WorldWideScience

Sample records for transiting planetary systems

  1. Transiting planetary system WASP-17 (Southworth+, 2012)

    DEFF Research Database (Denmark)

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

    2013-01-01

    A light curve of four transits of the extrasolar planetary system WASP-17 is presented. The data were obtained using the Danish 1.5m telescope and DFOSC camera at ESO La Silla in 2012, with substantial telescope defocussing in order to improve the photometric precision of the observations...

  2. High-precision photometry by telescope defocusing - I. The transiting planetary system WASP-5

    DEFF Research Database (Denmark)

    Southworth, J.; Hinse, T. C.; Jørgensen, U. G.

    2009-01-01

    We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to minimize both random and flat-fielding errors, we defocused the telescope so its point spread...

  3. PHYSICAL PROPERTIES OF THE 0.94-DAY PERIOD TRANSITING PLANETARY SYSTEM WASP-18

    International Nuclear Information System (INIS)

    Southworth, John; Anderson, D. R.; Maxted, P. F. L.; Hinse, T. C.; Dominik, M.; Mathiasen, M.; Browne, P.; Glitrup, M.; Joergensen, U. G.; Harpsoee, K.; Liebig, C.; Maier, G.; Bozza, V.; Calchi Novati, S.; Mancini, L.; Burgdorf, M.; Dreizler, S.; Hessman, F.; Hundertmark, M.; Finet, F.

    2009-01-01

    We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocusing we achieve a photometric precision of 0.47-0.83 mmag per observation over complete transit events. The data are analyzed using the JKTEBOP code and three different sets of stellar evolutionary models. We find the mass and radius of the planet to be M b = 10.43 ± 0.30 ± 0.24 M Jup and R b = 1.165 ± 0.055 ± 0.014 R Jup (statistical and systematic errors), respectively. The systematic errors in the orbital separation and the stellar and planetary masses, arising from the use of theoretical predictions, are of a similar size to the statistical errors and set a limit on our understanding of the WASP-18 system. We point out that seven of the nine known massive transiting planets (M b > 3 M Jup ) have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less-massive planets. This may indicate that there are two different populations of transiting planets, but could also be explained by observational biases. Further radial velocity observations of low-mass planets will make it possible to choose between these two scenarios.

  4. Planetary Data System (PDS)

    Data.gov (United States)

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

  5. Three Transits for the Price of One: Super-Earth Transits of the Nearest Planetary System Discovered By Kepler/K2

    Science.gov (United States)

    Redfield, Seth; Niraula, Prajwal; Hedges, Christina; Crossfield, Ian; Kreidberg, Laura; Greene, Tom; Rodriguez, Joey; Vanderburg, Andrew; Laughlin, Gregory; Millholland, Sarah; Wang, Songhu; Cochran, William; Livingston, John; Gandolfi, Davide; Guenther, Eike; Fridlund, Malcolm; Korth, Judith

    2018-05-01

    We propose primary transit observations of three Super-Earth planets in the newly discovered planetary system around a bright, nearby star, GJ 9827. We recently announced the detection of three super-Earth planets in 1:3:5 commensurability, the inner planet, GJ 9827 b having a period of 1.2 days. This is the nearest planetary system that Kepler or K2 has found, at 30 pc, and given its brightness is one of the top systems for follow-up characterization. This system presents a unique opportunity to acquire three planetary transits for the price of one. There are several opportunities in the Spitzer visibility windows to obtain all three transits in a short period of time. We propose 3.6 micron observations of all three Super-Earth transits in a single 18-hour observation window. The proximity to a 1:3:5 resonance is intriguing from a dynamical standpoint as well. Indeed, anomalous transit timing offsets have been measured for planet d in Hubble observations that suffer from partial phase coverage. The short cadence and extended coverage of Spitzer is essential to provide a firm determination of the ephemerides and characterize any transit timing variations. Constraining these orbital parameters is critical for follow-up observations from space and ground-based telescopes. Due to the brightness of the host star, this planetary system is likely to be extensively observed in the years to come. Indeed, our team has acquired observations of the planets orbiting GJ9827 with Hubble in the ultraviolet and infrared. The proposed observations will provide infrared atmospheric measurements and firm orbital characterization which is critical for planning and designing future observations, in particular atmospheric characterization with JWST.

