent with a D-type classification, while 24% show shallower slopes more consistent with X-type and C-type classifications. Here we extend this study to the L4 cloud and compare the two populations, as well as include findings about specific objects that have resulted from these data. Specifically, multiple photometric observations hint at color variation in some objects, and our richest datasets allow for the determination of phase curves and shapes for a handful of the most compelling asteroids including a new shape model and pole solution for 1173 Anchises. Our goal is to use this study to shed light on these fascinating objects and to place the Trojans in context in the larger Solar System.

  10. Warm Jupiters from secular planet-planet interactions

    CERN Document Server

    Petrovich, Cristobal

    2016-01-01

    Most warm Jupiters (gas-giant planets with $0.1~{\\rm AU}\\lesssim a \\lesssim1$ AU) have pericenter distances that are too large for significant orbital migration by tidal friction. We study the possibility that the warm Jupiters are undergoing secular eccentricity oscillations excited by an outer companion (a planet or star) in an eccentric and/or mutually inclined orbit. In this model the warm Jupiters migrate periodically, in the high-eccentricity phase of the oscillation when the pericenter distance is small, but are typically observed at much lower eccentricities. We show that the steady-state eccentricity distribution of the warm Jupiters migrating by this mechanism is approximately flat, which is consistent with the observed distribution if and only if we restrict the sample to warm Jupiters that have outer companions detected by radial-velocity surveys. The eccentricity distribution of warm Jupiters without companions exhibits a peak at low eccentricities ($e\\lesssim 0.2$) that must be explained by a di...

  11. Strong tidal dissipation in Io and Jupiter from astrometric observations.

    Science.gov (United States)

    Lainey, Valéry; Arlot, Jean-Eudes; Karatekin, Ozgür; Van Hoolst, Tim

    2009-06-18

    Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k(2)/Q = 0.015 +/- 0.003, where k(2) is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k(2)/Q = (1.102 +/- 0.203) x 10(-5)) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

  12. Shoemaker-Levy 9/JUPITER Collision Update

    Science.gov (United States)

    1994-05-01

    There are many signs that the upcoming collision between comet Shoemaker-Levy 9 and giant planet Jupiter is beginning to catch the imagination of the public. Numerous reports in the various media describe the effects expected during this unique event which according to the latest calculations will start in the evening of July 16 and end in the morning of July 22, 1994. (The times in this Press Release are given in Central European Summer Time (CEST), i.e., Universal Time (UT) + 2 hours. The corresponding local time in Chile is CEST - 6 hours.) Astronomers all over the world are now preparing to observe the associated phenomena with virtually all major telescopes. There will be no less than 12 different investigations at the ESO La Silla observatory during this period. This Press Release updates the information published in ESO PR 02/94 (27 January 1994) and provides details about the special services which will be provided by ESO to the media around this rare astronomical event. SCIENTIFIC EXPECTATIONS The nucleus of comet Shoemaker-Levy 9 broke into many smaller pieces during a near passage of Jupiter in July 1992. They are now moving in parallel orbits around this planet and recent calculations show with close to 100 % certainty that they will all collide with it, just two months from now. At some time, more than 20 individual nuclei were observed. This Press Release is accompanied by a photo that shows this formation, the famous "string of pearls", as it looked like in early May 1994. Both Jupiter and these nuclei have been extensively observed during the past months. A large, coordinated observing programme at La Silla has been active since early April and the first results have become available. However, while we now possess more accurate information about the comet's motion and the times of impact, there is still great uncertainty about the effects which may actually be observed at the time of the impacts. This is first of all due to the fact that it has not

  13. Temperature Swings in a Hot Jupiter's Atmosphere

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Weather variations in the atmosphere of a planet on a highly eccentric orbit are naturally expected to be extreme. Now, a study has directly measured the wild changes in the atmosphere of a highly eccentric hot Jupiter as it passes close to its host star.Diagram of the HD 80606 system. The inset images labeled AH show the temperature distribution of the planet at different stages as it swings around its star. [de Wit et al. 2016]Eccentric OpportunityFor a hot Jupiter a gas giant that orbits close to its host star the exoplanet HD 80606 b exhibits a fairly unusual path. Rather than having a circularized orbit, HD 80606 b travels on an extremely elliptic 111-day orbit, with an eccentricity of e ~ 0.93. Since the amount of flux HD 80606 b receives from its host varies by a factor of ~850 over the course of its orbit, it stands to reason that this planet must have extreme weather swings!Now a team of scientists led by Julien de Wit (Massachusetts Institute of Technology) has reanalyzed old observations of HD 80606 and obtained new ones using the Spitzer Space Telescope. The longer observing time and new data analysis techniques allowed the team to gain new insights into how the exoplanets atmosphere responds to changes in the stellar flux it receives during its orbit.Extreme VariationsBy measuring the infrared light coming from HD 80606, de Wit and collaborators modeled the planets temperature during 80 hours of its closest approach to its host star. This period of time included the ~20 hours in which most of the planets temperature change is expected to occur, as it approaches to a distance a mere 6 stellar radii from its host.The authors find that the layer of the atmosphere probed by Spitzer heats rapidly from 500K to 1400K (thats ~440F to a scalding 2000+F!) as the planet approaches periastron.The atmosphere then cools similarly quickly as the planet heads away from the star once more.Relative infrared brightness of HD 80606 b at 4.5 and 8 m. The dip marks where

  14. Formation of Jupiter using opacities based on detailed grain physics

    CERN Document Server

    Movshovitz, Naor; Podolak, Morris; Lissauer, Jack J

    2010-01-01

    Numerical simulations, based on the core-nucleated accretion model, are presented for the formation of Jupiter at 5.2 AU in 3 primordial disks with three different assumed values of the surface density of solid particles. The grain opacities in the envelope of the protoplanet are computed using a detailed model that includes settling and coagulation of grains and that incorporates a recalculation of the grain size distribution at each point in time and space. We generally find lower opacities than the 2% of interstellar values used in previous calculations [Hubickyj, O., Bodenheimer, P., Lissauer, J. J., 2005. Icarus 179, 415--431; Lissauer, J. J., Hubickyj, O., D'Angelo, G., Bodenheimer, P., 2009. Icarus 199, 338-350]. These lower opacities result in more rapid heat loss from and more rapid contraction of the protoplanetary envelope. For a given surface density of solids, the new calculations result in a substantial speedup in formation time as compared with those previous calculations. Formation times are c...

  15. Hot Jupiter Breezes: Time-dependent Outflows from Extrasolar Planets

    CERN Document Server

    Owen, James E

    2015-01-01

    We explore the dynamics of magnetically controlled outflows from Hot Jupiters, where these flows are driven by UV heating from the central star. In these systems, some of the open field lines do not allow the flow to pass smoothly through the sonic point, so that steady-state solutions do not exist in general. This paper focuses on this type of magnetic field configuration, where the resulting flow becomes manifestly time-dependent. We consider the case of both steady heating and time-variable heating, and find the time scales for the corresponding time variations of the outflow. Because the flow cannot pass through the sonic transition, it remains subsonic and leads to so-called breeze solutions. One manifestation of the time variability is that the flow samples a collection of different breeze solutions over time, and the mass outflow rate varies in quasi-periodic fashion. Because the flow is subsonic, information can propagate inward from the outer boundary, which determines, in part, the time scale of the...

  16. Transmission Spectra of Three-Dimensional Hot Jupiter Model Atmospheres

    CERN Document Server

    Fortney, J J; Showman, A P; Lian, Y; Freedman, R S; Marley, M S; Lewis, N K

    2009-01-01

    We compute models of the transmission spectra of planets HD 209458b, HD 189733b, and generic hot Jupiters. We examine the effects of temperature, surface gravity, and metallicity for the generic planets as a guide to understanding transmission spectra in general. We find that carbon dioxide absorption at 4.4 and 15 microns is prominent at high metallicity, and is a clear metallicity indicator. For HD 209458b and HD 189733b, we compute spectra for both one-dimensional and three-dimensional model atmospheres and examine the differences between them. The differences are usually small, but can be large if atmospheric temperatures are near important chemical abundance boundaries. The calculations for the 3D atmospheres, and their comparison with data, serve as constraints on these dynamical models that complement the secondary eclipse and light curve data sets. For HD 209458b, even if TiO and VO gases are abundant on the day side, their abundances can be considerably reduced on the cooler planetary limb. However, ...

  17. Visible spectral slope survey of Jupiter Trojans

    Science.gov (United States)

    Erasmus, Nicolas; Rivkin, Andrew S.; Sickafoose, Amanda A.

    2016-10-01

    Jupiter's Trojans are predicted by the Nice Model [1,2] to be Trans-Neptunian Objects (TNOs) that moved from 30+ AU to 5.2 AU during the early evolution period of the Solar System. This model, predicting giant planet migration and widespread transport of material throughout the Solar System, is however still lacking important constraints. Correlations between the composition, size, and orbital geometry of Jupiter's Trojans can provide additional information to test predicted migration and evolution models.Two main colour groups have been observed, roughly equivalent to the C (plus low-albedo X) and D classes with distinguishable spectral slopes, and one interpretation is that the two groups have different compositions [3]. Independent compositions together with hints of differing orbital inclination distributions could imply separate formation locations; therefore, determining the relative fractions of C and D asteroids at different sizes would provide a key test for Solar System dynamical models. However, there is a caveat: the distinct colour groups could also arise by other means. Regolith processes or "space weathering" such as micrometeorite impacts and UV irradiation of ice are also plausible explanations for a range of spectrographic slopes from C-like to D-like [4].Here we report on our latest survey observations at Sutherland, South Africa of approximately 50 Trojan targets using the Sutherland High Speed Optical Camera (SHOC) [5] on the 74" telescope. These observations are part of a larger multi-telescope survey to determine the spectral slopes (C-like or D-like) for multiple Trojans, focusing on those of small size. These slopes can be used to determine the relative fraction of C+X and D asteroids at different sizes to determine whether what is seen is more consistent with regolith processes or different compositions.References:[1] A. Morbidelli, et al. Nature, 435, 462-465, (2005)[2] R. Gomes, et al. Nature 435, 466-469 (2005)[3] J.P. Emery, et al. The

  18. Ionosphere-thermosphere (IT) response to solar wind forcing during magnetic storms

    Science.gov (United States)

    Huang, Cheryl Yu-Ying; Huang, Yanshi; Su, Yi-Jiun; Sutton, Eric K.; Rotan Hairston, Marc; Coley, William Robin

    2016-01-01

    During magnetic storms, there is a strong response in the ionosphere and thermosphere which occurs at polar latitudes. Energy input in the form of Poynting flux and energetic particle precipitation, and energy output in the form of heated ions and neutrals have been detected at different altitudes and all local times. We have analyzed a number of storms, using satellite data from the Defense Meteorological Satellite Program (DMSP), the Gravity Recovery and Climate Experiment (GRACE), Gravity field and steady-state Ocean Circulation Explorer (GOCE), and Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. Poynting flux measured by instruments on four DMSP spacecraft during storms which occurred in 2011-2012 was observed in both hemispheres to peak at both auroral and polar latitudes. By contrast, the measured ion temperatures at DMSP and maxima in neutral density at GOCE and GRACE altitudes maximize in the polar region most frequently with little evidence of Joule heating at auroral latitudes at these spacecraft orbital locations.

  19. Evidence of meso-scale structure in the high-latitude thermosphere

    Directory of Open Access Journals (Sweden)

    A. L. Aruliah

    Full Text Available There is a widely held assumption that the thermospheric neutral gas is slow to respond to magnetospheric forcing owing to its large inertia and therefore, may be treated as a steady state background medium for the more dynamic ionosphere. This is shown to be over simplistic. The data presented here compare direct measurements of the thermospheric neutral winds made in Northern Scandinavia by Fabry-Perot Interferometers (FPIs with direct measurements of the ionosphere made by the EISCAT radar and with model simulations. These comparisons will show that the neutral atmosphere is capable of responding to ionospheric changes on mesoscale levels, i.e., spatial and temporal scale sizes of less than a few hundred kilometres and tens of minutes, respectively.

    Key words. Atmospheric composition and structure (air-glow and aurora; instruments and techniques – Ionosphere (ionosphere-atmosphere interactions

  20. Community-wide model validation studies for systematic assessment of ionosphere-thermosphere models

    Science.gov (United States)

    Shim, Ja Soon; Kuznetsova, Maria; Rastätter, Lutz

    2016-07-01

    As an unbiased agent, the Community Coordinated Modeling Center (CCMC) has been leading community-wide model validation efforts; GEM, CEDAR and GEM-CEDAR Modeling Challenges since 2009. The CEDAR ETI (Electrodynamics Thermosphere Ionosphere) Challenge focused on the ability of ionosphere-thermosphere (IT) models to reproduce basic IT system parameters, such as electron and neutral densities, NmF2, hmF2, and Total Electron Content (TEC). Model-data time series comparisons were performed for a set of selected events with different levels of geomagnetic activity (quiet, moderate, storms). The follow-on CEDAR-GEM Challenge aims to quantify geomagnetic storm impacts on the IT system. On-going studies include quantifying the storm energy input, such as increase in auroral precipitation and Joule heating, and quantifying the storm-time variations of neutral density and TEC. In this paper, we will present lessons learned from the Modeling Challenges led by the CCMC.

  1. Equatorial particle precipitation during magnetic storms and relationship to equatorial thermospheric heating

    Energy Technology Data Exchange (ETDEWEB)

    Tinsley, B.A.; Sahai, Y.; Biondi, M.A.; Meriwether J.W. Jr.

    1988-01-01

    We compare optical observations of ring current particle precipitation from a near equatorial site in Brazil with variations in the AE and Dst indices. Precipitation occurs during ring current injection when AE is large, but for AE large without ring current injection, little precipitation is seen. Comparisons are also made with 630-nm observations of thermospheric heating made simultaneously in Peru. The thermospheric temperatures have been corrected for instrumental drift and temperature enhancements of several hundred kelvins are present. It is not possible to associate clearly the heating with direct precipitation nor in the short term with transport of heat from higher latitudes. On a longer time scale it is likely that both mid-latitude ring current sources and high-latitude Joule heating sources are involved. copyright American Geophysical Union 1988

  2. Satellite Drag Validation of the Thermosphere-Ionosphere Electrodynamics General Circulation Model

    Science.gov (United States)

    2013-02-07

    0.93% argon, with trace gases including 0.038% carbon dioxide and 0.0005% helium). These gases are mixed such that the composition is relatively...constant up to about 80 km. Above 80 km atomic species result from photodissociation and chemical reactions due to solar EUV radiation. At higher

  3. Comparison of high-latitude thermospheric meridional winds I: optical and radar experimental comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, E.M.; Mueller-Wodarg, I.C.F.; Aruliah, A.; Aylward, A. [Atmospheric Physics Lab., Univ. Coll. London, London (United Kingdom)

    2004-07-01

    Thermospheric neutral winds at Kiruna, Sweden (67.4 N, 20.4 E) are compared using both direct optical fabry-perot interferometer (FPI) measurements and those derived from European incoherent scatter radar (EISCAT) measurements. This combination of experimental data sets, both covering well over a solar cycle of data, allows for a unique comparison of the thermospheric meridional component of the neutral wind as observed by different experimental techniques. Uniquely in this study the EISCAT measurements are used to provide winds for comparison using two separate techniques: the most popular method based on the work of Salah and Holt (1974) and the meridional wind model (MWM) (Miller et al., 1997) application of servo theory. The balance of forces at this location that produces the observed diurnal pattern are investigated using output from the coupled thermosphere and ionosphere (CTIM) numerical model. Along with detailed comparisons from short periods the climatological behaviour of the winds have been investigated for seasonal and solar cycle dependence using the experimental techniques. While there are features which are consistent between the 3 techniques, such as the evidence of the equinoctial asymmetry, there are also significant differences between the techniques both in terms of trends and absolute values. It is clear from this and previous studies that the high-latitude representation of the thermospheric neutral winds from the empirical horizontal wind model (HWM), though improved from earlier versions, lacks accuracy in many conditions. The relative merits of each technique are discussed and while none of the techniques provides the perfect data set to address model performance at high-latitude, one or more needs to be included in future HWM reformulations. (orig.)

  4. Comparison of high-latitude thermospheric meridionalwinds II: combined FPI, radar and model Climatologies

    Directory of Open Access Journals (Sweden)

    E. M. Griffin

    2004-03-01

    Full Text Available The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4°N, 20.4°E has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM (Hedin et al., 1988 and the numerical Coupled Thermosphere and Ionosphere Model (CTIM are compared to the measured behaviour at Kiruna, as a single site example. The empirical International Reference Ionosphere (IRI model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using Fabry-Perot Interferometers (FPI, together with 2 separate techniques applied to the European Incoherent Scatter radar (EISCAT database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes.

    Key words. Meteorology and atmospheric dynamics (thermospheric dynamics

  5. Utilizing Probability Distribution Functions and Ensembles to Forecast lonospheric and Thermosphere Space Weather

    Science.gov (United States)

    2016-04-26

    created using probability distribution functions. This new model performs as well or better than other modern models of the solar wind velocity. In... Physics , 120: 7987-8001, doi: 10.1002/2014JA020962. Abstract: The temporal and spatial variations of the thermospheric mass density during a series of...2015), Theoretical study of zonal differences of electron density at midlatitudes with GITM simulation, J. Geophys. Res. Space Physics , 120, 2951

  6. The Change in Jupiter's Moment of Inertia due to Core Erosion and Planetary Contraction

    CERN Document Server

    Helled, Ravit

    2012-01-01

    We explore the change in Jupiter's normalized axial moment of inertia (NMOI) assuming that Jupiter undergoes core erosion. It is found that Jupiter's contraction combined with an erosion of 20 M_Earth from a primordial core of 30 M_Earth can change Jupiter's NMOI over time significantly. It is shown that Jupiter's NMOI could have changed from ~0.235 to ~0.264 throughout its evolution. We find that a NMOI value of ~0.235 as suggested by dynamical models (Ward & Canup, 2006, ApJ, 640, L91) could, in principle, be consistent with Jupiter's primordial internal structure. Low NMOI values, however, persist only for the first ~ 10^6 years of Jupiter's evolution. Re-evaluation of dynamical stability models as well as more sophisticated evolution models of Jupiter with core erosion seem to be required in order to provide more robust estimates for Jupiter's primordial NMOI.

  7. Exploration of the Jovian System by EJSM (Europa Jupiter System Mission): Origin of Jupiter and Evolution of Satellites

    Science.gov (United States)

    Sasaki, Sho; Fujimoto, Masaki; Takashima, Takeshi; Yano, Hajime; Kasaba, Yasumasa; Takahashi, Yukihiro; Kimura, Jun; Okada, Tatsuaki; Kawakatsu, Yasuhiro; Tsuda, Yuichi; Kawaguchi, Jun-Ichiro; Funase, Ryu; Mori, Osamu; Morimoto, Mutsuko; Ikoma, Masahiro; Naganuma, Takeshi; Yamaji, Atsushi; Hussmann, Hauke; Kurita, Kei; Working Group, Jupiter

    EJSM (Europa Jupiter System Mission) is a planned Jovian system mission with three spacecraft aiming at coordinated observations of the Jovian satellites especially Europa and the magnetosphere, atmosphere and interior of Jupiter. It was formerly called "Laplace" mission. In October 2007, it was selected as one of future ESA scientific missions Cosmic Vision (2015-2025). From the beginning, Japanese group is participating in the discussion process of the mission. JAXA will take a role on the magnetosphere spinner JMO (Jupiter Magnetosphere Orbiter). On the other hand, ESA will take charge of JGO (Jupiter Ganymede Orbiter) and NASA will be responsible for JEO (Jupiter Europa Orbiter). In February 2009, EJSM is prioritized as the first candidate of outer planet flagship mission and mission study continues in the course of Cosmic Vision. The expected launch time of EJSM will be expected in 2020. Currently we are seeking a possibility to combine JMO with a proposed solar sail mission of JAXA for Jupiter and one of Trojan asteroids.

  8. Comet Shoemaker-Levy 9, Jupiter, and Impact Shock Chemistry

    Science.gov (United States)

    Zahnle, Kevin; Cuzzi, Jeffrey (Technical Monitor)

    1996-01-01

    Four years ago this month, a hitherto unknown comet in loose orbit around Jupiter passed so near the giant planet that it was torn apart into 20 fragments by tides. One orbit later, two years ago this month, the fragments of doomed comet P/Shoemaker Levy (SL9) fell into Jupiter. The enormous energies of these impacts (the largest fragments were nearly 1 km across and, hitting at 60 km/s, released some 2-4 x 10(exp 27) ergs) produced enormous explosions. Several of the ejecta plumes were imaged towering 3000 km above Jupiter's limb. The heat released when the plumes fell was considerable and easily observed on Earth. The impacts produced strong shocks, both promptly at the impact site and again, later, and over thousands of kilometers, when the ejecta plume reentered the atmosphere. The focus of this talk will be to discuss what the SL9 impacts taught us about impact shock chemistry - the processes, the ingredients, the results - and what inferences we may draw for impacts on early Earth. Shock chemistry generates a suite of molecules not usually seen on Jupiter. The most surprising report was of a huge amount of diatomic sulfur S2 at the site of the G impact. Other unusual products include CS, CS2, OCS, H2S, SO2, HCN, CO, and H2O; although H2S and H2O are doubtless abundant below the visible clouds. Hot or enhanced CH4 and NH3 were also detected. A general rule of shock chemistry is that CO forms until either C or O is exhausted. If O greater than C, the other products are oxidized, and excess O goes to H2O. If C greater than O, the other products are reduced, and excess C goes to HCN, C2H2, and a wide variety of more complicated organics. Ultimately, given time, the carbon would react all the way to graphite, but in practice the reactions are incomplete. The dark ejecta debris were probably composed in part of carbonaceous particles generated by the shocks. In a sense, the SL9 impacts performed the famous Miller-Urey experiment on a grand scale, with one result

  9. FPI observations of nighttime mesospheric and thermospheric winds in China and their comparisons with HWM07

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, W.; Xu, J.; Jiang, G.; Ma, R. [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Space Weather; Liu, X. [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Space Weather; Henan Normal Univ., Xinxiang (China). College of Mathematics and Information Science; Zhou, Q. [Zhengzhou Univ. (China). School of Electrical Engineering; Miami Univ., Oxford, OH (United States). Electrical and Computer Engineering Dept.

    2013-10-01

    We analyzed the nighttime horizontal neutral winds in the middle atmosphere ({proportional_to} 87 and {proportional_to} 98 km) and thermosphere ({proportional_to} 250 km) derived from a Fabry-Perot interferometer (FPI), which was installed at Xinglong station (40.2 N, 117.4 E) in central China. The wind data covered the period from April 2010 to July 2012. We studied the annual, semiannual and terannual variations of the midnight winds at {proportional_to} 87 km, {proportional_to} 98 km and {proportional_to} 250 km for the first time and compared them with Horizontal Wind Model 2007 (HWM07). Our results show the following: (1) at {proportional_to} 87 km, both the observed and model zonal winds have similar phases in the annual and semiannual variations. However, the HWM07 amplitudes are much larger. (2) At {proportional_to} 98 km, the model shows strong eastward wind in the summer solstice, resulting in a large annual variation, while the observed strongest component is semiannual. The observation and model midnight meridional winds agree well. Both are equatorward throughout the year and have small amplitudes in the annual and semiannual variations. (3) There are large discrepancies between the observed and HWM07 winds at {proportional_to} 250 km. This discrepancy is largely due to the strong semiannual zonal wind in the model and the phase difference in the annual variation of the meridional wind. The FPI annual variation coincides with the results from Arecibo, which has similar geomagnetic latitude as Xinglong station. In General, the consistency of FPI winds with model winds is better at {proportional_to} 87 and {proportional_to} 98 km than that at {proportional_to} 250 km. We also studied the seasonally and monthly averaged nighttime winds. The most salient features include the following: (1) the seasonally averaged zonal winds at {proportional_to} 87 and {proportional_to} 98 km typically have small variations throughout the night. (2) The model zonal and

  10. Temperature and Wind Measurements in Venus Lower Thermosphere between 2007 and 2015

    Science.gov (United States)

    Krause, Pia; Sornig, Manuela; Wischnewski, Carolin; Sonnabend, Guido; Stangier, Tobias; Herrmann, Maren; Kostiuk, Theodor; Livengood, Timothy A.; Pätzold, Martin

    2016-10-01

    The structure of Venus atmosphere and its thermal and dynamical behavior was intensely studied during the past decade by groundbased and the space mission Venus Express. A comprehensive understanding of the atmosphere, however, is still missing. Direct measurements of atmospheric parameters on various time scales and at different locations across the planet are essential for better understanding and to validate global circulation models. Line-resolved spectroscopy of infrared CO2 transitions provides a powerful tool to accomplish measurements of temperature and wind speed within the neutral atmosphere, using Doppler line-broadening and Doppler shift. Temperature is the motor to drive circulation, and wind speed is the result. Measuring both provides both the basis and an empirical test for circulation models. Non-LTE emission lines at 10 µm that originate from a pressure level of 1μbar, ~110 km altitude, probe the lower thermosphere and are measurable at high spectral resolution using the infrared heterodyne spectrometers THIS (University of Cologne), HIPWAC (NASA GSFC) and MILAHI (Tohoku University).Thermal and dynamical structures on the Venus day side are retrieved using a newly developed method that considers the influence of the spectrometer field-of-view (FoV) and the dispersion of spectral properties across the FoV. New conclusions from the ground-based observing campaigns between 2007 and 2015 will be presented based on this retrieval methodology. The spatial resolution on the planetary disk is different for each campaign, depending on the apparent diameter of the planet and the diffraction-limited FoV of the telescope. Previously, a comparison of the observing campaigns was limited due to the difference in spatial resolution. The new retrieval method enables comparing observations with different observing geometry. The observations yield a large quantity of temperature and wind measurements at different positions on the planetary disk, which supports

  11. FPI observations of nighttime mesospheric and thermospheric winds in China and their comparisons with HWM07

    Directory of Open Access Journals (Sweden)

    W. Yuan

    2013-08-01

    Full Text Available We analyzed the nighttime horizontal neutral winds in the middle atmosphere (~ 87 and ~ 98 km and thermosphere (~ 250 km derived from a Fabry–Perot interferometer (FPI, which was installed at Xinglong station (40.2° N, 117.4° E in central China. The wind data covered the period from April 2010 to July 2012. We studied the annual, semiannual and terannual variations of the midnight winds at ~ 87 km, ~ 98 km and ~ 250 km for the first time and compared them with Horizontal Wind Model 2007 (HWM07. Our results show the following: (1 at ~ 87 km, both the observed and model zonal winds have similar phases in the annual and semiannual variations. However, the HWM07 amplitudes are much larger. (2 At ~ 98 km, the model shows strong eastward wind in the summer solstice, resulting in a large annual variation, while the observed strongest component is semiannual. The observation and model midnight meridional winds agree well. Both are equatorward throughout the year and have small amplitudes in the annual and semiannual variations. (3 There are large discrepancies between the observed and HWM07 winds at ~ 250 km. This discrepancy is largely due to the strong semiannual zonal wind in the model and the phase difference in the annual variation of the meridional wind. The FPI annual variation coincides with the results from Arecibo, which has similar geomagnetic latitude as Xinglong station. In General, the consistency of FPI winds with model winds is better at ~ 87 and ~ 98 km than that at ~ 250 km. We also studied the seasonally and monthly averaged nighttime winds. The most salient features include the following: (1 the seasonally averaged zonal winds at ~ 87 and ~ 98 km typically have small variations throughout the night. (2 The model zonal and meridional nighttime wind variations are typically much larger than those of observations at ~ 87 km and ~ 98 km. (3 At ~ 250 km, model zonal wind compares well with the observation in the winter. For spring and

  12. Superposed epoch analysis of storm time response of the ionosphere-thermosphere (IT) system

    Science.gov (United States)

    Oliveira, D. M.; Zesta, E.; Connor, H.; Su, Y. J.; Sutton, E. K.; Huang, C. Y.; Ober, D. M.; Delay, S. H.; Schuck, P. W.

    2015-12-01

    The thermosphere-ionosphere system response to energy input by Joule heating via Poynting flux and auroral precipitation is strongly intensified during times with high geomagnetic activity or during geomagnetic storms. The most dramatic thermospheric response is the intensification and upwelling of the thermospheric mass density. The neutral mass density is not only a key parameter to understanding the solar wind - IT coupling, but also plays an important role in understanding satellite orbital drag, which in turn impacts satellite position predictions. Results of numerical simulations and satellite observations (CHAMP and GRACE) have shown that the neutral mass density is rapidly intensified (within minutes) after the initial storm shock impact and also after the onset of storm main phase. This almost immediate response is typical of CME-driven storms in which the neutral density is enhanced first in the dayside polar cap and the intensification subsequently spreads out to all magnetic local time regions and lower latitude regions. We perform a superposed epoch analysis using CHAMP and GRACE satellite data as well as DMSP data to study the spatial and temporal distribution of the measured Poynting flux and neutral density response during the main phase of storms of different intensity. We also examine the correlation characteristics between Poynting flux and neutral density response, in space and time during the storm.

  13. Thermosphere and geomagnetic response to interplanetary coronal mass ejections observed by ACE and GRACE: Statistical results

    CERN Document Server

    Krauss, S; Veronig, A M; Baur, O; Lammer, H

    2015-01-01

    For the period July 2003 to August 2010, the interplanetary coronal mass ejection (ICME) catalogue maintained by Richardson and Cane lists 106 Earth-directed events, which have been measured in-situ by plasma and field instruments onboard the ACE satellite. We present a statistical investigation of the Earth's thermospheric neutral density response by means of accelerometer measurements collected by the GRACE satellites, which are available for 104 ICMEs in the data set, and its relation to various geomagnetic indices and characteristic ICME parameters such as the impact speed, southward magnetic field strength (Bz). The majority of ICMEs causes a distinct density enhancement in the thermosphere, with up to a factor of eight compared to the pre-event level. We find high correlations between ICME Bz and thermospheric density enhancements (~0.9), while the correlation with the ICME impact speed is somewhat smaller (~0.7). The geomagnetic indices revealing the highest correlations are Dst and SYM-H (~0.9), the l...

  14. Characterizing the thermosphere of HD209458b with UV transit observations

    CERN Document Server

    Koskinen, T T; Lavvas, P; Lewis, N K

    2010-01-01

    Transmission spectroscopy at UV wavelengths is a rich and largely unexplored source of information about the upper atmospheres of extrasolar planets. So far, UV transit observations have led to the detection of atomic hydrogen, oxygen and ionized carbon in the upper atmosphere of HD209458b. The interpretation of these observations is controversial - it is not clear if the absorption arises from an escaping atmosphere interacting with the stellar radiation and stellar wind, or the thermosphere inside the Roche lobe. Here we introduce an empirical model that can be used to analyze UV transit depths of extrasolar planets and use it to interpret the transits of HD209458b in the H Ly alpha and the OI triplet emission lines. The results indicate that the mean temperature of the thermosphere is 8,000-11,000 K and that the H2/H dissociation front is located at pressures between 0.1-1 microbar, which correspond to an altitude of 1.1 Rp. The upper boundary of the model thermosphere is located at altitudes between 2.7-3...

  15. Ionosphere-Thermosphere Coupling and Energy Partitioning During Two HSS Events

    Science.gov (United States)

    Verkhoglyadova, Olga; Mannucci, Anthony; Meng, Xing; Tsurutani, Bruce; Mlynczak, Martin; Hunt, Linda; Redmon, Robert; Green, Janet

    2015-04-01

    We analyze external driving of the ionosphere-thermosphere (IT) system during two CIR-HSS events, on 29 April - 4 May 2011 and on 8-12 May 2012. By studying similar CIR-HSS events in the same phase of a solar cycle and the same season we aim to understand differences and similarities in the magnetosphere-IT coupling caused by external driving and other factors (pre-conditioning or driving from below). We focus on understanding energy and momentum transfer (with solar wind coupling functions, Joule heating, nitric oxide (NO) infrared cooling radiation and energetic particle precipitation) and corresponding energy partitioning in the IT system. We utilize observations from DMSP, POES/MEPED and TIMED/SABER. We use the Global Ionosphere-Thermosphere Model (GITM, Ridley et al., 2006) with different driving inputs to understand the IT response. We outline a physics-based approach for forecasting moderate to intense storms in the Earth's upper atmosphere caused by solar wind disturbances. Ridley, A. J., Y. Deng, and G. Toth (2006), The global ionosphere-thermosphere model, Journal of Atmospheric and Solar-Terrestrial Physics, 68(8), 839-864, doi:10.1016/j.jastp.2006.01.008.

  16. Universal time effect in the response of the thermosphere to electric field changes

    Science.gov (United States)

    Perlongo, N. J.; Ridley, A. J.

    2016-04-01

    Understanding the dynamics of the thermospheric mass density is of paramount importance for predicting drag on low-altitude satellites, particularly during geomagnetic storms. Transient enhancements in ion velocities, which frequently occur as a result of storm-driven solar wind electric field fluctuations, cause increases in neutral density and temperature. Since the Earth's quasi-dipolar magnetic field is tilted and offset from the center of the planet, it is hypothesized that hemispheric asymmetries arise, altering the thermospheric response to energy input based upon the time of day. This study used the Global Ionosphere-Thermosphere Model (GITM) to investigate this phenomenon via a series of 22 idealized simulations, where the convective electric field was enhanced for 1 h of the day. Two configurations of the Earth's magnetic field were considered, the International Geomagnetic Reference Field (IGRF) and a centered dipole. These runs were conducted at March equinox when the amount of sunlight falling on the two hemispheres was the same. Two additional sets of runs were conducted at the June and December solstices for comparison. It was found that the most geoeffective times were those times when the geomagnetic poles were pointed toward the Sun. This orientation maximizes the photoionization colocated with the high-latitude potential pattern, leading to more in Joule heating.

  17. Evidence for Solar Cycle Influence on the Infrared Energy Budget and Radiative Cooling of the Thermosphere

    Science.gov (United States)

    Mlynczak, Martin G.; Martin-Torres, F. Javier; Marshall, B. Thomas; Thompson, R. Earl; Williams, Joshua; Turpin, TImothy; Kratz, D. P.; Russell, James M.; Woods, Tom; Gordley, Larry L.

    2007-01-01

    We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 m has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period.

  18. Ionospheric Spread-F and couplings between thermosphere and lower atmosphere (Invited)

    Science.gov (United States)

    Xiao, Z.

    2010-12-01

    Ionospheric Spread-F is a widely studied subject due to its significance in understanding physical essentials of the ionospheric irregularities and applications in scintillations prediction of radio wave propagation. The occurrence of Spread-F is affected by many factors such as density gradient below the F2 peak, neutral wind, electric field and so on. All these factors are necessary as the background for Spread-F to occur while not sufficient. There seems some triggering mechanisms are needed for spread-F to onset. Among the triggering factors, acoustic gravity wave is very important in seeding Spread-F occurring. In this paper, observational evidences based on ionospheric HF Doppler measurements are provided to show that in many cases spread-F are accompanied with wave-like disturbances, especially, when the amplitudes of such disturbances are large. These kinds of wave-like disturbances are known as acoustic gravity waves. We recognized these waves are originated from severe disturbances in the lower atmosphere such as typhoon, volcano eruption and some post-earthquake effects. Although many statistics indicate that Spread-F is correlated with solar and geomagnetic activities the occurrence of it is not controlled directly by any solar events such as flares or CME. Thus, in a sense, Spread-F is a manifestation of couplings between thermosphere and lower atmosphere and it might be a hint for us to explain some regional features of thermosphere by the different conditions of lower atmosphere under thermosphere.

  19. New modes and mechanisms of thermospheric mass density variations from GRACE accelerometers

    Science.gov (United States)

    Calabia, Andres; Jin, Shuanggen

    2016-11-01

    Monitoring and understanding the upper atmosphere processes is important for orbital decay and space physics. Nowadays, Low Earth Orbit (LEO) accelerometers provide a unique opportunity to study thermospheric density variations with unprecedented details. In this paper, thermospheric mass densities variations from Gravity Recovery and Climate Experiment (GRACE) accelerometers are investigated for the period 2003-2016 using the principal component analysis (PCA). The resulting modes are analyzed and parameterized in terms of solar and magnetospheric forcing, local solar time (LST), and annual variations. A better understanding of global thermospheric air density variations is presented, which validates the suitability of our technique and model. The parameterization of the subsolar-point annual variation shows two maxima around June and only one in December. The LST parameterization shows a new fluctuation controlling a middle latitude four-wave pattern, with two maxima at 12 h and 21 h LST and two minima at 1 h and 17 h LST. Our parameterizations are suitable to represent small-scale variations including, e.g., the equatorial mass density anomaly (EMA) and the midnight density maximum (MDM). Finally, the residuals are analyzed in the spectral domain, and additional contributions are found at the frequencies of the radiational tides and at the periods of 83, 93, 152, and 431 days.

  20. Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Instrument Design and Calibration

    Science.gov (United States)

    Englert, Christoph R.; Harlander, John M.; Brown, Charles M.; Marr, Kenneth D.; Miller, Ian J.; Stump, J. Eloise; Hancock, Jed; Peterson, James Q.; Kumler, Jay; Morrow, William H.; Mooney, Thomas A.; Ellis, Scott; Mende, Stephen B.; Harris, Stewart E.; Stevens, Michael H.; Makela, Jonathan J.; Harding, Brian J.; Immel, Thomas J.

    2017-04-01

    The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument was built for launch and operation on the NASA Ionospheric Connection Explorer (ICON) mission. The instrument was designed to measure thermospheric horizontal wind velocity profiles and thermospheric temperature in altitude regions between 90 km and 300 km, during day and night. For the wind measurements it uses two perpendicular fields of view pointed at the Earth's limb, observing the Doppler shift of the atomic oxygen red and green lines at 630.0 nm and 557.7 nm wavelength. The wavelength shift is measured using field-widened, temperature compensated Doppler Asymmetric Spatial Heterodyne (DASH) spectrometers, employing low order échelle gratings operating at two different orders for the different atmospheric lines. The temperature measurement is accomplished by a multichannel photometric measurement of the spectral shape of the molecular oxygen A-band around 762 nm wavelength. For each field of view, the signals of the two oxygen lines and the A-band are detected on different regions of a single, cooled, frame transfer charge coupled device (CCD) detector. On-board calibration sources are used to periodically quantify thermal drifts, simultaneously with observing the atmosphere. The MIGHTI requirements, the resulting instrument design and the calibration are described.

  1. Survival of water ice in Jupiter Trojans

    CERN Document Server

    Guilbert-Lepoutre, Aurélie

    2014-01-01

    Jupiter Trojans appear to be a key population of small bodies to study and test the models of the Solar System formation and evolution. Because understanding the evolution of Trojans can bring strong and unique constraints on the origins of our planetary system, a significant observational effort has been undertaken to unveil their physical characteristics. The data gathered so far are consistent with Trojans having volatile-rich interiors (possibly water ice) and volatile-poor surfaces (fine grained silicates). Since water ice is not thermodynamically stable against sublimation at the surface of an object located at ~5 AU, such layering seems consistent with past outgassing. In this work, we study the thermal history of Trojans after the formation of a dust mantle by possible past outgassing, so as to constrain the depth at which water ice could be stable. We find that it could have survived 100 m below the surface, even if Trojans orbited close to the Sun for ~10,000 years, as suggested by the most recent d...

  2. The magnetic fields of Jupiter and Saturn

    Science.gov (United States)

    Ness, N. F.

    1981-01-01

    The magnetic fields of Jupiter and Saturn and the characteristics of their magnetospheres, formed by interaction with the solar wind, are discussed. The origins of both magnetic fields are associated with a dynamo process deep in the planetary interior. The Jovian magnetosphere is analogous to that of a pulsar magnetosphere: a massive central body with a rapid rotation and an associated intense magnetic field. Its most distinctive feature is its magnetodisk of concentrated plasma and particle flux, and reduced magnetic field intensity. The magnetopause near the subsolar point has been observed at radial distances ranging over 50 to 100 Jovian radii, implying a relatively compressible obstacle to solar wind flow. The composition of an embedded current sheet within the magnetic tail is believed to be influenced by volcanic eruptions and emissions from Io. Spectral troughs of the Jovian radiation belts have been interpreted as possible ring particles. The Saturnian magnetosphere appears to be more like the earth in its topology. It is mainly characterized by a dipole axis parallel to the rotational axis of the planet and a magnetic field intensity much less than expected.

  3. Hot Super Earths: disrupted young jupiters?

    CERN Document Server

    Nayakshin, Sergei

    2011-01-01

    Recent {\\em Kepler} observations revealed an unexpected abundance of "hot" Earth-size to Neptune-size planets in the inner $0.02-0.2$ AU from their parent stars. We propose that these smaller planets are the remnants of massive giant planets that migrated inward quicker than they could contract. We show that such disruptions naturally occur in the framework of the Tidal Downsizing hypothesis for planet formation. We find that the characteristic planet-star separation at which such "hot disruptions" occur is $R \\approx 0.03-0.2$ AU. This result is independent of the planet's embryo mass but is dependent on the accretion rate in the disc. At high accretion rates, $\\dot M \\simgt 10^{-6}\\msun$ yr$^{-1}$, the embryo is unable to contract quickly enough and is disrupted. At late times, when the accretion rate drops to $\\dot M \\simlt 10^{-8} \\msun$ yr$^{-1}$, the embryos migrate sufficiently slow to not be disrupted. These "late arrivals" may explain the well known population of hot jupiters. If type I migration reg...

  4. Ground based spectroscopy of hot Jupiters

    Science.gov (United States)

    Waldmann, Ingo

    2010-05-01

    It has been shown in recent years with great success that spectroscopy of exoplanetary atmospheres is feasible using space based observatories such as the HST and Spitzer. However, with the end of the Spitzer cold-phase, space based observations in the near to mid infra-red are limited, which will remain true until the the onset of the JWST. The importance of developing methods of ground based spectroscopic analysis of known hot Jupiters is therefore apparent. In the past, various groups have attempted exoplanetary spectroscopy using ground based facilities and various techniques. Here I will present results using a novel spectral retrieval method for near to mid infra-red emission and transmission spectra of exoplanetary atmospheres taken from the ground and discuss the feasibility of future ground-based spectroscopy in a broader context. My recently commenced PhD project is under the supervision of Giovanna Tinetti (University College London) and in collaboration with J. P. Beaulieu (Institut d'Astrophysique de Paris), Mark Swain and Pieter Deroo (Jet Propulsion Laboratory, Caltech).

  5. Return to Europa: Overview of the Jupiter Europa orbiter mission

    Science.gov (United States)

    Clark, K.; Boldt, J.; Greeley, R.; Hand, K.; Jun, I.; Lock, R.; Pappalardo, R.; van Houten, T.; Yan, T.

    2011-08-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter's icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the EJSM; JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO). The JEO mission concept uses a single orbiter flight system that would travel to Jupiter by means of a multiple-gravity-assist trajectory and then perform a multi-year study of Europa and the Jupiter system, including 30 months of Jupiter system science and a comprehensive Europa orbit phase of 9 months.The JEO mission would investigate various options for future surface landings. The JEO mission science objectives, as defined by the international EJSM Science Definition Team, include:Europa's ocean: Characterize the extent of the ocean and its relation to the deeper interior.Europa's ice shell: Characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange.Europa's chemistry: Determine global surface compositions and chemistry, especially as related to habitability.Europa's geology: Understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ

  6. Mean winds of the mesosphere and lower thermosphere at 52° N in the period 1988–2000

    Directory of Open Access Journals (Sweden)

    H. R. Middleton

    Full Text Available A meteor radar in the UK (near 52° N has been used to measure the mean winds of the mesosphere/lower-thermosphere (MLT region over the period 1988–2000. The seasonal course and interannual variability is characterised and comparisons are made with a number of models. Annual mean wind trends were found to be + 0.37 ms-1 yr-1 for the zonal component and + 0.157 ms-1 yr-1 for the meridional component. Seasonal means revealed significant trends in the case of meridional winds in spring ( + 0.38 ms-1 yr-1 and autumn ( + 0.29 ms-1 yr-1, and zonal winds in summer ( + 0.48 ms-1 yr-1 and autumn ( + 0.38 ms-1 yr-1. Significant correlation coefficients, R, between the sunspot number and seasonal mean wind are found in four instances. In the case of the summer zonal winds, R = + 0.732; for the winter meridional winds, R = - 0.677; for the winter zonal winds, R = - 0.472; and for the autumn zonal winds R = + 0.508.