  6. Investigating Extra-solar Planetary System Qatar-1 through Transit Observations

    Science.gov (United States)

    Thakur, Parijat; Mannaday, Vineet Kumar; Jiang, Ing-Guey; Sahu, Devendra Kumar; Chand, Swadesh

    2018-04-01

    We report the results of the transit timing variation (TTV) analysis of the extra-solar planet Qatar-1b using thirty eight light curves. Our analysis combines thirty five previously available transit light curves with three new transits observed by us between June 2016 and September 2016 using the 2-m Himalayan Chandra Telescope (HCT) at the Indian Astronomical Observatory (Hanle, India). From these transit data, the physical and orbital parameters of the Qatar-1 system are determined. In addition to this, the ephemeris for the orbital period and mid-transit time are refined to investigate the possible TTV. We find that the null-TTV model provides the better fit to the (O-C) data. This indicates that there is no evidence for TTVs to confirm the presence of additional planets in the Qatar-1 system. The use of the 3.6-m Devasthal Optical Telescope (DOT) operated by the Aryabhatta Research Institute of Observational Sciences (ARIES, Nainital, India) could improve the photometric precision to examine the signature of TTVs in this system with a greater accuracy than in the present work.

  7. MODEL-INDEPENDENT STELLAR AND PLANETARY MASSES FROM MULTI-TRANSITING EXOPLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Montet, Benjamin T.; Johnson, John Asher

    2013-01-01

    Precise exoplanet characterization requires precise classification of exoplanet host stars. The masses of host stars are commonly estimated by comparing their spectra to those predicted by stellar evolution models. However, spectroscopically determined properties are difficult to measure accurately for stars that are substantially different from the Sun, such as M-dwarfs and evolved stars. Here, we propose a new method to dynamically measure the masses of transiting planets near mean-motion resonances and their host stars by combining observations of transit timing variations with radial velocity (RV) measurements. We derive expressions to analytically determine the mass of each member of the system and demonstrate the technique on the Kepler-18 system. We compare these analytic results to numerical simulations and find that the two are consistent. We identify eight systems for which our technique could be applied if follow-up RV measurements are collected. We conclude that this analysis would be optimal for systems discovered by next-generation missions similar to TESS or PLATO, which will target bright stars that are amenable to efficient RV follow-up.

  8. Two planetary systems with transiting Earth-size and super-Earth planets orbiting late-type dwarf stars

    Science.gov (United States)

    Alonso, E. Díez; Hernández, J. I. González; Suárez Gómez, S. L.; Aguado, D. S.; González Gutiérrez, C.; Suárez Mascareño, A.; Cabrera-Lavers, A.; González-Nuevo, J.; Toledo-Padrón, B.; Gracia, J.; de Cos Juez, F. J.; Rebolo, R.

    2018-06-01

    We present two new planetary systems found around cool dwarf stars with data from the K2 mission. The first system was found in K2-XX1 (EPIC 248545986), characterized in this work as M3.0V and observed in the 14th campaign of K2. It consists of three Earth-size transiting planets with radii of 1.1, 1.0 and 1.1 R⊕, showing a compact configuration with orbital periods of 5.24, 7.78 and 10.1 days, close to 2:3:4 resonance. The second was found in K2-XX2 (EPIC 249801827), characterized in this work as M0.5V and observed in the 15th campaign. It consists of two transiting super-Earths with radii 2.0 and 1.8 R⊕ and orbital periods of 6.03 and 20.5 days. The equilibrium temperatures of the atmospheres of these planets are estimated to be in the range of 380-600 K and the amplitudes of signals in transmission spectroscopy are estimated at ˜ 10 ppm.