    Key words. Meteorology and atmospheric dynamics (climatology; general circulation; middle atmospheric dynamics

  7. Jupiter's winds and Arnol'd's second stability theorem: Slowly moving waves and neutral stability

    Science.gov (United States)

    Stamp, Andrew P.; Dowling, Timothy E.

    1993-01-01

    Since the Voyager encounters in 1979, it has been known that Jupiter's cloud-top zonal winds violate the barotropic stability criterion. A vortex-tube stretching analysis of the Voyager wind data indicates that the more general Charney-Stern stability criterion is also violated. On the other hand, the zonal winds determined by tracking cloud features in Hubble Space Telescope images taken in 1991 precisely match the zonal winds determined by tracking cloud features in Voyager images, and it is hard to understand how a complicated zonal wind profile like Jupiter's could be unstable and yet not change at all in 12 years. In fact, there are at least two unknown ways to violate the Charney-Stern stability criterion and still have a stable flow. The better known of these is called Fjortoft's theorem, or Arnol'd's 1st theorem for the case of large-amplitude perturbations. Although the Fjortoft-Arnol'd theorem has been extended from the quasi-geostrophic equations to the primitive equations, the basic requirement that the potential vorticity be an increasing function of streamfunction is opposite to the case found in Jupiter, where the Voyager data indicate that the potential vorticity is a decreasing function of streamfunction. But this second case is precisely that which is covered by Arnol'd's 2nd stability theorem. In fact, the Voyager data suggest that Jupiter's zonal winds are neutrally stable with respect to Arnol'd's 2nd stability theorem. Here, we analyze the linear stability problem of a one-parameter family of sinusoidal zonal wind profiles that are close to neutral stability with respect to Arnol'd's 2nd stability theorem. We find numerically that the most unstable mode is always stationary, which may help to explain the slowly moving mode 10 waves observed on Jupiter. We find that violation of Arnol'd's 2nd stability theorem is both necessary and sufficient for instability of sinusoidal profiles. However, there appears to be no simple extension of Arnol'd's 2

  8. Hubble Views Ancient Storm in the Atmosphere of Jupiter - Montage

    Science.gov (United States)

    1999-01-01

    When 17th-century astronomers first turned their telescopes to Jupiter, they noted a conspicuous reddish spot on the giant planet. This Great Red Spot is still present in Jupiter's atmosphere, more than 300 years later. It is now known that it is a vast storm, spinning like a cyclone. Unlike a low-pressure hurricane in the Caribbean Sea, however, the Red Spot rotates in a counterclockwise direction in the southern hemisphere, showing that it is a high-pressure system. Winds inside this Jovian storm reach speeds of about 270 mph.The Red Spot is the largest known storm in the Solar System. With a diameter of 15,400 miles, it is almost twice the size of the entire Earth and one-sixth the diameter of Jupiter itself.The long lifetime of the Red Spot may be due to the fact that Jupiter is mainly a gaseous planet. It possibly has liquid layers, but lacks a solid surface, which would dissipate the storm's energy, much as happens when a hurricane makes landfall on the Earth. However, the Red Spot does change its shape, size, and color, sometimes dramatically. Such changes are demonstrated in high-resolution Wide Field and Planetary Cameras 1 & 2 images of Jupiter obtained by NASA's Hubble Space Telescope, and presented here by the Hubble Heritage Project team. The mosaic presents a series of pictures of the Red Spot obtained by Hubble between 1992 and 1999 (see PIA01594 thru PIA01599 and PIA02400 thru PIA02402 for individual images).Astronomers study weather phenomena on other planets in order to gain a greater understanding of our own Earth's climate. Lacking a solid surface, Jupiter provides us with a laboratory experiment for observing weather phenomena under very different conditions than those prevailing on Earth. This knowledge can also be applied to places in the Earth's atmosphere that are over deep oceans, making them more similar to Jupiter's deep atmosphere.

  9. Variability of the Thermosphere and Ionosphere of Mars: MAVEN NGIMS Measurements and Global Model Simulations

    Science.gov (United States)

    Bougher, Stephen; Benna, Mehdi; Jakosky, Bruce; Bell, Jared; Mahaffy, Paul; Olsen, Kirk; Roeten, Kali; Elrod, Meredith

    2016-07-01

    The Mars upper atmosphere, encompassing the thermosphere, ionosphere, and lower portion of the exosphere (~100 to 500 km), constitutes the reservoir that regulates present day escape processes from the planet. In principle, it is possible to constrain the current atmospheric escape rates making use of MAVEN measurements over this reservoir region and at higher altitudes. However, without knowledge of the physics and chemistry operating in this reservoir region and driving its significant variations (e.g., solar cycle, solar rotational, seasonal, and diurnal), it is not possible to reliably extrapolate the results over evolutionary history. The characterization of this thermosphere-ionosphere-exosphere reservoir is therefore one of the major science objectives of the MAVEN mission. Recent thermospheric-ionospheric measurements from MAVEN in-situ (NGIMS: Mahaffy et al., 2015, GRL, 42; Benna et al., 2015, GRL, 42) and remote (IUVS: Jain et al. 2015, GRL, 42) instruments indicate striking variability both spatially and temporally during the MAVEN mission thusfar. The first 16-months of MAVEN NGIMS operations (October 2014 to January 2016) is the focus of our extended study here, including both Deep Dip and Science orbits. For the thermosphere, both NGIMS neutral densities and temperatures are shown to vary significantly on diurnal, seasonal, 27-day, and partial solar cycle timescales. NGIMS neutral densities are used to derive temperature profiles, including exospheric temperatures. Solar driven (periodic) variations are certainly present in the NGIMS neutral structure. However, wave structures (i.e. gravity waves, non-migrating and migrating tides) are also clearly discernable. The extraction of solar driven features requires that at least 11-orbit averages of densities or temperatures must be conducted to remove longitude effects, and to reduce the magnitudes of gravity wave features in order that climatic trends can be identified and examined. For the ionosphere

  10. Numerical modelling of the thermospheric and ionospheric effects of magnetospheric processes in the cusp region

    Directory of Open Access Journals (Sweden)

    A. A. Namgaladze

    Full Text Available The thermospheric and ionospheric effects of the precipitating electron flux and field-aligned-current variations in the cusp have been modelled by the use of a new version of the global numerical model of the Earth's upper atmosphere developed for studies of polar phenomena. The responses of the electron concentration, ion, electron and neutral temperature, thermospheric wind velocity and electric-field potential to the variations of the precipitating 0.23-keV electron flux intensity and field-aligned current density in the cusp have been calculated by solving the corresponding continuity, momentum and heat balance equations. Features of the atmospheric gravity wave generation and propagation from the cusp region after the electron precipitation and field-aligned current-density increases have been found for the cases of the motionless and moving cusp region. The magnitudes of the disturbances are noticeably larger in the case of the moving region of the precipitation. The thermospheric disturbances are generated mainly by the thermospheric heating due to the soft electron precipitation and propagate to lower latitudes as large-scale atmospheric gravity waves with the mean horizontal velocity of about 690 m s–1. They reveal appreciable magnitudes at significant distances from the cusp region. The meridional-wind-velocity disturbance at 65° geomagnetic latitude is of the same order (100 m s–1 as the background wind due to the solar heating, but is oppositely directed. The ionospheric disturbances have appreciable magnitudes at the geomagnetic latitudes 70°–85°. The electron-concentration and -temperature disturbances are caused mainly by the ionization and heating processes due to the precipitation, whereas the ion-temperature disturbances are influence strongly by Joule heating of the ion gas due to the electric-field disturbances in the cusp. The latter strongly influence the

  11. A pseudo 2D chemical model of hot Jupiter atmospheres: application to HD 209458b and HD 189733b

    CERN Document Server

    Agundez, Marcelino; Venot, Olivia; Hersant, Franck; Selsis, Franck

    2014-01-01

    We have developed a pseudo two-dimensional model of a planetary atmosphere, which takes into account thermochemical kinetics, photochemistry, vertical mixing, and horizontal transport, the latter being modeled as a uniform zonal wind. We have applied the model to the atmospheres of the hot Jupiters HD 209458b and HD 189733b. The adopted eddy diffusion coefficients are calculated by following the behaviour of passive tracers in three-dimensional general circulation models, which results in eddy values significantly below previous estimates. We find that the distribution of molecules with altitude and longitude in the atmospheres of these two hot Jupiters is complex because of the interplay of the various physical and chemical processes at work. Much of the distribution of molecules is driven by the strong zonal wind and the limited extent of vertical transport, resulting in an important homogenisation of the chemical composition with longitude. In general, molecular abundances are quenched horizontally to valu...

  12. Imaging Jupiter Radiation Belts At Low Frequencies

    Science.gov (United States)

    Girard, J. N.; de Pater, I.; Zarka, P.; Santos-Costa, D.; Sault, R.; Hess, S.; Cecconi, B.; Fender, R.; Pewg, Lofar

    2014-04-01

    The ultra-relativistic electrons, trapped in the inner radiation belts of Jupiter, generates a strong synchrotron radio emission (historically known as the jovian decimeter radiation (DIM)) which is beamed, polarized (~20% linear, ~1% circular) and broadband. It has been extensively observed by radio telescopes/ probes and imaged by radio interferometers over a wide frequency spectrum (from >300 MHz up to 22 GHz). This extended emission presents two main emission peaks constantly located on both sides of the planet close to the magnetic plane. High latitude emissions were also regularly observed at particular frequencies, times and in particular observational configurations. This region of the magnetosphere is "frozen" due to the strong magnetic field (~4.2 G as the equator) and therefore is forced to rotate at the planetary period (T≈9h55m). Due to the tilt (~ 10o) between the spin axis of the planet and the magnetic axis (which can be seen as dipolar in first approximation), the belts and the associated radio emission wobble around the planet center. The analysis of the flux at different frequencies highlighted spatial, temporal and spectral variabilities which origins are now partly understood. The emission varies at different time scales (short-time variations of hours to long-term variation over decades) due to the combination of visibility effect (wobbling, beaming, position of the observer in the magnetic rotating reference frame) [1], [2] and intrinsic local variations (interaction between relativistic electrons and satellites/dust, delayed effect of the solar wind ram pressure, impacts events) [3], [4], [5]. A complete framework is necessary to fully understand the source, loss and transport processes of the electrons originating from outside the belt, migrating by inward diffusion and populating the inner region of the magnetosphere. Only a few and unresolved measurements were made below 300 MHz and the nonsystematic observation of this radio emission

  13. Transitions in the cloud composition of hot Jupiters

    Science.gov (United States)

    Parmentier, Vivien; Fortney, Jonathan J.; Showman, Adam; Morley, Caroline; Marley, Mark S.

    2016-10-01

    Over a large range of equilibrium temperatures, clouds shape the transmission spectrum of hot Jupiter atmospheres, yet their composition remains unknown. Recent observations show that the Kepler lightcurves of some hot Jupiters are asymmetric: for the hottest planets, the lightcurve peaks before secondary eclipse, whereas for planets cooler than 1900K, it peaks after secondary eclipse. We use the thermal structure from 3D global circulation models to determine the expected cloud distribution and Kepler lightcurves of hot Jupiters. We demonstrate that the change from an optical lightcurve dominated by thermal emission to one dominated by scattering (reflection) naturally explains the observed trend from negative to positive offset. For the cool planets the presence of an asymmetry in the Kepler lightcurve is a telltale sign of the cloud composition, because each cloud species can produce an offset only over a narrow range of effective temperatures. By comparing our models and the observations, we show that the cloud composition of hot Jupiters likely varies with equilibrium temperature. We suggest that a transition occurs between silicate and manganese sulfide clouds at a temperature near 1600K, analogous to the L/T transition on brown dwarfs. The cold trapping of cloud species below the photosphere naturally produces such a transition and predicts similar transitions for other condensates, including TiO. We predict that most hot Jupiters should have cloudy nightsides, that partial cloudiness should be common at the limb and that the dayside hot spot should often be cloud-free.

  14. XMM-Newton X-Ray Observation of Jupiter

    Science.gov (United States)

    Waite, J. Hunter

    2005-01-01

    Soft X-ray emission has been observed from the disk of both Jupiter and Saturn as well as from the auroral regions of these planets. The low-latitude disk emission as observed by ROSAT, the Chandra X-Ray Observatory, and XMM-Newton appears to be uniformly distributed across the disk and to be correlated with solar activity. These characteristics suggest that the disk x-rays are produced by: (1) the elastic scattering of solar X-rays by atmospheric neutrals and (2) the absorption of solar X-rays in the carbon K-shell followed by fluorescent emission. The carbon atoms are found in methane molecules located below the homopause. In this paper we present the results of calculations of the scattering albedo for soft x-rays. We also show the calculated x-ray intensity for a range of atmospheric abundances for Jupiter and Saturn and for a number of solar irradiance spectra. The model calculations are compared with recent x-ray observations of Jupiter and Saturn. We conclude that the emission of soft x-rays from the disks of Jupiter and Saturn can be largely explained by the scattering and fluorescence of soft x-rays. We suggest that measured x-ray intensities from the disk regions of Jupiter

  15. The mass disruption of Jupiter Family comets

    Science.gov (United States)

    Belton, Michael J. S.

    2015-01-01

    I show that the size-distribution of small scattered-disk trans-neptunian objects when derived from the observed size-distribution of Jupiter Family comets (JFCs) and other observational constraints implies that a large percentage (94-97%) of newly arrived active comets within a range of 0.2-15.4 km effective radius must physically disrupt, i.e., macroscopically disintegrate, within their median dynamical lifetime. Additional observational constraints include the numbers of dormant and active nuclei in the near-Earth object (NEO) population and the slope of their size distributions. I show that the cumulative power-law slope (-2.86 to -3.15) of the scattered-disk TNO hot population between 0.2 and 15.4 km effective radius is only weakly dependent on the size-dependence of the otherwise unknown disruption mechanism. Evidently, as JFC nuclei from the scattered disk evolve into the inner Solar System only a fraction achieve dormancy while the vast majority of small nuclei (e.g., primarily those with effective radius Morbidelli, A., Dones, L., Jedicke, R., Wiegert, P.A., Bottke Jr., W.F. [2002]. Science 296, 2212-2215) suggesting that all types of comet nuclei may have similar structural characteristics even though they may have different source regions and thermal histories. The typical disruption rate for a 1 km radius active nucleus is ∼5 × 10-5 disruptions/year and the dormancy rate is typically 3 times less. We also estimate that average fragmentation rates range from 0.01 to 0.04 events/year/comet, somewhat above the lower limit of 0.01 events/year/comet observed by Chen and Jewitt (Chen, J., Jewitt, D.C. [1994]. Icarus 108, 265-271).

  16. Electromagnetic energy deposition rate in the polar upper thermosphere derived from the EISCAT Svalbard radar and CUTLASS Finland radar observations

    Directory of Open Access Journals (Sweden)

    H. Fujiwara

    2007-11-01

    Full Text Available From simultaneous observations of the European incoherent scatter Svalbard radar (ESR and the Cooperative UK Twin Located Auroral Sounding System (CUTLASS Finland radar on 9 March 1999, we have derived the height distributions of the thermospheric heating rate at the F region height in association with electromagnetic energy inputs into the dayside polar cap/cusp region. The ESR and CUTLASS radar observations provide the ionospheric parameters with fine time-resolutions of a few minutes. Although the geomagnetic activity was rather moderate (Kp=3+~4, the electric field obtained from the ESR data sometimes shows values exceeding 40 mV/m. The estimated passive energy deposition rates are also larger than 150 W/kg in the upper thermosphere over the ESR site during the period of the enhanced electric field. In addition, enhancements of the Pedersen conductivity also contribute to heating the upper thermosphere, while there is only a small contribution for thermospheric heating from the direct particle heating due to soft particle precipitation in the dayside polar cap/cusp region. In the same period, the CUTLASS observations of the ion drift show the signature of poleward moving pulsed ionospheric flows with a recurrence rate of about 10–20 min. The estimated electromagnetic energy deposition rate shows the existence of the strong heat source in the dayside polar cap/cusp region of the upper thermosphere in association with the dayside magnetospheric phenomena of reconnections and flux transfer events.

  17. MIPAS temperature from the stratosphere to the lower thermosphere: comparison of version vM21 with ACE-FTS, MLS, OSIRIS, SABER, SOFIE and lidar measurements

    Directory of Open Access Journals (Sweden)

    M. García-Comas

    2014-07-01

    Full Text Available We present vM21 MIPAS temperatures from the lower stratosphere to the lower thermosphere, which cover all optimized resolution measurements performed by MIPAS in the Middle Atmosphere, Upper Atmosphere and NoctiLucent Cloud modes during its lifetime. i.e., from January 2005 to March 2012. The main upgrades with respect to the previous version of MIPAS temperatures (vM11 are the update of the spectroscopic database, the use of a different climatology of atomic oxygen and carbon dioxide, and the improvement of important technical aspects of the retrieval setup (temperature gradient along the line of sight and offset regularizations, apodization accuracy. Additionally, an updated version of ESA calibrated L1b spectra (5.02/5.06 is used. The vM21 temperatures correct the main systematic errors of the previous version because they on average provide a 1–2 K warmer stratopause and middle mesosphere, and a 6–10 K colder mesopause (except in high latitude summers and lower thermosphere. These lead to a remarkable improvement of MIPAS comparisons with ACE-FTS, MLS, OSIRIS, SABER, SOFIE and the two Rayleigh lidars at Mauna Loa and Table Mountain, that, with few specific exceptions, typically exhibit differences smaller than 1 K below 50 km and than 2 K at 50–80 km in spring, autumn, winter at all latitudes, and summer at low to mid-latitudes. Differences in the high latitude summers are typically smaller than 1 K below 50 km, smaller than 2 K at 50–65 km and 5 K at 65–80 km. Differences with the other instruments in the mid-mesosphere are generally negative. MIPAS mesopause is within 4 K of the other instruments measurements, except in the high latitude summers, where it is within 5–10 K of the other instruments, being warmer than SABER, MLS and OSIRIS and colder than ACE-FTS and SOFIE. The agreement in the lower thermosphere is typically better than 5 K, except for high latitudes during spring and summer, where MIPAS usually exhibits larger

  18. Hot Jupiters Aren't As Lonely As We Thought

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    The Friends of Hot Jupiters (FOHJ) project is a systematic search for planetary- and stellar-mass companions in systems that have known hot Jupiters short-period, gas-giant planets. This survey has discovered that many more hot Jupiters may have companions than originally believed.Missing FriendsFOHJ was begun with the goal of better understanding the systems that host hot Jupiters, in order to settle several longstanding issues.The first problem was one of observational statistics. We know that roughly half of the Sun-like stars nearby are in binary systems, yet weve only discovered a handful of hot Jupiters around binaries. Are binary systems less likely to host hot Jupiters? Or have we just missed the binary companions in the hot-Jupiter-hosting systems weve seen so far?An additional issue relates to formation mechanisms. Hot Jupiters probably migrated inward from where they formed out beyond the ice lines in protoplanetary disks but how?This median-stacked image, obtained with adaptive optics, shows one of the newly-discovered stellar companions to a star hosting a hot Jupiter. The projected separation is ~180 AU. [Ngo et al. 2015]Observations reveal two populations of hot Jupiters: those with circular orbits aligned with their hosts spins, and those with eccentric, misaligned orbits. The former population support a migration model dominated by local planet-disk interactions, whereas the latter population suggest the hot Jupiters migrated through dynamical interactions with distant companions. A careful determination of the companion rate in hot-Jupiter-hosting systems could help establish the ability of these two models to explain the observed populations.Search for CompanionsThe FOHJ project began in 2012 and studied 51 systems hosting known, transiting hot Jupiters with roughly half on circular, aligned orbits and half on eccentric, misaligned orbits. The survey consisted of three different, complementary components:Study 1Lead author: Heather Knutson

  19. Tilting Saturn without tilting Jupiter: Constraints on giant planet migration

    CERN Document Server

    Brasser, R

    2015-01-01

    The migration and encounter histories of the giant planets in our Solar System can be constrained by the obliquities of Jupiter and Saturn. We have performed secular simulations with imposed migration and N-body simulations with planetesimals to study the expected obliquity distribution of migrating planets with initial conditions resembling those of the smooth migration model, the resonant Nice model and two models with five giant planets initially in resonance (one compact and one loose configuration). For smooth migration, the secular spin-orbit resonance mechanism can tilt Saturn's spin axis to the current obliquity if the product of the migration time scale and the orbital inclinations is sufficiently large (exceeding 30 Myr deg). For the resonant Nice model with imposed migration, it is difficult to reproduce today's obliquity values, because the compactness of the initial system raises the frequency that tilts Saturn above the spin precession frequency of Jupiter, causing a Jupiter spin-orbit resonance...

  20. Early Results from the Juno Mission at Jupiter

    Science.gov (United States)

    Bolton, Scott; Juno Science Team

    2016-10-01

    The Juno mission is the second mission in NASA's New Frontiers program. Launched in August 2011, Juno arrived at Jupiter July 4, 2016. Juno science goals include the study of Jupiter's origin, interior structure, deep atmosphere, aurora and magnetosphere. Juno's orbit around Jupiter is a polar elliptical orbit with perijove approximately 5000 km above the visible cloud tops. The payload consists of a set of microwave antennas for deep sounding, magnetometers, gravity radio science, low and high energy charged particle detectors, electric and magnetic field radio and plasma wave experiment, ultraviolet imaging spectrograph, infrared imager and a visible camera. Early results from the mission will be presented as well as an overview of planned observations.