  9. CHARACTERIZATION OF THE K2-19 MULTIPLE-TRANSITING PLANETARY SYSTEM VIA HIGH-DISPERSION SPECTROSCOPY, AO IMAGING, AND TRANSIT TIMING VARIATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Narita, Norio; Hori, Yasunori; Kusakabe, Nobuhiko; Takeda, Yoichi; Tamura, Motohide [Astrobiology Center, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Hirano, Teruyuki [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Fukui, Akihiko; Yanagisawa, Kenshi [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Sanchis-Ojeda, Roberto [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Winn, Joshua N. [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ryu, Tsuguru; Onitsuka, Masahiro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Kudo, Tomoyuki [Subaru Telescope, 650 North A’ohoku Place, Hilo, HI 96720 (United States); Delrez, Laetitia; Gillon, Michael; Jehin, Emmanuel [Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Bat. B5C, B-4000 Liège (Belgium); McCormac, James [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Holman, Matthew [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Izumiura, Hideyuki, E-mail: norio.narita@nao.ac.jp [SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2015-12-10

    K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ∼7 R{sub ⊕} (inner planet b) and ∼4 R{sub ⊕} (outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2 m telescope. We find that the host star is a relatively old (≥8 Gyr) late G-type star (T{sub eff} ∼ 5350 K, M{sub s} ∼ 0.9 M{sub ⊙}, and R{sub s} ∼ 0.9 R{sub ⊙}). We do not find any contaminating faint objects near the host star that could be responsible for (or dilute) the transit signals. We have also conducted transit follow-up photometry for the inner planet with KeplerCam on the FLWO 1.2 m telescope, TRAPPISTCAM on the TRAPPIST 0.6 m telescope, and MuSCAT on the OAO 1.88 m telescope. We confirm the presence of transit timing variations (TTVs), as previously reported by Armstrong and coworkers. We model the observed TTVs of the inner planet using the synodic chopping formulae given by Deck and Agol. We find two statistically indistinguishable solutions for which the period ratios (P{sub c}/P{sub b}) are located slightly above and below the exact 3:2 commensurability. Despite the degeneracy, we derive the orbital period of the inner planet P{sub b} ∼ 7.921 days and the mass of the outer planet M{sub c} ∼ 20 M{sub ⊕}. Additional transit photometry (especially for the outer planet) as well as precise radial-velocity measurements would be helpful to break the degeneracy and to determine the mass of the inner planet.

  10. Formation of planetary systems

    International Nuclear Information System (INIS)

    Brahic, A.

    1982-01-01

    It seemed appropriate to devote the 1980 School to the origin of the solar system and more particularly to the formation of planetary systems (dynamic accretion processes, small bodies, planetary rings, etc...) and to the physics and chemistry of planetary interiors, surface and atmospheres (physical and chemical constraints associated with their formation). This Summer School enabled both young researchers and hard-nosed scientists, gathered together in idyllic surroundings, to hold numerous discussions, to lay the foundations for future cooperation, to acquire an excellent basic understanding, and to make many useful contacts. This volume reflects the lectures and presentations that were delivered in this Summer School setting. It is aimed at both advanced students and research workers wishing to specialize in planetology. Every effort has been made to give an overview of the basic knowledge required in order to gain a better understanding of the origin of the solar system. Each article has been revised by one or two referees whom I would like to thank for their assistance. Between the end of the School in August 1980 and the publication of this volume in 1982, the Voyager probes have returned a wealth of useful information. Some preliminary results have been included for completeness

  11. High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP). II. Lucky Imaging results from 2015 and 2016

    Science.gov (United States)

    Evans, D. F.; Southworth, J.; Smalley, B.; Jørgensen, U. G.; Dominik, M.; Andersen, M. I.; Bozza, V.; Bramich, D. M.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Figuera Jaimes, R.; Gu, S.-H.; Hinse, T. C.; Henning, Th.; Hundertmark, M.; Kains, N.; Kerins, E.; Korhonen, H.; Kokotanekova, R.; Kuffmeier, M.; Longa-Peña, P.; Mancini, L.; MacKenzie, J.; Popovas, A.; Rabus, M.; Rahvar, S.; Sajadian, S.; Snodgrass, C.; Skottfelt, J.; Surdej, J.; Tronsgaard, R.; Unda-Sanzana, E.; von Essen, C.; Wang, Yi-Bo; Wertz, O.