  1. Processing tools refinement for the JIRAM arrival to Jupiter

    Science.gov (United States)

    Moriconi, Maria L.; Noschese, R.; Adriani, A.

    2017-05-01

    The JUNO mission, launched on August 2011 with the goal of investigating the origin and evolution of Jupiter, reached Jupiter in July 2016. The months preceding the JUNO orbit insertion have been crucial for all the instrument teams to check the status and working abilities of the respective experiments. JIRAM (Jupiter Infrared Auroral Mapper), with its imager and slit spectrometer operating over the 2-5μm spectral range will attempt to reveal the deep atmospheric composition -3 to 7 bars- in hot spots, to analyze the infrared auroral emissions of the H3 + molecules ionized by the Jovian magnetosphere currents and to detect the morphology and vertical structure of the clouds. Many different processing tools are in preparation to exploit the incoming JIRAM data. Here some results pertaining to the image quality optimization and the visualizations that can be obtained from the spectrometer data management are reported.

  2. Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences

    CERN Document Server

    Komacek, Thaddeus D

    2016-01-01

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing dayside-to-nightside brightness temperature difference with increasing equilibrium temperature. Here we present a three-dimensional model that explains this relationship, in order to shed insight on the processes that control heat redistribution in tidally-locked planetary atmospheres. This three-dimensional model combines predictive analytic theory for the atmospheric circulation and dayside-nightside temperature differences over a range of equilibrium temperature, atmospheric composition, and potential frictional drag strengths with numerical solutions of the circulation that verify this analytic theory. This analytic theory shows that the longitudinal propagation of waves mediates dayside-nightside temperature differences in hot Jupiter atmospheres, analogous to the wave adjustment mechanism that regulates the thermal structure in Earth's tropics. These waves can be damped in hot Jupiter atmospheres by either r...

  3. In Situ Formation and Dynamical Evolution of Hot Jupiter Systems

    Science.gov (United States)

    Batygin, Konstantin; Bodenheimer, Peter H.; Laughlin, Gregory P.

    2016-10-01

    Hot Jupiters, giant extrasolar planets with orbital periods shorter than ˜10 days, have long been thought to form at large radial distances, only to subsequently experience long-range inward migration. Here, we offer the contrasting view that a substantial fraction of the hot Jupiter population formed in situ via the core-accretion process. We show that under conditions appropriate to the inner regions of protoplanetary disks, rapid gas accretion can be initiated by super-Earth-type planets, comprising 10-20 Earth masses of refractory material. An in situ formation scenario leads to testable consequences, including the expectation that hot Jupiters should frequently be accompanied by additional low-mass planets with periods shorter than ˜100 days. Our calculations further demonstrate that dynamical interactions during the early stages of planetary systems’ lifetimes should increase the inclinations of such companions, rendering transits rare. High-precision radial velocity monitoring provides the best prospect for their detection.

  4. 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...

  5. Formation of Jets and Equatorial Superrotation on Jupiter

    CERN Document Server

    Schneider, Tapio

    2008-01-01

    The zonal flow in Jupiter's upper troposphere is organized into alternating retrograde and prograde jets, with a prograde (superrotating) jet at the equator. Existing models posit as the driver of the flow either differential radiative heating of the atmosphere or intrinsic heat fluxes emanating from the deep interior; however, they do not reproduce all large-scale features of Jupiter's jets and thermal structure. Here it is shown that the difficulties in accounting for Jupiter's jets and thermal structure resolve if the effects of differential radiative heating and intrinsic heat fluxes are considered together, and if upper-tropospheric dynamics are linked to a magnetohydrodynamic (MHD) drag that acts deep in the atmosphere. Baroclinic eddies generated by differential radiative heating can account for the off-equatorial jets; meridionally propagating equatorial Rossby waves generated by intrinsic convective heat fluxes can account for the equatorial superrotation. The zonal flow extends deeply into the atmos...

  6. In Situ Formation and Dynamical Evolution of Hot Jupiter Systems

    CERN Document Server

    Batygin, Konstantin; Laughlin, Gregory P

    2015-01-01

    Hot Jupiters, giant extrasolar planets with orbital periods shorter than ~10 days, have long been thought to form at large radial distances, only to subsequently experience long-range inward migration. Here, we propose that in contrast with this picture, a substantial fraction of the hot Jupiter population formed in situ via the core accretion process. We show that under conditions appropriate to the inner regions of protoplanetary disks, rapid gas accretion can be initiated by Super-Earth type planets, comprising 10-20 Earth masses of refractory composition material. An in situ formation scenario leads to testable consequences, including the expectation that hot Jupiters should frequently be accompanied by additional low-mass planets with periods shorter than ~100 days. Our calculations further demonstrate that dynamical interactions during the early stages of planetary systems' lifetimes should increase the inclinations of such companions, rendering transits rare. High-precision radial velocity monitoring p...

  7. Galileo's first images of Jupiter and the Galilean satellites

    Science.gov (United States)

    Belton, M.J.S.; Head, J. W.; Ingersoll, A.P.; Greeley, R.; McEwen, A.S.; Klaasen, K.P.; Senske, D.; Pappalardo, R.; Collins, G.; Vasavada, A.R.; Sullivan, R.; Simonelli, D.; Geissler, P.; Carr, M.H.; Davies, M.E.; Veverka, J.; Gierasch, P.J.; Banfield, D.; Bell, M.; Chapman, C.R.; Anger, C.; Greenberg, R.; Neukum, G.; Pilcher, C.B.; Beebe, R.F.; Burns, J.A.; Fanale, F.; Ip, W.; Johnson, T.V.; Morrison, D.; Moore, J.; Orton, G.S.; Thomas, P.; West, R.A.

    1996-01-01

    The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on lo. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution.

  8. A transition in the composition of clouds in hot Jupiters

    CERN Document Server

    Parmentier, Vivien; Showman, Adam P; Morley, Caroline V; Marley, Mark S

    2016-01-01

    Over a large range of equilibrium temperatures, clouds shape the transmission spectrum of hot Jupiter atmospheres, yet their composition remains unknown. Recent observations show that the \\emph{Kepler} lightcurves of some hot Jupiters are asymmetric: for the hottest planets, the lightcurve peaks before secondary eclipse, whereas for planets cooler than $\\sim1900\\,\\rm K$, it peaks after secondary eclipse. In this paper we use the thermal structure from 3D global circulation models to determine the expected cloud distribution and \\emph{Kepler} lightcurves of hot Jupiters. We demonstrate that the change from a visible lightcurve dominated by thermal emission to one dominated by scattering (reflection) naturally explains the observed trend from negative to positive offset. For the cool planets the presence of an asymmetry in the \\emph{Kepler} lightcurve is a telltale sign of the cloud composition, because each cloud species can produce an offset only over a narrow range of effective temperatures. Silicate clouds ...

  9. Atmospheric Circulation on Hot Jupiters: Modeling and Observable Signatures

    Science.gov (United States)

    Rauscher, Emily Christine

    2010-12-01

    Hot Jupiters are unlike any planets in our Solar System and yet one of the most common types of extrasolar planet discovered. These gas giants orbit their parent stars with periods of a few days. Expected to be tidally locked into synchronous rotation, hot Jupiters experience intense, asymmetric heating from stellar irradiation, such that day-night temperature contrasts could reach hundreds of degrees Kelvin. This unique state of radiative forcing, as well as the slow rotation rates of these planets, places hot Jupiters within a new regime of atmospheric circulation. Hot Jupiters have also been the first type of extrasolar planet with direct detections of their atmospheres, through measurements of emitted, reflected, and transmitted light. This thesis investigates observational methods to distinguish between various atmospheric models, observational signatures of potential atmospheric variability, and presents a three dimensional model with which to study hot Jupiter circulation patterns. First, we find that eclipse mapping is a technique that can be used to image the day sides of these planets and although this is beyond the ability of current instruments, it will be achievable with future missions, such as the James Webb Space Telescope. Second, we consider the signatures of large-scale atmospheric variability in measurements of secondary eclipses and thermal orbital phase curves. For various models we predict the amount of variation in eclipse depth, and the amplitudes and detailed shapes of phase curves. Lastly, we develop a three-dimensional model of hot Jupiter atmospheric dynamics with simplified forcing and adopt a set-up nearly identical to work by another group to facilitate code inter-comparison. Our results are broadly consistent with theirs, with a transonic flow and the hottest region of the atmosphere advected eastward of the substellar point. However, we note important differences and identify areas of concern for future modeling efforts.

  10. Measuring Jupiter's water abundance by Juno: the link between interior and formation models

    CERN Document Server

    Helled, Ravit

    2014-01-01

    The JUNO mission to Jupiter is planned to measure the water abundance in Jupiter's atmosphere below the cloud layer. This measurement is important because it can be used to reveal valuable information on Jupiter's origin and its composition. In this paper we discuss the importance of this measurement, the challenges in its interpretation, and address how it can be connected to interior and formation models of Jupiter.

  11. Launch Period Development for the Juno Mission to Jupiter

    Science.gov (United States)

    Kowalkowski, Theresa D.; Johannesen, Jennie R.; Lam, Try

    2008-01-01

    The Juno mission to Jupiter is targeted to launch in 2011 and would reach the giant planet about five years later. The interplanetary trajectory is planned to include two large deep space maneuvers and an Earth gravity assist a little more than two years after launch. In this paper, we describe the development of a 21-day launch period for Juno with the objective of keeping overall launch energy and delta-V low while meeting constraints imposed on Earth departure, the deep space maneuvers' timing and geometry, and Jupiter arrival.

  12. Recent Simulations of the Late Stages Growth of Jupiter

    Science.gov (United States)

    Lissauer, Jack J.; D'Angelo, Gennaro; Hubickyj, Olenka

    2012-01-01

    Presented by Lissauer et al. (2009, Icarus 199, 338) are used to test the model of capture of Jupiter's irregular satellites within proto-Jupiter's distended and thermally-supported envelope. We find such capture highly unlikely, since the envelope shrinks too slowly for a large number of moons to be retained, and many of those that would be retained would orbit closer to the planet than do the observed Jovian irregulars. Our calculations do not address (and therefore do not exclude) the possibility that the irregular satellites were captured as a result of gas drag within a circumjovian disk. Support for this research from NASA Outer Planets Research Program is gratefully acknowledged.

  13. THE JOINT ESA-NASA EUROPA JUPITER SYSTEM MISSION (EJSM)

    Science.gov (United States)

    Lebreton, J.; Pappalardo, R. T.; Blanc, M.; Bunce, E. J.; Dougherty, M. K.; Erd, C.; Grasset, O.; Greeley, R.; Johnson, T. V.; Clark, K. B.; Prockter, L. M.; Senske, D. A.

    2009-12-01

    The joint "Europa Jupiter System Mission" (EJSM) is an international mission under study in collaboration between NASA and ESA. Its goal is to study Jupiter and its magnetosphere, the diversity of the Galilean satellites, the physical characteristics, composition and geology of their surfaces. Europa and Ganymede are two primary targets of the mission. The reference mission architecture consists of the NASA-led Jupiter Europa Orbiter (JEO) and the ESA-led Jupiter Ganymede Orbiter (JGO). The two primary goals of the mission are i) to determine whether the Jupiter system harbors habitable worlds and ii) to characterize the processes within the Jupiter system. The science objectives addressing the first goal are to: i) characterize and determine the extent of subsurface oceans and their relations to the deeper interior, ii) characterize the ice shells and any subsurface water, including the heterogeneity of the ice, and the nature of surface-ice-ocean exchange; iii) characterize the deep internal structure, differentiation history, and (for Ganymede) the intrinsic magnetic field; iv) compare the exospheres, plasma environments, and magnetospheric interactions; v) determine global surface composition and chemistry, especially as related to habitability; vi) understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ exploration. The science objectives for addressing the second goal are to: i) understand the Jovian satellite system, especially as context for Europa and Ganymede; ii) evaluate the structure and dynamics of the Jovian atmosphere; iii) characterize processes of the Jovian magnetodisk/magnetosphere; iv) determine the interactions occurring in the Jovian system; and v) constrain models for the origin of the Jupiter system. Both spacecraft would carry a complement of 11-12 instruments launch separately in 2020 and use a Venus-Earth-Earth Gravity Assist (VEEGA

  14. The EJSM Jupiter-Europa Orbiter: Science Objectives

    Science.gov (United States)

    Pappalardo, R. T.; Blanc, M.; Clark, K.; Greeley, R.; Hendrix, A. R.; Lebreton, J.-P.

    2008-09-01

    Europa is believed to shelter an ocean between its geodynamically active icy shell and its rocky mantle, where the conditions for habitability may be fulfilled. With a warm, salty, water ocean and plausible chemical energy sources, Europa is the astrobiological archetype for icy satellite habitability. It is also a geophysical wonderland of interrelated ice shell processes that are intimately related to the ocean and tides, and of complex interactions among its interior, surface, atmosphere, and magnetospheric environments. The Jupiter-Europa Orbiter (JEO) is one component of the proposed multi-spacecraft Europa Jupiter System Mission (EJSM). We focus here on the science objectives and heritage of JEO.

  15. Launch Period Development for the Juno Mission to Jupiter

    Science.gov (United States)

    Kowalkowski, Theresa D.; Johannesen, Jennie R.; Lam, Try

    2008-01-01

    The Juno mission to Jupiter is targeted to launch in 2011 and would reach the giant planet about five years later. The interplanetary trajectory is planned to include two large deep space maneuvers and an Earth gravity assist a little more than two years after launch. In this paper, we describe the development of a 21-day launch period for Juno with the objective of keeping overall launch energy and delta-V low while meeting constraints imposed on Earth departure, the deep space maneuvers' timing and geometry, and Jupiter arrival.

  16. Ultraviolet Studies of Jupiter's Hydrocarbons and Aerosols from Galileo

    Science.gov (United States)

    Gladstone, G. Randall

    2001-01-01

    This is the final report for this project. The purpose of this project was to support PI Wayne Pryor's effort to reduce and analyze Galileo UVS (Ultraviolet Spectrometer) data under the JSDAP program. The spectral observations made by the Galileo UVS were to be analyzed to determine mixing ratios for important hydrocarbon species (and aerosols) in Jupiter's stratosphere as a function of location on Jupiter. Much of this work is still ongoing. To date, we have concentrated on analyzing the variability of the auroral emissions rather than the absorption signatures of hydrocarbons, although we have done some work in this area with related HST-STIS data.

  17. Unmasking Europa the search for life on Jupiter's ocean moon

    CERN Document Server

    Greenberg, Richard

    2008-01-01

    Jupiter's ice moon Europa is widely regarded as the most likely place to find extraterrestrial life. This book tells the engaging story of Europa, the oceanic moon. It features a large number of stunning images of the ocean moon's surface, clearly displaying the spectacular crack patterns, extensive rifts and ridges, and refrozen pools of exposed water filled with rafts of displaced ice. Coverage also features firsthand accounts of Galileo's mission to Jupiter and its moons. The book tells the rough and tumble inside story of a very human enterprise in science that lead to the discovery of a f

  18. Effect of transient solar wind pulses on atmospheric heating at Jupiter

    CERN Document Server

    Yates, J N; Guio, P

    2013-01-01

    Previously, we have presented the first study to investigate the response of the Jovian thermosphere to transient variations in solar wind dynamic pressure, using a coupled, azimuthally symmetric global circulation model coupled with a simple magnetosphere model. This work (Yates et al., 2013, submitted) described the response of thermospheric flows, momentum sources, and the magnetosphere-ionosphere coupling currents to transient compressions and expansions in the magnetosphere. The present study describes the response of thermospheric heating, cooling and the auroral emissions to the aforementioned transient events. We find that transient compressions and expansions, on time scales = 25 K and a ~2000 TW increase in the total power dissipated in the thermosphere. In terms of auroral processes, transient compressions increase main oval UV emission by a factor of ~4.5 whilst transient expansions increase this main emission by a more modest 37%. Both types of transient event cause shifts in the position of the ...

  19. Temporally Varying Ethylene Emission on Jupiter

    Science.gov (United States)

    Romani, Paul N.; Jennings, Donald E.; Bjoraker, Gordon L.; Sada, Pedro V.; McCabe. Geprge; Boyle, Robert J.

    2008-01-01

    Ethylene (C2H4) emission has been measured in the poles and equator of Jupiter. The 949 cm(sup -1) spectra were recorded with a high resolution spectrometer at the McMath-Pierce telescope at Kitt Peak in October-November 1998 and at the Infrared Telescope Facility at Mauna Kea in June 2000. C2H4 is an important product of methane chemistry in the outer planets. Knowledge of its abundance can help discriminate among the various proposed sets of CH4 photolysis branching ratios at Ly-alpha, and determine the relative importance of the reaction pathways that produce C2H2 and C2H6. In the equatorial region the C2H4 emission is weak, and we were only able to detect it at high air-mass, near the limb. We derive a peak equatorial molar abundance of C2H4 of 4.5 x 10(exp -7) - 1.7 x 10(exp -6) near 2.2 x 10(exp -3) mbar, with a total column of 5.7 x 10(exp 14) - 2.2 x 10(exp 15) molecules cm(exp -2) above 10 mbar depending upon choice of thermal profile. We observed enhanced C2H4 emission from the poles in the regions where auroras are seen in X-ray, UV, and near infrared images. In 2000 we measured a short-term change in the distribution of polar C2H4 emission; the emission in the north IR auroral "hot spot" decreased by a factor of three over a two-day interval. This transient its contribution peak at 5-10 microbar suggests that the polar e is primarily a thermal effect coupled with vertical transport. Comparing our observations from Kitt Peak and Mauna Kea shows that the C2H4 emission of the northern non-"hot spot" auroral regions did not change over the three-year period while that in the southern polar regions decreased.

  20. Surface Irradiation of Jupiter's Moon Europa

    Science.gov (United States)

    Rubin, M.; Tenishev, V.; Combi, M. R.; Jia, X.; Hansen, K. C.; Gombosi, T. I.

    2010-12-01

    Jupiter’s moon Europa has a complex and tightly coupled interaction with the Jovian magnetosphere. Neutral gas of the moon’s exosphere is ionized and picked up by the corotating plasma that sweeps past Europa at a relative velocity of almost 100 km/s. This pick-up process alters the magnetic and electric field topology around Europa, which in turn affects the trajectories of the pick-up ions as well as the thermal and hot magnetospheric ions that hit the moon’s icy surface. In turn these surface-impinging ions are the responsible source for the sputtered neutral atmosphere, which itself is again crucial for the exospheric mass loading of the surrounding plasma. We use the magnetohydrodynamics (MHD) model BATSRUS to model the interaction of Europa with the Jovian magnetosphere. The model accounts for the exospheric mass loading, ion-neutral charge exchange, and ion-electron recombination [Kabin et al. (J. Geophys. Res., 104, A9, 19,983-19,992, 1999)]. The derived magnetic and electric fields are then used in our Test Particle Monte Carlo (TPMC) model to integrate individual particle trajectories under the influence of the Lorentz force. We take the measurements performed by Galileo’s Energetic Particle Detector (EPD) [Williams et al. (Sp. Sci. Rev. 60, 385-412, 1992) and Cooper et al. (Icarus 149, 133-159, 2001)] and the Plasma Analyzer (PLS) [Paterson et al. (J. Geophys. Res., 104, A10, 22,779-22,791, 1999)] as boundary conditions. Using a Monte Carlo technique allows to individually track ions in a wide energy range and to individually calculate their energy deposition on the moon’s surface. The sputtering yield is a function of incident particle type, energy, and mass. We use the measurements performed by Shi et al. (J. Geophys. Res., 100, E12, 26,387-26,395, 1995) to turn the modeled impinging ion flux into a neutral gas production rate at the surface. We will show preliminary results of this work with application to the missions to the Jupiter system

  1. Making Space Travel to Jupiter Possible

    Science.gov (United States)

    Barker, Samuel P.

    2004-01-01

    From man landing on the moon to a simple satellite being launched into orbit, many incredible space accomplishments have been witnessed by us all. However, what goes un-noticed to the common man is the extensive research and testing that lasts months, years, and even decades. Much of this required research just so happens to take place in the corridors of the Glen Research Center building number 49. In the Advanced Materials division of G.R.C., a number of researchers have the responsibility of discovering which metal, ceramic, or polymer is best for a specific application. Under the guidance of mentor extraordinaire Frank Ritzert, I am involved in many critical projects dealing with refractory metals, two of which I will mention in this report. The Jupiter Icy Moons Orbiter (JIMO) project actually was under full swing back in the 50's and early 60's. To enable the 14 year trek to the icy moons of Europa, Callisto, and Ganymede, nuclear propulsion methods were selected. Due to the extreme temperature of the reactor and the extended time period, a refractory metal would need to be implemented. After years of research and progress, the program was suddenly canceled. About a decade ago, the JIMO project was re-instated and now has a goal for departure around 2014. However, a few obstacles lie in our way concerning the use of refractory metals. In certain areas of the orbiter a joint is required between the refractories and other less dense metals. Two of these joints are with nickel based super alloys. Being an intern for Frank Ritzert, the refractory metals expert, I have the opportunity to develop the best method to braze refractory metals to Nickel 201. This involves the actual brazing, electron microscopy and reporting the results. My second project involves a certain part of the orbiter where Niobium 1Zirconium, a refractory metal, is joined with Hastelloy-X a Ni based metal. Small quantities of oxygen, helium and other impurities in the Ni alloy could diffuse

  2. 77 FR 63722 - Special Local Regulations; Palm Beach World Championship, Atlantic Ocean; Jupiter, FL

    Science.gov (United States)

    2012-10-17

    ..., Atlantic Ocean; Jupiter, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast... Indiantown Road and Donald Ross Road, just offshore of Jupiter, Florida during the Palm Beach World... will be held on the waters of the Atlantic Ocean, just offshore of Jupiter, Florida. The high...

  3. 76 FR 24513 - Public Land Order No. 7765; Partial Revocation Jupiter Inlet Lighthouse Withdrawal; Florida

    Science.gov (United States)

    2011-05-02

    ... Bureau of Land Management Public Land Order No. 7765; Partial Revocation Jupiter Inlet Lighthouse... Management to continue to be managed as part of the Jupiter Inlet Lighthouse Outstanding Natural Area. DATES... Resource Act of 2008 (43 U.S.C. 1787), which created the Jupiter Inlet Lighthouse Outstanding Natural...

  4. Thermospheric density estimation and responses to the March 2013 geomagnetic storm from GRACE GPS-determined precise orbits

    Science.gov (United States)

    Calabia, Andres; Jin, Shuanggen

    2017-02-01

    The thermospheric mass density variations and the thermosphere-ionosphere coupling during geomagnetic storms are not clear due to lack of observables and large uncertainty in the models. Although accelerometers on-board Low-Orbit-Earth (LEO) satellites can measure non-gravitational accelerations and derive thermospheric mass density variations with unprecedented details, their measurements are not always available (e.g., for the March 2013 geomagnetic storm). In order to cover accelerometer data gaps of Gravity Recovery and Climate Experiment (GRACE), we estimate thermospheric mass densities from numerical derivation of GRACE determined precise orbit ephemeris (POE) for the period 2011-2016. Our results show good correlation with accelerometer-based mass densities, and a better estimation than the NRLMSISE00 empirical model. Furthermore, we statistically analyze the differences to accelerometer-based densities, and study the March 2013 geomagnetic storm response. The thermospheric density enhancements at the polar regions on 17 March 2013 are clearly represented by POE-based measurements. Although our results show density variations better correlate with Dst and k-derived geomagnetic indices, the auroral electroject activity index AE as well as the merging electric field Em picture better agreement at high latitude for the March 2013 geomagnetic storm. On the other side, low-latitude variations are better represented with the Dst index. With the increasing resolution and accuracy of Precise Orbit Determination (POD) products and LEO satellites, the straightforward technique of determining non-gravitational accelerations and thermospheric mass densities through numerical differentiation of POE promises potentially good applications for the upper atmosphere research community.

  5. A Simulation Study of the Thermosphere Mass Density Response to Substorms Using GITM Model

    Science.gov (United States)

    Liu, X.; Ridley, A. J.

    2014-12-01

    The temporal and spatial variations of the thermosphere mass density during a variety of idealized substorms were investigated using the Global Ionosphere Thermosphere Model (GITM) simulation and Challenging Minisatellite Payload (CHAMP) satellite. From the GITM simulation, the maximum mass density perturbation of an idealized substorm with a peak variation of Hemispheric Power (HP) Index of 50 GW and interplanetary magnetic field (IMF) Bz of -2 nT was ~14% about 50 min after the substorm onset in the nightside sector of the aurora zone. About 110 min after onset, a negative mass density perturbation (~-5%) occurred in the night sector, which was consistent with the mass density measurement of the CHAMP satellite. Further investigation suggests that a large scale in situ gravity wave was generated in the aurora zone and propagated to the mid and low latitudes. Simulations with IMF Bz changes, with HP being constant and HP changing and IMF Bz being constant were run to investigate any nonlinearities in the combined response. The mass density perturbation due the IMF Bz variation peaks in the dusk sector and the density perturbation due to HP input peaks in the nightside sector. The non-linear of the mass density response to different energy input is less than 6%. The thermospheric mass density at higher altitudes is more sensitive to the Joule heating energy input. The change in hemisphere power adds electron density to lower altitudes, so the heating due to the HP change is at lower altitudes than the heating due to the IMF Bz change. This causes the density change due to the HP change to be larger than the density change due to the IMF change.

  6. A two-dimensional global simulation study of inductive-dynamic magnetosphere-ionosphere/thermosphere coupling

    Science.gov (United States)

    Tu, J.; Song, P.

    2016-12-01

    We have developed a new numerical simulation model of the ionosphere/thermosphere by using an inductive-dynamic approach (including self-consistent solutions of Faraday's law and retaining inertia terms in ion momentum equations), that is, based on magnetic field B and plasma velocity v (B, v paradigm), which is distinctive from the conventional modeling based on electric field E and current j. The model solves self-consistently time-dependent continuity, momentum, and energy equations for multiple species of ions and neutrals including photochemistry, and Maxwell's equations. The governing equations solved in the model are a set of multifluid-collisional-Hall MHD equations which are one of unique features of our ionosphere/thermosphere model. With such an inductive-dynamic approach, not only sound wave mode but also all possible MHD wave modes are retained in the solutions of the governing equations so that the dynamic coupling between the magnetosphere and ionosphere and among different regions of the ionosphere can be self-consistently investigated. In the present study, we demonstrate dynamic propagation of field-aligned currents and ionospheric electric field carried by Alfven waves, as well as formation of closure horizontal currents (Pedersen currents in the E-region), indicating that the M-I coupling is via the Alfven waves instead of the field-aligned currents or electric field mapping. The simulation results also show that the Poynting flux and strongest energy dissipation in the ionosphere/thermosphere is in the regions of the largest ion velocities and not necessarily in the auroral oval where the field-aligned currents reside. The frictional heating increases plasma temperature and thus drives ion upflows. The frictional heating also increase neutral temperature and produces neutral upflows but in a much longer time scale. Furthermore, the coupling of high-to-low latitude ionosphere is investigated in terms of propagation of fast MHD waves.

  7. Comparison of high-latitude thermospheric meridional winds II: combined FPI, radar and model climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, E.M.; Aruliah, A.; Mueller-Wodarg, I.C.F.; Aylward, A. [Atmospheric Physics Lab., Univ. Coll. London, London (United Kingdom)

    2004-07-01

    The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4 N, 20.4 E) has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM) (Hedin et al., 1988) and the numerical coupled thermosphere and ionosphere model (CTIM) are compared to the measured behaviour at kiruna, as a single site example. The empirical International Reference Ionosphere (IRI) model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using fabry-perot interferometers (FPI), together with 2 separate techniques applied to the European incoherent scatter radar (EISCAT) database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR) derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes. (orig.)

  8. Energy Budget of the Thermosphere and Mesosphere from 15 Years of SABER Observations

    Science.gov (United States)

    Hunt, L. A.; Mlynczak, M. G.; Marshall, B. T.; Russell, J. M., III

    2016-12-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite has provided nearly 15 years of continuous measurements in the mesosphere and thermosphere and operations are ongoing. The SABER instrument has performed exceptionally well since its launch in December 2001, and several more years of observations are eagerly anticipated. SABER is a limb-scanning instrument that makes vertical profile measurements of infrared radiance in ten channels chosen to permit retrieval or derivation of a variety of data products. These include radiative emission of NO at 5.3 μm and CO2 at 15 μm, two key components that govern radiative cooling of the atmosphere above 100 km. Other channels provide information about the thermal structure and elements of the energy budget of the upper mesosphere. From SABER radiances, we determine amounts of atomic oxygen and hydrogen, radiative cooling by CO2, solar heating by O3 and O2, and chemical heating from a suite of exothermic reactions over the vertical range of 65-100 km. We have observed changes in the energy budgets of these regions from mid-solar cycle 23 to the current downturn in solar cycle 24, encompassing portions of two very different solar cycles and the unusually long solar minimum between them. This talk focuses on the natural variability in the composition and energy budget of the mesosphere and lower thermosphere imposed by the variability of the Sun over the past 15 years.

  9. Intradiurnal wind variations observed in the lower thermosphere over the South Pole

    Directory of Open Access Journals (Sweden)

    Y. I. Portnyagin

    Full Text Available The first meteor radar measurements of meridional winds in the lower thermosphere (about 95 ± 5 km, along four azimuth directions: 0°, 90°E, 180° and 90°W; approximately 2° from the geographic South Pole were made during two observational campaigns: January 19, 1995-January 26, 1996, and November 21, 1996-January 27, 1997. Herein we report analyses of the measurement results, obtained during the first campaign, which cover the whole one-year period, with particular emphasis on the transient nature and seasonal behavior of the main parameters of the intradiurnal wind oscillations. To analyze the data, two complementary methods are used: the well-known periodogram (FFT technique and the S-transform technique. The most characteristic periods of the intradiurnal oscillations are found to be rather uniformly spread between about 7 h and 12 h. All of these oscillations are westward-propagating with zonal wave number s=1 and their usual duration is confined to several periods. During the austral winter season the oscillations with periods less than 12 h are the most intensive, while during summer season the 12-h oscillations dominate. Lamb waves and internal-gravity wave propagation, non-linear interaction of the short-period tides, excitation in situ of the short period waves may be considered as possible processes which are responsible for intradiurnal wind oscillations in the lower thermosphere over South Pole.

    Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides

  10. Effects of various solar indices on accuracy of Earth’s thermospheric neutral density models

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Four kinds of solar indices F10.7, E10.7, S10, Mg10 and four thermospheric neutral density models, i.e., CIRA72, DTM94, NRLMSISE00 and JB2006, are discussed. The CHAMP accelerometer data are used to calculate thermospheric total mass density. Based on the comparison of the model densities with CHAMP observations, the effects of various indices on the model accuracy are detected. It is found that under quiet and moderate solar conditions (F10.7<160), all of the models’ errors are reduced about 15% by using E10.7 instead of F10.7, while under active solar conditions (F10.7>200) the error’s standard deviation using E10.7 increases quickly and causes the models’ accuracy to fall down. With regard to S10, Mg10, their effects under quiet solar conditions are inconspicuous. If under active solar conditions, they can reduce the model error’s standard deviation by 5%-10%, implying that S10, Mg10 make the model error more stable. The JB2006 model, which was constructed by multi-solar-index (F10.7, S10, Mg10), is compared with DTM94 and NRLMSISE00 based on single-solar-index. It is found that JB2006’s accuracy is better than DTM94’s, and is close to NRLMSISE00 under the quiet solar condition. During the solar burst occurring on October 26, 2003, JB2006 has been in best agreement with CHAMP observations. All in all, the new indices may improve thermospheric density models’ accuracy under some special conditions. Concretely, E10.7 may reduce the average error of models and S10, Mg10 may prevent the error’s divergence.

  11. Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

    Science.gov (United States)

    Rocchetto, M.; Waldmann, I. P.; Venot, O.; Lagage, P.-O.; Tinetti, G.

    2016-12-01

    With a scheduled launch in 2018 October, the James Webb Space Telescope (JWST) is expected to revolutionize the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parameterized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation biases the retrieved parameters considerably, overestimating the abundances by about one order of magnitude. The retrieved abundances using the parameterized profile are usually within 1σ of the true state, and we found the retrieved uncertainties to be generally larger compared to the isothermal approximation. Interestingly, we found that by using the parameterized temperature profile we could place tight constraints on the temperature structure. This opens the possibility of characterizing the temperature profile of the terminator region of hot Jupiters. Lastly, we found that assuming a constant-with-altitude mixing ratio profile is a good approximation for most of the atmospheres under study.

  12. Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

    Directory of Open Access Journals (Sweden)

    X. Liu

    2013-01-01

    Full Text Available We study the momentum deposition in the thermosphere from the dissipation of small amplitude gravity waves (GWs within a wave packet using a fully nonlinear two-dimensional compressible numerical model. The model solves the nonlinear propagation and dissipation of a GW packet from the stratosphere into the thermosphere with realistic molecular viscosity and thermal diffusivity for various Prandtl numbers. The numerical simulations are performed for GW packets with initial vertical wavelengths (λz ranging from 5 to 50 km. We show that λz decreases in time as a GW packet dissipates in the thermosphere, in agreement with the ray trace results of Vadas and Fritts (2005 (VF05. We also find good agreement for the peak height of the momentum flux (zdiss between our simulations and VF05 for GWs with initial λz ≤ 2π H in an isothermal, windless background, where H is the density scale height. We also confirm that zdiss increases with increasing Prandtl number. We include eddy diffusion in the model, and find that the momentum deposition occurs at lower altitudes and has two separate peaks for GW packets with small initial λz. We also simulate GW packets in a non-isothermal atmosphere. The net λz profile is a competition between its decrease from viscosity and its increase from the increasing background temperature. We find that the wave packet disperses more in the non-isothermal atmosphere, and causes changes to the momentum flux and λz spectra at both early and late times for GW packets with initial λz ≥ 10 km. These effects are caused by the increase in T in the thermosphere, and the decrease in T near the mesopause.

  13. Circulation in the high-latitude thermosphere due to electric fields and Joule heating

    Science.gov (United States)

    Heaps, M. G.; Megill, L. R.

    1975-01-01

    Electric fields in the earth's upper atmosphere are capable of setting the neutral atmosphere in motion via ion-neutral collisions as well as pressure gradients from resultant Joule heating. By means of simple models for the high-latitude thermosphere and electric fields a simplified set of coupled equations is solved which show that moderate electric fields, when present for a period of several hours, are capable of displacing the neutral atmosphere of the order of 50 km in the vertical, a few hundred kilometers in the north-south direction and over 1000 km in the east-west direction.

  14. Thermospheric Diagnostics Using in situ Probing by Electron-Beam-Induced Luminescence.

    Science.gov (United States)

    1980-01-30

    DITIB TO ST TE EN (o he eot ARoed fe( eor pulcrlae1itrbto 5niie I. SPEOMENT RARYNIZOTS EADADE 0 RGA LMET RJC.TS U ta. EY W St (Continue onr itey e side...to an understanding of a number of high-altitude phenomena which include: (i) the production of 4.3-um CO2 radiation in the lower thermosphere...atmospheric conditions. Cooling of N 2* by CO2 is expected to be competitive with cooling by O(3P) at altitudes Z110 km, and diffusion is expected to

  15. Semi-Empirical, First-Principles, and Hybrid Modeling of the Thermosphere to Enhance Data Assimilation

    Science.gov (United States)

    2015-10-27

    Mauersberger, K., D. C. Kayser, W. E. Potter , and A. O. Nier (1976), Seasonal variation of neutral thermospheric constituents in the Northern Hemisphere...J. Geophys. Res., 81, pp. 7–11, doi:10.1029/JA081i001p00007. [41] Mauersberger, K., W. E. Potter , and D. C. Kayser (1976), A direct measurement of...Geophys. Res., 79, p. 619, doi:10.1029/JA079i004p00619. [45] Mayr, H. G., I. Harris , and N. W. Spencer (1978), Some properties of upper atmosphere

  16. First results of ISO-SWS observations of Jupiter

    NARCIS (Netherlands)

    Encrenaz, T.; de Graauw, T.; Schaeidt, S.; Lellouch, E.; Feuchtgruber, H.; Beintema, D. A.; Bezard, B.; Drossart, P.; Griffin, M.; Heras, A.; Kessler, M.; Leech, K.; Morris, P.; Roelfsema, P. R.; Roos-Serote, M.; Salama, A.; Vandenbussche, B.; Valentijn, E. A.; Davis, G. R.; Naylor, D. A.

    1996-01-01

    The spectrum of Jupiter has been recorded between 2.75 and 14.5 mu m with the grating mode of the Short-Wavelength Spectrometer (SWS) of ISO. The resolving power is 1500. The main preliminary results of this observation are (1) at 3 mu m, the first spectroscopic signature, probably associated with

  17. Orbits of the small inner satellites of Jupiter

    Science.gov (United States)

    Synnott, S. P.

    1984-01-01

    Voyager images led to the discovery of the three small inner satellites of Jupiter, Adrastea, Metis, and Thebe. Attention is presently given to orbital parameter estimates and associated uncertainties that have been determined from Voyager imaging data, the achievable angular accuracy of which is about 0.00005 rad.

  18. Design study for electronic system for Jupiter Orbit Probe (JOP)

    Science.gov (United States)

    Elero, B. P., Jr.; Carignan, G. R.

    1978-01-01

    The conceptual design of the Jupiter probe spectrometer is presented. Block and circuit diagrams are presented along with tabulated parts lists. Problem areas are considered to be (1) the schedule, (2) weight limitations for the electronic systems, and (3) radiation hardness of the electronic devices.

  19. Deciphering Jupiter's atmospheric dynamics using the upcoming Juno gravity measurements

    Science.gov (United States)

    Kaspi, Yohai; Galanti, Eli

    2016-07-01

    This summer, the Juno spacecraft will arrive at Jupiter in course for close flybys of the planet, obtaining a high precision gravity spectrum of Jupiter. This data can be used to estimate the depth of Jupiter's observed cloud-level wind, and decipher the possible internal flows, that might be decoupled from the surface wind. In this talk, we discuss the Juno gravity experiment, and the possible outcomes with regard to the flows on Jupiter. We show several ways in which the gravity spectrum might be used to study the large scale flows: 1. measurements of the high order even harmonics which beyond J10 are dominated by the dynamics; 2. measurements of odd gravity harmonics which have no contribution from a static planet, and therefore are a pure signature of dynamics; 3. upper limits on the depth of the surface flow can be obtained by comparing low order even harmonics from dynamical models to the difference between the measured low order even harmonics and the largest possible values of a static planet; 4. direct latitudinally varying measurements of the gravity field exerted on the spacecraft. We will discuss how these methods may be applied given the expected sensitivities of the Juno gravity experiment. In addition, we present an inverse adjoint model, which allows given the gravity data, to infer the flows that produce it. This will allow, hopefully, to make significant progress in one of the longest-standing question in planetary atmospheric dynamics regarding the nature of the flows on the giant planets.

  20. Rotating magnetospheres: transport compared at Jupiter and Saturn

    Science.gov (United States)

    Kivelson, M. G.; Southwood, D. J.; Dougherty, M. K.

    The magnetospheres of Jupiter and Saturn are dominated by the effects of rotation and the associated outward stress exerted by heavy ions picked up near the inner moons Fields and particle measurements in both systems show dramatic signatures of rotational periodicity At Jupiter the periodicity results principally from the effects of dipole tilt and the related displacements of the equatorial plasma sheet At Saturn there is little dipole tilt yet field and plasma properties vary periodically Efforts to understand how Saturn s rotational motion can be converted into what appears to be radial motion a conversion from rotation to rocking or reciprocating motion that is imposed in mechanical systems by a camshaft have recently focused on convective patterns with preferred sectors for transport see Southwood et al this session It is possible that similar effects are present at Jupiter and can account for plasma properties that have been described in terms of what has been referred to as the magnetic anomaly model Hill Goertz and Dessler 1983 This talk will use magnetometer data for the two systems to identify the possibly subtle signatures of the camshaft effect at Jupiter

  1. First Earth-based Detection of a Superbolide on Jupiter

    Science.gov (United States)

    Hueso, Ricardo; Wesley, A.; Go, C.; Perez-Hoyos, S.; Wong, M. H.; Fletcher, L. N.; Sanchez-Lavega, A.; Boslough, M. B. E.; de Pater, I.; Orton, G. S.; Simon-Miller, A. A.; Djorgovski, S. G.; Edwards, M. L.; Hammel, H. B.; Clarke, J. T.; Noll, K. S.; Yanamandra-Fisher, P. A.

    2010-10-01

    On June 3, 2010 a bolide in Jupiter's atmosphere was observed from the Earth for the first time. The flash was detected by amateur astronomers A. Wesley and C. Go observing in two wavelength ranges. We present an analysis of the light curve of those observations that allow estimating the size of the object to be significantly smaller than the SL9 and the July 2009 Jupiter impact. Observations obtained a few days later by large telescopes including HST, VLT, Keck and Gemini showed no signature of the impact in Jupiter atmosphere confirming the small size of the impact body. A nearly continuous observation campaign based on several small telescopes by amateurs astronomers might allow an empirical determination of the flux of meteoroids in Jupiter with implications for the populations of small bodies in the outer solar system and may allow a better quantification of the threat of impacting bodies to Earth. Acknowledgements: RH, ASL and SPH are supported by the Spanish MICIIN AYA2009-10701 with FEDER and Grupos Gobierno Vasco IT-464-07. LNF is supported by a Glasstone Science Fellowship at the University of Oxford.

  2. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    NARCIS (Netherlands)

    Girard, J. N.; Zarka, P.; Tasse, C.; Hess, S.; de Pater, I.; Santos-Costa, D.; Nenon, Q.; Sicard, A.; Bourdarie, S.; Anderson, J.; Asgekar, A.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.; Best, P.; Bonafede, A.; Breitling, F.; Breton, R. P.; Broderick, J. W.; Brouw, W. N.; Brüggen, M.; Ciardi, B.; Corbel, S.; Corstanje, A.; de Gasperin, F.; de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Falcke, H.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Gunst, A. W.; Hessels, J. W. T.; Hoeft, M.; Hörandel, J.; Iacobelli, M.; Juette, E.; Kondratiev, V. I.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Loose, M.; Maat, P.; Mann, G.; Markoff, S.; McFadden, R.; McKay-Bukowski, D.; Moldon, J.; Munk, H.; Nelles, A.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H.; Rowlinson, A.; Schwarz, D.; Smirnov, O.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; Vocks, C.; van Weeren, R. J.; Wijers, R. A. M. J.; Wucknitz, O.