    2018-02-01

    Context. The formation and dynamical history of hot Jupiters is currently debated, with wide stellar binaries having been suggested as a potential formation pathway. Additionally, contaminating light from both binary companions and unassociated stars can significantly bias the results of planet characterisation studies, but can be corrected for if the properties of the contaminating star are known. Aim. We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light. Methods: We analyse lucky imaging observations of 97 Southern hemisphere exoplanet host stars, using the Two Colour Instrument on the Danish 1.54 m telescope. For each detected companion star, we determine flux ratios relative to the planet host star in two passbands, and measure the relative position of the companion. The probability of each companion being physically associated was determined using our two-colour photometry. Results: A catalogue of close companion stars is presented, including flux ratios, position measurements, and estimated companion star temperature. For companions that are potential binary companions, we review archival and catalogue data for further evidence. For WASP-77AB and WASP-85AB, we combine our data with historical measurements to determine the binary orbits, showing them to be moderately eccentric and inclined to the line of sight (and hence planetary orbital axis). Combining our survey with the similar Friends of Hot Jupiters survey, we conclude that known hot Jupiter host stars show a deficit of high mass stellar companions compared to the field star population; however, this may be a result of the biases in detection and target selection by ground-based surveys. Based on data collected by

  12. Planetary mass function and planetary systems

    Science.gov (United States)

    Dominik, M.

    2011-02-01

    With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the properties of their respective host stars. This can be accounted for by describing planet populations by means of a differential planetary mass-radius-orbit function, which together with the fraction of stars with given properties that are orbited by planets and the stellar mass function allows the derivation of all statistics for any considered sample. These fundamental functions provide a framework for comparing statistics that result from different observing techniques and campaigns which all have their very specific selection procedures and detection efficiencies. Moreover, recent results both from gravitational microlensing campaigns and radial-velocity surveys of stars indicate that planets tend to cluster in systems rather than being the lonely child of their respective parent star. While planetary multiplicity in an observed system becomes obvious with the detection of several planets, its quantitative assessment however comes with the challenge to exclude the presence of further planets. Current exoplanet samples begin to give us first hints at the population statistics, whereas pictures of planet parameter space in its full complexity call for samples that are 2-4 orders of magnitude larger. In order to derive meaningful statistics, however, planet detection campaigns need to be designed in such a way that well-defined fully deterministic target selection, monitoring and detection criteria are applied. The probabilistic nature of gravitational microlensing makes this technique an illustrative example of all the encountered challenges and uncertainties.

  13. Transiting Exoplanet Monitoring Project (TEMP). IV. Refined System Parameters, Transit Timing Variations, and Orbital Stability of the Transiting Planetary System HAT-P-25

    Science.gov (United States)

    Wang, Xian-Yu; Wang, Songhu; Hinse, Tobias C.; Li, Kai; Wang, Yong-Hao; Laughlin, Gregory; Liu, Hui-Gen; Zhang, Hui; Wu, Zhen-Yu; Zhou, Xu; Zhou, Ji-Lin; Hu, Shao-Ming; Wu, Dong-Hong; Peng, Xi-Yan; Chen, Yuan-Yuan