    2016-01-01

    Context. With the limited amount of in situ particle data available for the innermost region of Jupiter's magnetosphere, Earth-based observations of the giant planets synchrotron emission remain the sole method today of scrutinizing the distribution and dynamical behavior of the ultra energetic elec

  3. Ultra-relativistic electrons in Jupiter's radiation belts.

    Science.gov (United States)

    Bolton, S J; Janssen, M; Thorne, R; Levin, S; Klein, M; Gulkis, S; Bastian, T; Sault, R; Elachi, C; Hofstadter, M; Bunker, A; Dulk, G; Gudim, E; Hamilton, G; Johnson, W T K; Leblanc, Y; Liepack, O; McLeod, R; Roller, J; Roth, L; West, R

    2002-02-28

    Ground-based observations have shown that Jupiter is a two-component source of microwave radio emission: thermal atmospheric emission and synchrotron emission from energetic electrons spiralling in Jupiter's magnetic field. Later in situ measurements confirmed the existence of Jupiter's high-energy electron-radiation belts, with evidence for electrons at energies up to 20[?]MeV. Although most radiation belt models predict electrons at higher energies, adiabatic diffusion theory can account only for energies up to around 20[?]MeV. Unambiguous evidence for more energetic electrons is lacking. Here we report observations of 13.8[?]GHz synchrotron emission that confirm the presence of electrons with energies up to 50[?]MeV; the data were collected during the Cassini fly-by of Jupiter. These energetic electrons may be repeatedly accelerated through an interaction with plasma waves, which can transfer energy into the electrons. Preliminary comparison of our data with model results suggests that electrons with energies of less than 20[?]MeV are more numerous than previously believed.

  4. First results of ISO-SWS observations of Jupiter

    NARCIS (Netherlands)

    Encrenaz, T.; de Graauw, T.; Schaeidt, S.; Lellouch, E.; Feuchtgruber, H.; Beintema, D. A.; Bezard, B.; Drossart, P.; Griffin, M.; Heras, A.; Kessler, M.; Leech, K.; Morris, P.; Roelfsema, P. R.; Roos-Serote, M.; Salama, A.; Vandenbussche, B.; Valentijn, E. A.; Davis, G. R.; Naylor, D. A.

    1996-01-01

    The spectrum of Jupiter has been recorded between 2.75 and 14.5 mu m with the grating mode of the Short-Wavelength Spectrometer (SWS) of ISO. The resolving power is 1500. The main preliminary results of this observation are (1) at 3 mu m, the first spectroscopic signature, probably associated with N

  5. The high albedo of the hot Jupiter Kepler-7b

    DEFF Research Database (Denmark)

    Demory, B.-O.; Seager, S.; Madhusudhan, N.

    2011-01-01

    . The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7 b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass...

  6. The prediction of impact of Comet SL9 on Jupiter

    Institute of Scientific and Technical Information of China (English)

    张家祥; 汪琦; 杨捷兴; 王思潮; 陈协珍

    1996-01-01

    Several predictions of the impact of Comet SL9 on Jupiter were made from April to July, 1994. The predictions are basically in agreement with actuality. The method and theory of the prediction are expounded briefly, and the predicted impact times are analyzed and compared with actually accepted impact times.

  7. EJSM Radar instruments: Natural radio noise from Jupiter

    Science.gov (United States)

    Cecconi, Baptiste; Hess, Sébastien; Zarka, Philippe; Blankenship, Donald; Bruzzone, Lorenzo; Santos-Costa, Daniel; Bougeret, Jean-Louis

    2010-05-01

    Radar instruments are part of the core payload of the Europa Jupiter System Mission (EJSM) spacecraft: NASA- led JEO (Jupiter Europa Orbiter) and ESA-led JGO (Jupiter Ganymede Orbiter). At this point of the project, several frequency bands are foreseen for radar studies between 5MHz and 50MHz. While the high frequencies (40 to 50 MHz) are clean bands since natural jovian radio emissions show a high frequency cutoff at about 40 MHz, lower frequencies are right in the middle of the intense decametric (DAM) radio emissions. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. One result from these simulations is that some portion of the orbit of Europa is clean from Non-Io DAM emissions above 22 MHz. We also review the radiation belts synchrotron emission characteristics. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation.

  8. First Earth-based Detection of a Superbolide on Jupiter

    CERN Document Server

    Hueso, R; Go, C; Perez-Hoyos, S; Wong, M H; Fletcher, L N; Sanchez-Lavega, A; Boslough, M B E; de Pater, I; Orton, G S; Simon-Miller, A A; Djorgovski, S G; Edwards, M L; Hammel, H B; Clarke, J T; Noll, K S; Yanamandra-Fisher, P A; 10.1088/2041-8205/721/2/L129

    2010-01-01

    Cosmic collisions on planets cause detectable optical flashes that range from terrestrial shooting stars to bright fireballs. On June 3, 2010 a bolide in Jupiter's atmosphere was simultaneously observed from the Earth by two amateur astronomers observing Jupiter in red and blue wavelengths. The bolide appeared as a flash of 2 s duration in video recording data of the planet. The analysis of the light curve of the observations results in an estimated energy of the impact of 0.9-4.0x10^{15} J which corresponds to a colliding body of 8-13 m diameter assuming a mean density of 2 g cm^{-3}. Images acquired a few days later by the Hubble Space Telescope and other large ground-based facilities did not show any signature of aerosol debris, temperature or chemical composition anomaly, confirming that the body was small and destroyed in Jupiter's upper atmosphere. Several collisions of this size may happen on Jupiter on a yearly basis. A systematic study of the impact rate and size of these bolides can enable an empiri...

  9. Jupiter and Super-Earth embedded in a gaseous disc

    CERN Document Server

    Podlewska, E

    2007-01-01

    In this paper we investigate the evolution of a pair of interacting planets - a Jupiter mass planet and a Super-Earth with the 5.5 Earth masses - orbiting a Solar type star and embedded in a gaseous protoplanetary disc. We focus on the effects of type I and II orbital migrations, caused by the planet-disc interaction, leading to the Super-Earth capture in first order mean motion resonances by the Jupiter. The stability of the resulting resonant system in which the Super-Earth is on the internal orbit relatively to the Jupiter has been studied numerically by means of full 2D hydrodynamical simulations. Our main motivation is to determine the Super-Earth behaviour in the presence of the gas giant in the system. It has been found that the Jupiter captures the Super-Earth into the interior 3:2 or 4:3 mean motion resonances and the stability of such configurations depends on the initial planet positions and eccentricity evolution. If the initial separation of planet orbits is larger or close to that required for t...

  10. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

    NARCIS (Netherlands)

    Girard, J. N.; Zarka, P.; Tasse, C.; Hess, S.; de Pater, I.; Santos-Costa, D.; Nenon, Q.; Sicard, A.; Bourdarie, S.; Anderson, J.; Asgekar, A.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.; Best, P.; Bonafede, A.; Breitling, F.; Breton, R. P.; Broderick, J. W.; Brouw, W. N.; Brüggen, M.; Ciardi, B.; Corbel, S.; Corstanje, A.; de Gasperin, F.; de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Falcke, H.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Gunst, A. W.; Hessels, J. W. T.; Hoeft, M.; Hörandel, J.; Iacobelli, M.; Juette, E.; Kondratiev, V. I.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Loose, M.; Maat, P.; Mann, G.; Markoff, S.; McFadden, R.; McKay-Bukowski, D.; Moldon, J.; Munk, H.; Nelles, A.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H.; Rowlinson, A.; Schwarz, D.; Smirnov, O.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; Vocks, C.; van Weeren, R. J.; Wijers, R. A. M. J.; Wucknitz, O.

    2016-01-01

    Context. With the limited amount of in situ particle data available for the innermost region of Jupiter's magnetosphere, Earth-based observations of the giant planets synchrotron emission remain the sole method today of scrutinizing the distribution and dynamical behavior of the ultra energetic

  11. An Overview of the Jupiter Europa Orbiter Concept's Europa Science Phase Orbit Design

    Science.gov (United States)

    Lock, Robert E.; Ludwinski, Jan M.; Petropoulos, Anastassios E.; Clark, Karla B.; Pappalardo, Robert T.

    2009-01-01

    Jupiter Europa Orbiter (JEO), the proposed NASA element of the proposed joint NASA-ESA Europa Jupiter System Mission (EJSM), could launch in February 2020 and conceivably arrive at Jupiter in December of 2025. The concept is to perform a multi-year study of Europa and the Jupiter system, including 30 months of Jupiter system science and a comprehensive Europa orbit phase of 9 months. This paper provides an overview of the JEO concept and describes the Europa Science phase orbit design and the related science priorities, model pay-load and operations scenarios needed to conduct the Europa Science phase. This overview is for planning and discussion purposes only.

  12. HUBBLE VIEWS ANCIENT STORM IN THE ATMOSPHERE OF JUPITER

    Science.gov (United States)

    2002-01-01

    When 17th-century astronomers first turned their telescopes to Jupiter, they noted a conspicuous reddish spot on the giant planet. This Great Red Spot is still present in Jupiter's atmosphere, more than 300 years later. It is now known that it is a vast storm, spinning like a cyclone. Unlike a low-pressure hurricane in the Caribbean Sea, however, the Red Spot rotates in a counterclockwise direction in the southern hemisphere, showing that it is a high-pressure system. Winds inside this Jovian storm reach speeds of about 270 mph. The Red Spot is the largest known storm in the Solar System. With a diameter of 15,400 miles, it is almost twice the size of the entire Earth and one-sixth the diameter of Jupiter itself. The long lifetime of the Red Spot may be due to the fact that Jupiter is mainly a gaseous planet. It possibly has liquid layers, but lacks a solid surface, which would dissipate the storm's energy, much as happens when a hurricane makes landfall on the Earth. However, the Red Spot does change its shape, size, and color, sometimes dramatically. Such changes are demonstrated in high-resolution Wide Field and Planetary Cameras 1 and 2 images of Jupiter obtained by NASA's Hubble Space Telescope, and presented here by the Hubble Heritage Project team. The mosaic presents a series of pictures of the Red Spot obtained by Hubble between 1992 and 1999. Astronomers study weather phenomena on other planets in order to gain a greater understanding of our own Earth's climate. Lacking a solid surface, Jupiter provides us with a laboratory experiment for observing weather phenomena under very different conditions than those prevailing on Earth. This knowledge can also be applied to places in the Earth's atmosphere that are over deep oceans, making them more similar to Jupiter's deep atmosphere. The Hubble images were originally collected by Amy Simon (Cornell U.), Reta Beebe (NMSU), Heidi Hammel (Space Science Institute, MIT), and their collaborators, and have been

  13. K2 Warm Jupiters with the LCOGT TECH collaboration

    Science.gov (United States)

    Shporer, Avi; Bayliss, Daniel; Cochran, William D.; Colón, Knicole D.; Dragomir, Diana; Palle, Enric; Potter, Stephen; Siverd, Robert; LCOGT TECH Collaboration

    2016-06-01

    Many transiting gas giant planets on short orbital periods (so called hot Jupiters) have larger radii than theoretically expected. Although several explanations have been proposed, none have completely solved this puzzle. As the number of known transiting planets grew a correlation was identified between gas giant radius and the stellar incident flux. Still, it is not clear whether this correlation is causation. Several questions remain and answering them will characterize in more detail this observed correlation and in turn the process responsible for the inflated radii, such as: Is the lack of inflated warm Jupiters a robust feature? What is the incident flux below which there are no inflated gas giants? How low in incident flux does this correlation stretch? These questions arise since there are only a small number of transiting gas giants with low incident flux, below about 108 erg/s/cm2, corresponding to orbital periods of about 10 days and longer for a Sun-like host star. Discovering and confirming more transiting warm Jupiters is the goal of this project, undertaken by the LCOGT Transiting Exoplanet CHaracterization (TECH) team. We are using K2 as our main source of transiting warm Jupiter candidates, with a few candidates discovered in each K2 campaign. LCOGT telescopes are being used for obtaining additional ground-based transit light curves, which are critical for confirming and refining the K2 transit ephemeris as outliers during ingress or egress of the few transit events observed by K2 can bias the measured ephemeris. Further ground-based follow-up data, including spectroscopy, radial velocities, and high angular resolution imaging, are obtained by facilities directly accessible by LCOGT TECH team members. In addition, once LCOGT’s Network of Robotic Echelle Spectrographs (NRES) are deployed in the near future they will allow obtaining spectroscopy and radial velocities with LCOGT facilities. On top of studying the inflated hot Jupiter conundrum

  14. Tracking Jupiter at microwave frequencies after the 2009 impact

    Science.gov (United States)

    Horiuchi, Shinji; García-Miró, Cristina; Rizzo, Ricardo; Forster, James; Hofstadter, Mark; Dorcey, Ryan; Jauncey, David; de Pater, Imke; Baines, Graham; Sotuela, Ioanna

    2010-05-01

    On 19 July 2009, amateur astronomer Anthony Wesley located near Canberra, Australia, discovered an anomalous dark feature near Jupiter's south pole. It was soon confirmed with additional observations that the new feature was an impact site created by an unknown object. The only other observed collision with Jupiter occurred 15 years earlier with the catastrophic impact of the Shoemaker-Levy 9 Comet (SL9). Unlike the well-predicted SL9 event, the biggest question to answer this time is whether the impact body was a comet or an asteroid. We started a campaign to track Jupiter at microwave frequencies with NASA's Deep Space Network (DSN), in Canberra, Goldstone (California), and Madrid, and the Allen Telescope Array (ATA) in California. A 34m DSN radio telescope at Goldstone was operated by students through GAVRT program. Our primary goal was first to detect molecular radio emissions possibly originating from cometary core components, such as OH, H2O, and NH3, and second to detect radio burst in non-thermal continuum emissions, as observed after the SL-9 impact 15 years ago. We used a 70m radio telescope in Canberra and another 70m in Madrid to search for molecular emissions at 1.6 GHz for OH, 22 GHz for water vapors, 23 GHz for ammonia. Several radio spectroscopy observing sessions have been successfully conducted from 23 July to 1 August. We also started continuum emission monitoring, mainly at 2.3 GHz and 8.4 GHz using 34m and 70m DSN telescopes and the ATA. At early stage of this still on-going monitoring, joint observations were conducted with two 34m telescopes in Canberra and the ATA on 30 July and 9 August in order to have long continuous time coverage and to check flux density scales using a common calibrator source. To highlight this campaign, on 22 November we undertook the Jupiter: Project 24 for the International Year of Astronomy. This campaign was over 24 hours of continuous observation of Jupiter using all three DSN complexes around the world. A couple

  15. Hubble Provides Infrared View of Jupiter's Moon, Ring, and Clouds

    Science.gov (United States)

    1997-01-01

    Probing Jupiter's atmosphere for the first time, the Hubble Space Telescope's new Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides a sharp glimpse of the planet's ring, moon, and high-altitude clouds.The presence of methane in Jupiter's hydrogen- and helium-rich atmosphere has allowed NICMOS to plumb Jupiter's atmosphere, revealing bands of high-altitude clouds. Visible light observations cannot provide a clear view of these high clouds because the underlying clouds reflect so much visible light that the higher level clouds are indistinguishable from the lower layer. The methane gas between the main cloud deck and the high clouds absorbs the reflected infrared light, allowing those clouds that are above most of the atmosphere to appear bright. Scientists will use NICMOS to study the high altitude portion of Jupiter's atmosphere to study clouds at lower levels. They will then analyze those images along with visible light information to compile a clearer picture of the planet's weather. Clouds at different levels tell unique stories. On Earth, for example, ice crystal (cirrus) clouds are found at high altitudes while water (cumulus) clouds are at lower levels.Besides showing details of the planet's high-altitude clouds, NICMOS also provides a clear view of the ring and the moon, Metis. Jupiter's ring plane, seen nearly edge-on, is visible as a faint line on the upper right portion of the NICMOS image. Metis can be seen in the ring plane (the bright circle on the ring's outer edge). The moon is 25 miles wide and about 80,000 miles from Jupiter.Because of the near-infrared camera's narrow field of view, this image is a mosaic constructed from three individual images taken Sept. 17, 1997. The color intensity was adjusted to accentuate the high-altitude clouds. The dark circle on the disk of Jupiter (center of image) is an artifact of the imaging system.This image and other images and data received from the Hubble Space Telescope are posted on the

  16. Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective.

    Science.gov (United States)

    Kones, Richard

    2010-12-09

    The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with

  17. Jupiter's Mid-Infrared Aurora: Solar Connection and Minor Constituents

    Science.gov (United States)

    Kostiuk, Theodore; Livengood, T.A.; Fast, K.E.; Hewagama, T.; Schmilling, F.; Sonnabend, G.; Delgado, J.

    2009-01-01

    High spectral resolution in the 12 pin region of the polar regions of Jupiter reveal unique information on auroral phenomena and upper stratospheric composition. Polar aurorae in Jupiter's atmosphere radiate; throughout the electromagnetic spectrum from X-ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based. spectroscopic measurements of Jupiter's northern mid-IR aurora acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane, emission brightness and solar 10.7-cm radar flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high scalar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. The spectra measured contain features that cannot be attributed to ethane and are most likely spectra of minor constituents whose molecular bands overlap the v9 band of ethane. Possible candidates are allene, propane, and other higher order hydrocarbons. These features appear to be enhanced in the active polar regions. Laboratory measurements at comparable spectral resolution of spectra of candidate molecules will be used to identify the constituents. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the NASA/ESA Europa Jupiter System Mission.

  18. Exploring the diversity of Jupiter-class planets.

    Science.gov (United States)

    Fletcher, Leigh N; Irwin, Patrick G J; Barstow, Joanna K; de Kok, Remco J; Lee, Jae-Min; Aigrain, Suzanne

    2014-04-28

    Of the 900+ confirmed exoplanets discovered since 1995 for which we have constraints on their mass (i.e. not including Kepler candidates), 75% have masses larger than Saturn (0.3 MJ), 53% are more massive than Jupiter and 67% are within 1 AU of their host stars. When Kepler candidates are included, Neptune-sized giant planets could form the majority of the planetary population. And yet the term 'hot Jupiter' fails to account for the incredible diversity of this class of astrophysical object, which exists on a continuum of giant planets from the cool jovians of our own Solar System to the highly irradiated, tidally locked hot roasters. We review theoretical expectations for the temperatures, molecular composition and cloud properties of hydrogen-dominated Jupiter-class objects under a variety of different conditions. We discuss the classification schemes for these Jupiter-class planets proposed to date, including the implications for our own Solar System giant planets and the pitfalls associated with compositional classification at this early stage of exoplanetary spectroscopy. We discuss the range of planetary types described by previous authors, accounting for (i) thermochemical equilibrium expectations for cloud condensation and favoured chemical stability fields; (ii) the metallicity and formation mechanism for these giant planets; (iii) the importance of optical absorbers for energy partitioning and the generation of a temperature inversion; (iv) the favoured photochemical pathways and expectations for minor species (e.g. saturated hydrocarbons and nitriles); (v) the unexpected presence of molecules owing to vertical mixing of species above their quench levels; and (vi) methods for energy and material redistribution throughout the atmosphere (e.g. away from the highly irradiated daysides of close-in giants). Finally, we discuss the benefits and potential flaws of retrieval techniques for establishing a family of atmospheric solutions that reproduce the

  19. Simon Marius vs. Galileo: Who First Saw Moons of Jupiter?

    Science.gov (United States)

    Pasachoff, Jay M.; Van Helden, Albert

    2016-10-01

    In his almanac for 1612 and book Mundus Iovalis of 1614, Simon Marius in Germany reported his discovery of moons around Jupiter, which he started writing down in late 1609 in the Julian calendar, which translated to 8 January 1610 in the Gregorian calendar in use by Galileo in Italy. Is Marius to be believed? Galileo certainly did not. But a Dutch jury of experts about three hundred years later reported that they validated the claim that Marius independently discovered the moons of Jupiter one day after Galileo first both saw and wrote down his discovery! There is no doubt that the names Io, Europa, Ganymede, and Callisto came from Marius (to whom they were suggested by Kepler). See JMP's Journal for the History of Astronomy article, 46(2), 218-234 (2015).Marius wrote that he had been observing the moons around Jupiter since November 1609 (Julian), using a neighboring nobleman's telescope, which would mean that he actually saw the Jupiter satellites first (though publish or perish). Whether this feat was technically possible comes down to discussions of the capabilities of telescopes in the early 17th century.The quadricentennial of Marius's book was celebrated in Nuremberg with a symposium that is now in press in German with an English translation expected. One of us (AVH) has recently prepared a complete English translation of Marius's book, superseding the partial translation made 100 years ago. There is no evidence that, whether he saw what we now call the Galilean satellites first or not, Marius appreciated their cosmological significance the way that Galileo soon did. And Marius was certainly the first to publish tables of the moons of Jupiter.We thank the Chapin Library of Williams College and the Huntington Library for assistance with first editions of Marius's 1614 book, and we thank Pierre Leich of the Simon Marius Gesellschaft for his consultations.

  20. First Results of the Juno Magnetometer Investigation in Jupiter's Magnetosphere

    Science.gov (United States)

    Connerney, Jack; Oliversen, Ronald; Espley, Jared; Kotsiaros, Stavros; Joergensen, John; Joergensen, Peter; Merano, Jose; Denver, Troelz; Benn, Mathias; Bloxham, Jeremy; Bolton, Scott; Levin, Steve

    2017-04-01

    The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, after a Jupiter Orbit Insertion (JOI) main engine burn lasting 35 minutes. Juno's science instruments were not powered during the critical maneuver sequence ( 5 days) but were fully operational shortly afterward. The 53.5-day capture orbit provides Juno's science instruments with the opportunity to sample the Jovian environment close up (to 1.06 Jovian radii, Rj) and in polar orbit extending to the outer reaches of the Jovian magnetosphere. Jupiter's gravity and magnetic fields will be globally mapped with unprecedented accuracy as Juno conducts a study of Jupiter's interior structure and composition, as well as the first comprehensive exploration of the polar magnetosphere. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. The first few periapsis passes available to date revealed an extraordinary spatial variation of the magnetic field close to the planet's surface, suggesting that Juno may be sampling the field closer to the dynamo region than widely anticipated, i.e., portending a dynamo surface extending to relatively large radial distance ( 0.9Rj?). We present the first observations of Jupiter's magnetic field obtained in close proximity to the planet, and speculate on what wonders await as more longitudes are drawn across the global map (32 polar orbits separated by designed to acquire.

  1. Evidence for Two Hot-Jupiter Formation Paths

    Science.gov (United States)

    Nelson, Benjamin E.; Ford, Eric B.; Rasio, Frederic A.

    2017-09-01

    Disk migration and high-eccentricity migration are two well-studied theories to explain the formation of hot Jupiters. The former predicts that these planets can migrate up until the planet-star Roche separation ({a}{Roche}) and the latter predicts they will tidally circularize at a minimum distance of 2 {a}{Roche}. Considering long-running radial velocity and transit surveys have identified a couple hundred hot Jupiters to date, we can revisit the classic question of hot-Jupiter formation in a data-driven manner. We approach this problem using data from several exoplanet surveys (radial velocity, Kepler, HAT, and WASP) allowing for either a single population or a mixture of populations associated with these formation channels, and applying a hierarchical Bayesian mixture model of truncated power laws of the form {x}γ -1 to constrain the population-level parameters of interest (e.g., location of inner edges, γ, mixture fractions). Within the limitations of our chosen models, we find that the current radial velocity and Kepler sample of hot Jupiters can be well explained with a single truncated power-law distribution with a lower cutoff near 2 {a}{Roche}, a result that still holds after a decade, and γ =-0.51{+/- }0.200.19. However, the HAT and WASP data show evidence for multiple populations (Bayes factor ≈ {10}21). We find that 15{+/- }69 % reside in a component consistent with disk migration (γ =-0.04{+/- }1.270.53) and 85{+/- }96 % in one consistent with high-eccentricity migration (γ =-1.38{+/- }0.470.32). We find no immediately strong connections with some observed host star properties and speculate on how future exoplanet surveys could improve upon hot-Jupiter population inference.

  2. Jupiter's Phase Variations from Cassini: a testbed for future direct-imaging missions

    Science.gov (United States)

    Mayorga, Laura; Jackiewicz, Jason; Rages, Kathy; West, Robert; Knowles, Ben; Marley, Mark; Lewis, Nikole

    2016-10-01

    Phase curves are important for our understanding of the energy balance and scattering behavior of an exoplanet's atmosphere. In preparation for future direct-imaging missions of Jupiter-like planets, we present phase curves of Jupiter from 0--150 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. We demonstrate and confirm that Jupiter is not well represented by a Lambertian phase function and that its color is more variable with phase angle than predicted by Jupiter-like models. This indicates that a Jupiter-twin observed near quadrature may not be as straightforward to classify as a Jupiter-like planet.

  3. Jupiter's Phase Variations from Cassini: a testbed for future direct-imaging missions

    Science.gov (United States)

    Mayorga, Laura; Jackiewicz, Jason; Rages, Kathy; West, Robert A.; Knowles, Ben; Lewis, Nikole K.; Marley, Mark S.

    2017-01-01

    Phase curves are important for our understanding of the energy balance and scattering behavior of an exoplanet's atmosphere. In preparation for future direct-imaging missions of Jupiter-like planets, in particular WFIRST, we present phase curves of Jupiter from 0--150 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. We demonstrate and confirm that Jupiter is not well represented by a Lambertian phase function and that its color is more variable with phase angle than predicted by Jupiter-like models. This indicates that a Jupiter-twin observed near quadrature may not be as straightforward to classify as a Jupiter-like planet and comment on the implications for future missions.

  4. A simulation study of the thermosphere mass density response to substorms using GITM

    Science.gov (United States)

    Liu, Xianjing; Ridley, Aaron

    2015-09-01

    The temporal and spatial variations of the thermospheric mass density during a series of idealized substorms were investigated using the Global Ionosphere Thermosphere Model (GITM). The maximum mass density perturbation of an idealized substorm with a peak variation of hemispheric power (HP) of 50 GW and interplanetary magnetic field (IMF) Bz of -2 nT was ~14% about 50 min after the substorm onset in the nightside sector of the auroral zone. The mass density response to different types of energy input has a strong local time dependence, with the mass density perturbation due to only an IMF Bz variation peaking in the dusk sector and the density perturbation due to only HP variation peaks in the nightside sector. Simulations with IMF Bz changes only and HP changes only showed that the system behaves slightly nonlinearly when both IMF and HP variations are included (a maximum of 6% of the nonlinearity) and that the nonlinearity grows with energy input. The neutral gas heating rate due to Joule heating was of same magnitude as the heating rate due to precipitation, but the majority of the temperature enhancement due to the heating due to precipitation occurs at lower altitude as compared to the auroral heating. About 110 min after onset, a negative mass density perturbation (~-5%) occurred in the night sector, which was consistent with the mass density measurement of the CHAMP satellite.

  5. High-latitude energy input and its impact on the thermosphere

    Science.gov (United States)

    Lu, G.; Richmond, A. D.; Lühr, H.; Paxton, L.

    2016-07-01

    This paper presents a quantitative assessment of high-latitude energy input and its partitioning in the polar cap by synthesizing various space and ground-based observations during the 17 January 2005 geomagnetic storm. It was found that Joule heating is the primary form of magnetospheric energy input, especially during active times when the hemispheric-integrated Joule heating can be an order of magnitude larger than the hemispheric-integrated auroral power. Most of magnetospheric energy is dissipated in the auroral zone rather than in the polar cap. On average, only about 22-25% of the total hemispheric energy input is dissipated into the polar cap region bordered by the convection reversal boundary (CRB) and the poleward auroral flux boundary (FXB). The impact of high-latitude energy input was also investigated to unveil the causal relationship between Joule heating and the formation of polar cap mass density anomalies. Our numerical simulation demonstrated that thermosphere dynamics readily redistributes composition, temperature, and mass through upwelling and atmospheric gravity waves. The polar cap mass density anomalies observed by the CHAMP satellite during the storm were largely a result of large-scale atmospheric gravity waves. Therefore, an increase in local thermospheric mass density does not necessarily mean there is direct energy input.

  6. Global change induced trends in ion composition of the troposphere to the lower thermosphere

    Directory of Open Access Journals (Sweden)

    G. Beig

    2008-05-01

    Full Text Available In this paper a brief overview of the changes in atmospheric ion compositions driven by the human-induced changes in related neutral species, and temperature from the troposphere to lower thermosphere has been made. It is found that ionic compositions undergo significant variations. The variations calculated for the double-CO2 scenario are both long-term and permanent in nature. Major neutrals which take part in the lower and middle atmospheric ion chemical schemes and undergo significant changes due to anthropogenic activities are: O, O2, H2O, NO, acetonitrile, pyridinated compounds, acetone and aerosol. The concentration of positive ion/electron density does not change appreciably in the middle atmosphere but indicates a marginal decrease above about 75 km until about 85 km, above which the magnitude of negative trend decreases and becomes negligible at 93 km. Acetonitrile cluster ions in the upper stratosphere are likely to increase, whereas NO+ and NO+(H2O in the mesosphere and lower thermosphere (MLT region are expected to decrease for the double CO2 scenario. It is also found that the atmospheric density of pyridinated cluster ions is fast rising in the troposphere.

  7. Scientific challenges in thermosphere-ionosphere forecasting - conclusions from the October 2014 NASA JPL community workshop

    Science.gov (United States)

    Mannucci, Anthony J.; Hagan, Maura E.; Vourlidas, Angelos; Huang, Cheryl Y.; Verkhoglyadova, Olga P.; Deng, Yue

    2016-10-01

    Interest in forecasting space weather in the thermosphere and ionosphere (T-I) led to a community workshop held at NASA's Jet Propulsion Laboratory in October, 2014. The workshop focus was "Scientific Challenges in Thermosphere-Ionosphere Forecasting" to emphasize that forecasting presumes a sufficiently advanced state of scientific knowledge, yet one that is still evolving. The purpose of the workshop, and this topical issue that arose from the workshop, was to discuss research frontiers that will lead to improved space weather forecasts. Three areas are discussed in some detail in this paper: (1) the role of lower atmosphere forcing in the response of the T-I to geomagnetic disturbances; (2) the significant deposition of energy at polar latitudes during geomagnetic disturbances; and (3) recent developments in understanding the propagation of coronal mass ejections through the heliosphere and prospects for forecasting the north-south component of the interplanetary magnetic field (IMF) using observations at the Lagrangian L5 point. We describe other research presented at the workshop that appears in the topical issue. The possibility of establishing a "positive feedback loop" where improved scientific knowledge leads to improved forecasts is described (Siscoe 2006, Space Weather, 4, S01003; Mannucci 2012, Space Weather, 10, S07003).

  8. Evidence of long term global decline in the Earth's thermospheric densities apparently related to anthropogenic effects

    Science.gov (United States)

    Keating, G. M.; Tolson, R. H.; Bradford, M. S.

    2000-05-01

    A study was performed of the long-term orbital decay of five Earth satellites with perigee altitudes averaging near 350km. To decouple long-term trend measurements from the effects of solar variability, measurements were evaluated during the years of solar minimum (1976, 1986 and 1996). Atmospheric densities derived from these essentially global measurements showed substantial evidence of a decline averaging 9.8 ± 2.5% in thermospheric density over 20 years pointing toward a long-term cooling of the upper atmosphere. Increases in greenhouse gases induced by human activity are hypothesized to warm the Earth's surface and lower atmosphere, but strongly cool the upper atmosphere. Assuming that the 10% increase in CO2 over these 20 years caused cooling resulting in the 10% decline in density, a doubling of CO2 could cause the thermospheric densities measured near 350km to decrease by a factor of 3. This decrease may shrink the altitude of a constant density surface by 40km before the end of the 21st century.

  9. Solar activity variations of nocturnal thermospheric meridional winds over Indian longitude sector

    Science.gov (United States)

    Madhav Haridas, M. K.; Manju, G.; Arunamani, T.

    2016-09-01

    The night time F-layer base height information from ionosondes located at two equatorial stations Trivandrum (TRV 8.5°N, 77°E) and Sriharikota (SHAR 13.7°N, 80.2°E) spanning over two decades are used to derive the climatology of equatorial nocturnal Thermospheric Meridional Winds (TMWs) prevailing during High Solar Activity (HSA) and Low Solar Activity (LSA) epochs. The important inferences from the analysis are 1) Increase in mean equatorward winds observed during LSA compared to HSA during pre midnight hours; 25 m/s for VE (Vernal Equinox) and 20 m/s for SS (Summer Solstice), AE (autumnal Equinox) and WS (Winter Solstice). 2) Mean wind response to Solar Flux Unit (SFU) is established quantitatively for all seasons for pre-midnight hours; rate of increase is 0.25 m/s/SFU for VE, 0.2 m/s/SFU for SS and WS and 0.08 m/s/SFU for AE. 3) Theoretical estimates of winds for the two epochs are performed and indicate the role of ion drag forcing as a major factor influencing TMWs. 4) Observed magnitude of winds and rate of flux dependencies are compared to thermospheric wind models. 5) Equinoctial asymmetry in TMWs is observed for HSA at certain times, with more equatorward winds during AE. These observations lend a potential to parameterize the wind components and effectively model the winds, catering to solar activity variations.

  10. Solar wind driving of ionosphere-thermosphere responses during three storms on St. Patrick's Day.

    Science.gov (United States)

    Verkhoglyadova, O. P.; Tsurutani, B.; Mannucci, A. J.; Komjathy, A.; Mlynczak, M. G.; Hunt, L. A.; Paxton, L. J.

    2015-12-01

    We overview solar wind features of three intense CME-driven storms occurring around the same time in March of 2012, 2013 and 2015 (74 - 80 DOY). Differences in solar wind drivers lead to different ionosphere-thermosphere (IT) responses in time, magnitude, and to different pre-conditioning. The purpose of our study is to establish a correspondence between interplanetary transient structures (parts of a CME or a high-speed-stream) and dynamics of IT parameters over the course of a geomagnetic storm. Detailed analysis will be presented for the St. Patrick's Day storm of 2015. We introduce global metrics of daytime and dusktime average ionospheric response of VTEC estimates from over ~2000 GPS ground stations distributed globally. Nitric oxide and carbon dioxide cooling radiation fluxes measured by TIMED/SABER instrument are calculated in several latitudinal bins throughout the storm phases. In addition, GUVI observations of the dynamical response of the thermosphere (NO and O/N2) are compared. SSUSI observations of the equatorial ionosphere, particularly the magnitude and separation of the equatorial arcs are considered. In our analysis, metrics are inter-compared to get better understanding of the self-consistent IT response to solar wind driving.

  11. Achievements in atmospheric science from Spacelab: The mesosphere/lower thermosphere

    Science.gov (United States)

    Torr, D. G.

    1994-01-01

    The Mesosphere and Lower Thermosphere (MLT) are adjacent regions of the upper atmosphere that cannot be easily accessed (except by rockets) by in situ measurement. For this reason, the MLT l essentially represents the last unexplored region of the planet. The advent of the shuttle and remote sensing technology over the last decade and a half have changed this situation significantly. Spacelab 1 carried the first payload of instruments capable of acquiring a comprehensive database on the MLT region, and much was learned on that mission that was subsequently used to have greatly improve the measurement capability. The ATLAS 1 payload was probably the most comprehensive ever launched to study upper atmosphere, and the mission was reported as being one of the most successful of NASA's endeavor's to date. The database acquired on ATLAS 1 will provide a reference that will be used for many years to come. It will also provide the means to gaining the first quantitative understanding of the photochemistry of the lower thermosphere and mesosphere.

  12. Observations of meso-scale neutral wind interaction with auroral precipitation in the thermosphere at EISCAT

    Science.gov (United States)

    Kosch, Michael; Nozawa, Satonori; Yiu, Ho-Ching Iris; Anderson, Callum; Ogawa, Yasunobu; Howells, Vikki; Baddeley, Lisa; Aruliah, Anasuya; McWhirter, Ian; McCrea, I. W.; Fujii, Ryoichi

    We report on observations of E-region neutral wind fields and their interaction with auroral precipitation at meso-scale spatial resolution. The EISCAT Svalbard radar was used to observe the ionospheric line-of-sight ion flows and temperatures in the E-and F-regions whilst scan-ning its beam. An all-sky optical Scanning Doppler Imager was used at 557.7 nm to observe thermospheric neutral line-of-sight winds and temperatures. High-latitude data from February 2010 are presented. In the case of an auroral arc, strong acceleration of the E-region neutral wind occurs within 10s of km to the arc on a time scale of 10s of minutes. We demonstrate through modelling that this effect cannot be explained by height changes in the 557.7 nm emis-sion layer. The most likely explanation seems to be greatly enhanced ion drag associated with the increased plasma density caused by the particle precipitation, and the localised ionospheric electric field associated with the Pedersen closure current of auroral arcs. Since Joule heat-ing occurs predominantly in the E-region, meso-scale variability in the thermosphere probably accounts for a significant under-estimation in the total energy dissipation.

  13. Tilting Saturn without Tilting Jupiter or Ejecting an Ice Giant: Constraints on migration

    Science.gov (United States)

    McNeil, Douglas S.; Lee, M. H.

    2010-10-01

    The obliquities of the giant planets preserve information about their migration and encounter histories. Are the classic Nice models (Tsiganis et al. 2005) or the resonant Nice models (Morbidelli et al. 2007) compatible with Jupiter's 3 degree tilt and Saturn's 27? Here we consider the obliquity evolution of the giants during the planetesimal-driven migration phase using two methods: (1) a purely secular integration of the Laplace-Lagrange equations with spin, and (2) a hybrid N-body scheme with full interactions between the Sun and the giants but imposed prescriptions for migration and eccentricity and inclination damping. We find that it is difficult to reproduce today's obliquity values as migration timescales sufficient to tilt Saturn via the Hamilton & Ward (2004) secular spin-orbit resonance mechanism generally suffice to tilt Jupiter more than is observed. Moreover, long migration timescales which make tilting Saturn easier simultaneously reduce the survival fraction (to below 20% for timescales longer than 20 Myr.) We discuss the constraints these observations provide on the dynamical history of the giant planets, and the remaining possibility of tilting Saturn during a late very slow migration of Neptune to its present location after the main phase of migration is complete. [This work was supported by Hong Kong RGC grant HKU 7024/08P.

  14. A spin-orbit alignment for the hot Jupiter HATS-3b

    Energy Technology Data Exchange (ETDEWEB)

    Addison, B. C.; Tinney, C. G.; Wright, D. J. [Exoplanetary Science Group, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Bayliss, D., E-mail: b.addison@unsw.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia)

    2014-09-10

    We have measured the alignment between the orbit of HATS-3b (a recently discovered, slightly inflated Hot Jupiter) and the spin axis of its host star. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The sky-projected spin-orbit angle of λ = 3° ± 25° was determined from spectroscopic measurements of the Rossiter-McLaughlin effect. This is the first exoplanet discovered through the HATSouth transit survey to have its spin-orbit angle measured. Our results indicate that the orbital plane of HATS-3b is consistent with being aligned to the spin axis of its host star. The low obliquity of the HATS-3 system, which has a relatively hot mid F-type host star, agrees with the general trend observed for Hot Jupiter host stars with effective temperatures >6250 K to have randomly distributed spin-orbit angles.

  15. Features of Hypothetical Plasma Phase Transition in Interiors of Saturn and Jupiter

    CERN Document Server

    Ukrainets, Artem

    2013-01-01

    Anomalous features for hypothetical Plasma Phase Transitions (PPT), which is expected to occur in mixed hydrogen-helium plasma in interior of Jupiter and Saturn, are under discussion. The characteristics of the Coulomb and density corrections (the so-called non-ideality corrections) are reconstructed for hydrogen-helium plasma in the vicinity of phase coexistence boundary of this PPT in version of Saumon and Chabrier, using tabular data for hydrogen-helium EOS of Saumon, Chabrier and VanHorn and some general thermodynamic relations. Two previously unknown characteristics of the studied PPT have been estimated based on these results: (i) -- the jump of the electrostatic potential across the phase boundary of PPT (Galvani potential), and (ii) -- the scale of non-congruency for this PPT (the differences in chemical composition of the coexisting hydrogen-helium phases), which could be expected in H2/He mixture at typical parameters of plasma in interior of Jupiter and Saturn. While the first effect -- the potenti...

  16. Molecular formation along the atmospheric mass loss of HD 209458 b and similar Hot Jupiters

    CERN Document Server

    Pinotti, Rafael

    2016-01-01

    The chemistry along the mass loss of Hot Jupiters is generally considered to be simple, consisting mainly of atoms, prevented from forming more complex species by the intense radiation field from their host stars. In order to probe the region where the temperature is low (T < 2000 K), we developed a 1D chemical and photochemical reaction model of the atmospheric mass loss of HD 209458 b, involving 56 species, including carbon chain and oxygen bearing ones, interacting through 566 reactions. The simulation results indicate that simple molecules like OH+, H2O+ and H3O+ are formed inside the region, considering that residual H2 survives in the exosphere, a possibility indicated by recent observational work. The molecules are formed and destroyed within a radial distance of less than 10^7 km, but the estimated integrated column density of OH+, a potential tracer of H2, is high enough to allow detection, which, once achieved, would indicate a revision of chemical models of the upper atmosphere of Hot Jupiters. ...

  17. Thermospheric mass density variations during geomagnetic storms and a prediction model based on the merging electric field

    NARCIS (Netherlands)

    Liu, R.; Lühr, H.; Doornbos, E.; Ma, S.Y.

    2010-01-01

    With the help of four years (2002–2005) of CHAMP accelerometer data we have investigated the dependence of low and mid latitude thermospheric density on the merging electric field, Em, during major magnetic storms. Altogether 30 intensive storm events (Dstmin <−100 nT) are chosen for a statistical s

  18. ISO celebrates its prolonged life with a video of Jupiter

    Science.gov (United States)

    1997-07-01

    This is excellent news for astronomers and especially for the multinational teams, with leaders in France, Germany, the Netherlands and the United Kingdom, who spent many years devising the four instruments served by ISO's telescope. The camera ISOCAM, the photometer ISOPHOT, the Short Wavelength Spectrometer and the Long Wavelength Spectrometer span between them an unprecedented range of infrared wavelengths from 2 to 200 microns. The atmosphere of Jupiter is one of the cool and cloudy places attracting ISO's attention, and ESA today releases a video of unprecedented images of Jupiter. The planet changes its appearance drastically as the camera ISOCAM scans a range of 90 different infrared wavelengths. Picture by picture, ISOCAM picks out different features of the atmosphere's composition and behaviour. These and other results from ISO will enable scientists to sharpen their ideas about how Jupiter's weather works. "ISO is giving us a new impression of the giant planets of the Solar System," comments Roger Bonnet, ESA's director of science. "Not just Jupiter, but Saturn, Uranus and Neptune too. By observing the planets across its very wide range of infrared wavelengths, ISO can see features overlooked even by spacecraft visiting the planets. The remarkable movie of Jupiter released today represents only a few per cent of ISO's wavelength range, yet every image tells its own story." More information about the Jupiter video appears later in this Information Note. How ISO's cold telescope beat the calendar The need to keep ISO's telescope and instruments chilled to a very low temperature sets a limit to their useful operating life. ISO was supplied with more than 2000 litres of superfluid helium to cool it. Slow evaporation maintains key parts of the spacecraft at temperatures close to absolute zero, below minus 271 degrees C. The rate of loss of helium was expected to be about 3 litres a day, but the cryogenic system could not be tested in exactly the conditions

  19. Secular dynamics of multiplanet systems: implications for the formation of hot and warm Jupiters via high-eccentricity migration

    Science.gov (United States)

    Hamers, Adrian S.; Antonini, Fabio; Lithwick, Yoram; Perets, Hagai B.; Portegies Zwart, Simon F.

    2017-01-01

    Hot Jupiters (HJs) are Jupiter-like planets that reside very closely to their host star, within ˜0.1 au. Their formation is not well understood. It is generally believed that they cannot have formed in situ, implying that some form of migration must have occurred after their initial formation. We study the production of HJs through secular evolution in multiplanet systems with three to five planets. In this variant of high-e migration, the eccentricity of the orbit of the innermost planet is excited on secular time-scales, triggering orbital migration due to tidal dissipation. We use a secular dynamics code and carry out a population synthesis study. We find that HJs are only produced if the viscous time-scale is short (≈0.014 yr). In contrast, in up to ≈0.3 of systems, the innermost planet is tidally disrupted. The orbital period distribution is peaked around 5 d, consistent with observations. The median HJ mass is 1 MJ with a maximum of ≈2 MJ, similar to observed HJs. Approximately 0.1 of the HJs have retrograde orbits with respect to the stellar spin. We do not find a significant population of warm Jupiters in our simulations, i.e. planets with semimajor axes between 0.1 and 1 au.

  20. Zonal Flow and Vortices in Anelastic Deep Convection Models of Jupiter and Saturn With Shallow Stable Stratification

    Science.gov (United States)

    Heimpel, M. H.; Wicht, J.; Gastine, T.

    2015-12-01

    Planetary jet streams and vortices have been studied for over 350 years, yet their origin and dynamics are still vigorously debated. On both Jupiter and Saturn zonal flow consists of equatorial superrotation and alternating East-West jets at higher latitude. On Jupiter, numerous vortices, the vast majority anticyclones, occur with various sizes and lifetimes, interacting strongly with the zonal flow. Saturn's vortices and jets are also clearly coupled, and its North and South polar vortices are cyclonic. Models of giant planet atmospheres have generally been of two classes. Shallow flow models produce jets and vortices from 2D turbulence in a very thin spherical layer, but require special conditions to reproduce observed equatorial superrotation. In contrast, deep convection models generically reproduce equatorial superrotation, but typically lack coherent vortices, which do not survive the formation of jets. Here, we combine elements of both approaches using a 3D spherical shell compressible fluid numerical model, driven by convection at depth, but grading to a stably stratified shallow layer. In typical model simulations convective plumes rising from the deep interior impinge on the stably stratified layer, diverge near the outer spherical surface, and efficiently create the dominant anticyclones, which are shielded by downwelling cyclonic rings and filaments. These results may explain the dominance of anticyclones and the flow structure of small and medium sized anticyclonic ovals on Jupiter. The largest of our model vortices form in westward anticyclonic shear nearest the equatorial jet, similar to Saturn's "storm alley" and Jupiter's Great Red Spot. We also explore conditions under which cyclones, including polar cyclones like those on Saturn, may form.

  1. Evolution of Jupiter's auroral-related stratospheric heating and chemistry

    Science.gov (United States)

    Sinclair, James; Orton, Glenn S.; Greathouse, Thomas K.; Fletcher, Leigh N.; Moses, Julianne I.; Hue, Vincent; Irwin, Patrick Gerard Joseph; Melin, Henrik; Giles, Rohini Sara

    2016-10-01

    Auroral processes on Jupiter are evident over a large range of wavelengths. Emission at X-ray, UV and near-infrared wavelengths highlights the precipitation of charged particles in Jupiter's ionosphere. Jupiter's auroral regions also exhibit enhanced mid-infrared emission of CH4 (7.8-μm), C2H2 (13-μm), C2H4 (10.5-μm) and C2H6 (12.2-μm), which indicates auroral processes modify the thermal structure and chemistry of the neutral stratosphere at pressures from 10 mbar to 10 μbar. In Sinclair et al., 2016a (submitted), 2016b (in preparation), we investigated these processes further by performing a retrieval analysis of Voyager-IRIS (Infrared Interferometer Spectrometer) observations measured in November 1979, Cassini-CIRS (Composite Infrared Spectrometer) observations measured in January 2001 and IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph on NASA's Infrared Telescope Facility) spectra measured in December 2014. These datasets however captured Jupiter at significantly different epochs and thus the overall global evolution of atmospheric conditions as well as differences in spatial sampling, spectral resolution (and therefore vertical resolution in the atmosphere) have made inferences of the temporal evolution in auroral regions a challenge. However, in April 2016, we acquired IRTF-TEXES observations of Jupiter's high latitudes, using observing parameters very similar to those in December 2014. By performing a similar analysis of these observations and comparing results between December 2014 and April 2016, we can investigate the evolution of the thermal structure and chemistry in Jupiter's auroral regions over a 15 month timescale. The magnitude of temperature/composition changes and the altitudes at which they occur will provide insights into how auroral processes in the ionosphere propagate to the stratosphere. In particular, we can assess whether the evolution of stratospheric conditions in auroral regions is related to the decrease in solar activity

  2. Short Time-Scale Enhancements to the Global Thermosphere Temperature and Nitric Oxide Content Resulting From Ionospheric Joule Heating

    Science.gov (United States)

    Weimer, D. R.; Mlynczak, M. G.; Hunt, L. A.; Sutton, E. K.

    2014-12-01

    The total Joule heating in the polar ionosphere can be derived from an empirical model of the electric fields and currents, using input measurements of the solar wind velocity and interplanetary magnetic field (IMF). In the thermosphere, measurements of the neutral density from accelerometers on the CHAMP and GRACE satellites are used to derive exospheric temperatures, showing that enhanced ionospheric energy dissipation produces elevated temperatures with little delay.Using the total ionospheric heating, changes in the global mean exosphere temperature as a function of time can be calculated with a simple differential equation. The results compare very well with the CHAMP and GRACE measurement. A critical part of the calculation is the rate at which the thermosphere cools after the ionospheric heating is reduced. It had been noted previously that events with significant levels of heating subsequently cool at a faster rate, and this cooling was attributed to enhanced nitric oxide emissions. This correlation with nitric oxide has been confirmed with very high correlations with measurements of nitric oxide emissions in the thermosphere, from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. These measurements were used in a recent improvement in the equations that calculate the thermosphere temperature. The global nitric oxide cooling rates are included in this calculation, and the predicted levels of nitric oxide, derived from the ionosphere heating model, match the SABER measurements very well, having correlation coefficients on the order of 0.9.These calculations are used to govern the sorting of measurements CHAMP and GRACE measurements, on the basis of the global temperature enhancements due to Joule heating, as well as various solar indices, and season. Global maps of the exospheric temperature are produced from these sorted data.

  3. Jupiter's Phase Variations from Cassini: a testbed for future direct-imaging missions

    CERN Document Server

    Mayorga, L C; Rages, K; West, R A; Knowles, B; Lewis, N; Marley, M S

    2016-01-01

    We present phase curves of Jupiter from 0-140 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. Phase curves are of interest for studying the energy balance of Jupiter and understanding the scattering behavior of Jupiter as an exoplanet analog. We find that Jupiter is significantly darker at partial phases than an idealized Lambertian planet by roughly 25% and is not well fit by Jupiter-like exoplanet atmospheric models across all wavelengths. We provide analytic fits to Jupiter's phase function in several Cassini/ISS imaging filter bandpasses. In addition, these observations show that Jupiter's color is more variable with phase angle than predicted by models. Therefore, the color of even a near Jupiter-twin planet observed at a partial phase cannot be assumed to be comparable to that of Jupiter at full phase. We discuss how WFIRST and other future direct-imaging missions can enhance the study of cool giants.

  4. 3-Dimensional numerical simulations of the dynamics of the Venusian mesosphere and thermosphere

    Science.gov (United States)

    Tingle, S.; Mueller-Wodarg, I. C.

    2009-12-01

    We present the first results from a new 3-dimensional numerical simulation of the steady state dynamics of the Venusian mesosphere and thermosphere (60-300 km). We have adapted the dynamical core of the Titan thermosphere global circulation model (GCM) [1] to a steady state background atmosphere. Our background atmosphere is derived from a hydrostatic combination of the VTS3 [2] and Venus International Reference Atmosphere (VIRA) [3] empirical models, which are otherwise discontinuous at their 100 km interface. We use 4th order polynomials to link the VTS3 and VIRA thermal profiles and employ hydrostatic balance to derive a consistent density profile. We also present comparisons of our background atmosphere to data from the ESA Venus Express Mission. The thermal structure of the Venusian mesosphere is relatively well documented; however, direct measurements of wind speeds are limited. Venus’ slow rotation results in a negligible Coriolis force. This suggests that the zonal circulation should arise from cyclostrophic balance; where the equatorward component of the centrifugal force balances poleward meridional pressure gradients [4]. The sparseness of direct and in-situ measurements has resulted in the application of cyclostrophic balance to measured thermal profiles to derive wind speeds [5] [6] [7] [8]. However, cyclostrophic balance is only strictly valid at mid latitudes (˜ ± 30-75°) and its applicability to the Venusian mesosphere has not been conclusively demonstrated. Our simulations, by solving the full Navier-Stokes momentum equation, will enable us assess the validity of cyclostrophic balance as a description of mesospheric dynamics. This work is part of an ongoing project to develop the first GCM to encompass the atmosphere from the cloud tops into the thermosphere. When complete, this model will enable self-consistent calculations of the dynamics, energy and composition of the atmosphere. It will thus provide a framework to address many of the

  5. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

    Energy Technology Data Exchange (ETDEWEB)

    Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

    2007-11-08

    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  6. Mechanisms affecting the composition of Hot Jupiters atmospheres

    Directory of Open Access Journals (Sweden)

    Showman Adam P.

    2013-04-01

    Full Text Available Opacities and thus local chemical composition play a key role when characterizing exoplanet atmospheres from observations. When the gas is in chemical equilibrium the chemical abundances depend strongly on the temperature profile. Grey models tend to overestimate the temperatures in the upper atmosphere. We present a new analytical model with a more realistic description of the radiative cooling in the infrared. Mechanisms like quenching and cold traps can drive the upper atmosphere far from its chemical equilibrium. The efficiency of these mechanisms depends on the strength of the vertical mixing. Using 3D global circulation models of HD209458b including passive tracers, we show that, although Hot Jupiter atmospheres are stably stratified, they are strongly mixed by planetary scale circulation patterns. We provide a rough estimate of the effective vertical mixing coefficient in Hot Jupiter atmosphere which can be used in 1D models.

  7. Doppler Signatures of the Atmospheric Circulation on Hot Jupiters

    CERN Document Server

    Showman, Adam P; Lewis, Nikole K; Shabram, Megan

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation--and Doppler signature--of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blue- and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps...

  8. Ongoing Analysis of Jupiter's Equatorial Hotspots and Plumes from Cassini

    Science.gov (United States)

    Choi, D. S.; Showmwn, A. P.; Vasavada, A. R.; Simon-Miller, A. A.

    2012-01-01

    We present updated results from our ongoing analysis of Cassini observations of Jupiter's equatorial meteorology. For two months preceding the spacecraft's closest approach of the planet, the ISS instrument onboard Cassini regularly imaged the atmosphere of Jupiter. We created time-lapse movies from this period that show the complex activity and interactions of the equatorial atmosphere. During this period, hot spots exhibited significant variations in size and shape over timescales of days and weeks. Some of these changes appear to be a result of interactions with passing vortex systems in adjacent latitudes. Strong anticyclonic gyres to the southeast of the dark areas converge with flow from the west and appear to circulate into a hot spot at its southwestern corner.

  9. Tidal Dissipation and Obliquity Evolution in Hot Jupiter Systems

    CERN Document Server

    Valsecchi, Francesca

    2014-01-01

    Two formation scenarios have been proposed to explain the tight orbits of hot Jupiters. These giant planets could be formed in low-obliquity orbits via disk migration or in high-obliquity orbits via high-eccentricity migration, where gravitational interactions with a companion are at play, together with tidal dissipation. Here we target the observed misaligned hot Jupiter systems to investigate whether their current properties are consistent with high-eccentricity migration. Specifically, we study whether tidal dissipation in the star can be responsible for the observed distribution of misalignments and orbital separations. Improving on previous studies, we use detailed models for the stellar component, thus accounting for how convection (and thus tidal dissipation) depends on the host star properties. We find that the currently observed degree of misalignment increases as the amount of surface convection in the host star decreases. This trend supports the hypothesis that tides are the mechanism shaping the o...

  10. The STARE Project A Transit Search for Hot Jupiters

    CERN Document Server

    Brown, T M; Brown, Timothy M.; Charbonneau, David

    2000-01-01

    The STARE instrument is a small aperture, wide-field, CCD-based telescope that delivers high cadence time series photometry on roughly 40,000 stars in a typical field centered on the galactic plane. In a two-month observing run on a field, we obtain sufficient precision on roughly 4,000 stars to detect a close-in Jupiter-sized companion in an edge-on orbit. We also used this instrument to detect the planetary transits across the Sun-like star HD209458. The project is now in its third season, and we have acquired a large dataset on several fields. Given the frequency of close-in extrasolar planets found by the radial velocity surveys, and the recent confirmation that at least some of these are indeed gas giants, the STARE project should be able to detect roughly a dozen Jupiter-sized planets in its existing dataset.

  11. Telecommunications Antennas for the Juno Mission to Jupiter

    Science.gov (United States)

    Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.

    2012-01-01

    The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.

  12. Where is the main source of Jupiter family comets situated?

    CERN Document Server

    Kazantsev, A M

    2012-01-01

    An attempt to determine spatial location of the main source of short-period comet nuclei was made. There were carried out numerical calculations for orbit evolution of Jupiter family comets, comets with middle-period orbits and bodies of Centaur group. On the basis of the calculations it was shown, that orbital evolution of the solar system small bodies is mainly going in the direction of the semi-major axes increase. It belongs to the bodies which can undergo approaches the planets, and orbital evolution of which is mainly going due to the gravitational forces. Such result is confirmed by qualitative analysis of changes of small body semi-major axes under approaches the planets. The conclusion was drawn that the main source of nuclei of Jupiter family comets is apparently situated at distances from the Sun not more than 6 AU.

  13. Solar wind collimation of the Jupiter high velocity dust streams

    Science.gov (United States)

    Flandes, A.; Krueger, H.

    2006-12-01

    The dust bursts discovered by the Ulysses dust sensor when approaching Jupiter in 1992 were later confirmed as collimated streams of high velocity (~200 km/s) charged (~5V) dust grains escaping from Jupiter and dominated by the interplanetary Magnetic field (IMF). With Cassini, a similar phenomenon was observed in Saturn. It was demonstrated that the Jovian dust streams are closely related to the solar wind compressed regions, either Corotating interaction regions (CIRs) or Coronal mass ejections (CMEs) ¨Cto a minor extent-. Actually the dust streams seem ultimately to be generated by such events. This can be explained considering that dust grains are accelerated as they gain substantial energy while compressed at the forward and reverse shocks that bound or precede these solar wind regions.

  14. Transmission spectral properties of clouds for hot Jupiter exoplanets

    CERN Document Server

    Wakeford, Hannah R

    2014-01-01

    Clouds have an important role in the atmospheres of planetary bodies. It is expected that, like all the planetary bodies in our solar system, exoplanet atmospheres will also have substantial cloud coverage, and evidence is mounting for clouds in a number of hot Jupiters. In order to better characterise planetary atmospheres we need to consider the effects these clouds will have on the observed broadband transmission spectra. Here we examine the expected cloud condensate species for hot Jupiter exoplanets and the effects of various grain sizes and distributions on the resultant transmission spectra from the optical to infrared, which can be used as a broad framework when interpreting exoplanet spectra. We note that significant infrared absorption features appear in the computed transmission spectrum, the result of vibrational modes between the key species in each condensate, which can potentially be very constraining. While it may be hard to differentiate between individual condensates in the broad transmissio...

  15. Telecommunications Antennas for the Juno Mission to Jupiter

    Science.gov (United States)

    Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.

    2012-01-01

    The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.

  16. Detection of an oxygen atmosphere on Jupiter's moon Europa.

    Science.gov (United States)

    Hall, D T; Strobel, D F; Feldman, P D; McGrath, M A; Weaver, H A

    1995-02-23

    Europa, the second large satellite out from Jupiter, is roughly the size of Earth's Moon, but unlike the Moon, it has water ice on its surface. There have been suggestions that an oxygen atmosphere should accumulate around such a body, through reactions which break up the water molecules and form molecular hydrogen and oxygen. The lighter H2 molecules would escape from Europa relatively easily, leaving behind an atmosphere rich in oxygen. Here we report the detection of atomic oxygen emission from Europa, which we interpret as being produced by the simultaneous dissociation and excitation of atmospheric O2 by electrons from Jupiter's magnetosphere. Europa's molecular oxygen atmosphere is very tenuous, with a surface pressure about 10(-11) that of the Earth's atmosphere at sea level.

  17. Secular Chaos and the Production of Hot Jupiters

    CERN Document Server

    Wu, Yanqin

    2010-01-01

    In a planetary system with two or more well-spaced, eccentric, inclined planets, secular interactions may lead to chaos. The innermost planet may gradually become very eccentric and/or inclined, as a result of the secular degrees of freedom drifting towards equipartition of angular momentum deficit. Secular chaos is known to be responsible for the eventual destabilization of Mercury in our own Solar System. Here we focus on systems with three giant planets. We characterize the secular chaos and demonstrate the criterion for it to occur, but leave a detailed understanding of secular chaos to a companion paper (Lithwick & Wu, 2010). After an extended period of eccentricity diffusion, the inner planet's pericentre can approach the star to within a few stellar radii. Strong tidal interactions and ensuing tidal dissipation extracts orbital energy from the planet and pulls it inward, creating a hot Jupiter. In contrast to other proposed channels for the production of hot Jupiters, such a scenario (which we term...

  18. Dust en-route to Jupiter and the Galilean satellites

    CERN Document Server

    Krüger, H; Krueger, Harald; Gruen, Eberhard

    2002-01-01

    Spacecraft investigations during the last ten years have vastly improved our knowledge about dust in the Jovian system. All Galilean satellites, and probably all smaller satellites as well, are sources of dust in the Jovian system. In-situ measurements with the dust detectors on board the Ulysses and Galileo spacecraft have for the first time demonstrated the electromagnetic interaction of charged dust grains with the interplanetary magnetic field and with a planetary magnetosphere. Jupiter's magnetosphere acts as a giant mass-velocity spectrometer for charged 10-nanometer dust grains. These dust grains are released from Jupiter's moon Io with typical rate of 1 kg s^1. The dust streams probe the plasma conditions in the Io plasma torus and can be used as a potential monitor of Io's volcanic plume activity. The other Galilean satellites are surrounded by tenuous impact-generated clouds of mostly sub-micrometer ejecta grains. Galileo measurements have demonstrated that impact-ejecta derived from hypervelocity i...

  19. ATMOSPHERIC CIRCULATION OF HOT JUPITERS: DAYSIDE–NIGHTSIDE TEMPERATURE DIFFERENCES

    Energy Technology Data Exchange (ETDEWEB)

    Komacek, Thaddeus D.; Showman, Adam P., E-mail: tkomacek@lpl.arizona.edu [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States)

    2016-04-10

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing dayside-to-nightside brightness temperature difference with increasing equilibrium temperature. Here, we present a three-dimensional model that explains this relationship, in order to provide insight into the processes that control heat redistribution in tidally locked planetary atmospheres. This three-dimensional model combines predictive analytic theory for the atmospheric circulation and dayside–nightside temperature differences over a range of equilibrium temperatures, atmospheric compositions, and potential frictional drag strengths with numerical solutions of the circulation that verify this analytic theory. The theory shows that the longitudinal propagation of waves mediates dayside–nightside temperature differences in hot Jupiter atmospheres, analogous to the wave adjustment mechanism that regulates the thermal structure in Earth’s tropics. These waves can be damped in hot Jupiter atmospheres by either radiative cooling or potential frictional drag. This frictional drag would likely be caused by Lorentz forces in a partially ionized atmosphere threaded by a background magnetic field, and would increase in strength with increasing temperature. Additionally, the amplitude of radiative heating and cooling increases with increasing temperature, and hence both radiative heating/cooling and frictional drag damp waves more efficiently with increasing equilibrium temperature. Radiative heating and cooling play the largest role in controlling dayside–nightside temperature differences in both our analytic theory and numerical simulations, with frictional drag only being important if it is stronger than the Coriolis force. As a result, dayside–nightside temperature differences in hot Jupiter atmospheres increase with increasing stellar irradiation and decrease with increasing pressure.

  20. The New Horizons Mission to Pluto and Flyby of Jupiter

    Science.gov (United States)

    Stern, Alan; Weaver, Hal; Young, Leslie; Bagenal, Fran; Binzel, Richard; Buratti, Bonnie; Cheng, andy; Cruikshank, Dale; Gladstone, Randy; Grundy, Will; Hinson, David; Horanyi, Mihaly; Jennings, Don; Linscott, Ivan; McComas, Dave; McKinnon, William; McNutt, Ralph; Moore, Jeffrey; Murchie, Scott; Olkin, Cathy; Porco, Carolyn; Reitsema, Harold; Reuter, Dennis; Slater, Dave; Spencer, John

    2008-01-01

    New Horizons (NH) is NASA's mission to provide the first in situ reconnaissance of Pluto and its moons Charon, Nix, and Hydra. The NH spacecraft will reach Pluto in July 2015 and will then, if approved for an extended mission phase, continue on to a flyby encounter with one or more Kuiper belt objects (KBOs). NH was launched on 19 January 2006 and received a gravity assist during a flyby encounter with Jupiter (with closest approach at -32 RJ on 28 February 2007) that reduced its flight time to Pluto by 3 years. During the Jupiter flyby, NH collected a trove of multi-wavelength imaging and fields-and-particles measurements. Among the many science results at Jupiter were a detection of planet-wide mesoscale waves, eruptions of atmospheric ammonia clouds, unprecedented views of Io's volcanic plumes and Jupiter's tenuous ring system, a first close-up of the Little Red Spot (LRS), first sightings of polar lightning, and a trip down the tail of the magnetosphere. In 2015, NH will conduct a seven-month investigation of the Pluto system culminating in a closest approach some 12,500 km from Pluto's surface. Planning is presently underway for the Pluto encounter with special emphasis on longidentified science goals of studying the terrain, geology, and composition of the surfaces of Pluto and Charon, examining the composition and structure of Pluto's atmosphere, searching for an atmosphere on Charon, and characterizing Pluto's ionosphere and solar wind interaction. Detailed inspections will also be performed of the newly discovered satellites Nix and Hydra. Additionally, NH will characterize energetic particles in Pluto's environment, refine the bulk properties of Pluto and Charon, and search for additional satellites and rings.