    2018-06-01

    We present eight new light curves of the transiting extra-solar planet HAT-P-25b obtained from 2013 to 2016 with three telescopes at two observatories. We use the new light curves, along with recent literature material, to estimate the physical and orbital parameters of the transiting planet. Specifically, we determine the mid-transit times (T C ) and update the linear ephemeris, T C[0] = 2456418.80996 ± 0.00025 [BJDTDB] and P = 3.65281572 ± 0.00000095 days. We carry out a search for transit timing variations (TTVs), and find no significant TTV signal at the ΔT = 80 s-level, placing a limit on the possible strength of planet–planet interactions (TTVG). In the course of our analysis, we calculate the upper mass-limits of the potential nearby perturbers. Near the 1:2, 2:1, and 3:1 resonances with HAT-P-25b, perturbers with masses greater than 0.5, 0.3, and 0.5 M ⊕ respectively, can be excluded. Furthermore, based on the analysis of TTVs caused by light travel time effect (LTTE) we also eliminate the possibility that a long-period perturber exists with M p > 3000 MJ within a = 11.2 au of the parent star.

  14. Solar planetary systems stardust to terrestrial and extraterrestrial planetary sciences

    CERN Document Server

    Bhattacharya, Asit B

    2017-01-01

    The authors have put forth great efforts in gathering present day knowledge about different objects within our solar system and universe. This book features the most current information on the subject with information acquired from noted scientists in this area. The main objective is to convey the importance of the subject and provide detailed information on the physical makeup of our planetary system and technologies used for research. Information on educational projects has also been included in the Radio Astronomy chapters.This information is a real plus for students and educators considering a career in Planetary Science or for increasing their knowledge about our planetary system

  15. Characterization of the Wolf 1061 Planetary System

    Energy Technology Data Exchange (ETDEWEB)

    Kane, Stephen R.; Waters, Miranda A. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Von Braun, Kaspar [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Boyajian, Tabetha S. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Mann, Andrew W., E-mail: skane@sfsu.edu [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

    2017-02-01

    A critical component of exoplanetary studies is an exhaustive characterization of the host star, from which the planetary properties are frequently derived. Of particular value are the radius, temperature, and luminosity, which are key stellar parameters for studies of transit and habitability science. Here we present the results of new observations of Wolf 1061, known to host three super-Earths. Our observations from the Center for High Angular Resolution Astronomy interferometric array provide a direct stellar radius measurement of 0.3207±0.0088 R{sub ⊙}, from which we calculate the effective temperature and luminosity using spectral energy distribution models. We obtained 7 yr of precise, automated photometry that reveals the correct stellar rotation period of 89.3±1.8 days, finds no evidence of photometric transits, and confirms that the radial velocity signals are not due to stellar activity. Finally, our stellar properties are used to calculate the extent of the Habitable Zone (HZ) for the Wolf 1061 system, for which the optimistic boundaries are 0.09–0.23 au. Our simulations of the planetary orbital dynamics show that the eccentricity of the HZ planet oscillates to values as high as ∼0.15 as it exchanges angular momentum with the other planets in the system.

  16. Cognitive Planetary Transitions: An Astrobiological Perspective on the "Sapiezoic Eon".

    Science.gov (United States)

    Grinspoon, D. H.

    2016-12-01

    A powerful new dynamic is remaking Earth. Never before has a geological force become aware of its influence. A taxonomy of planetary catastrophes illuminates the unusual nature of the Anthropocene and reframes our current environmental predicaments as part of the narrative of planetary evolution. From a deep time perspective will the Anthropocene be an event, an interval, or something more significant? I propose that it is not simply an Epoch boundary, but the advent of Earth's 5th Eon, the "Sapiezoic". The advent of self-aware cognitive/geological processes as a component of planetary systems is potentially as significant as the other three Eon boundaries, each of which represented a shift in relationship between life and the planet. Yet, an Eon implies a permanently changed planet. This puts our immediate challenges over the next century: (stabilizing population & devising an energy system that can provide for the needs of this population without wrecking the natural systems upon which we depend) against the backdrop of a larger challenge: Becoming a long-term stabilizing factor on the planet. This will include: Over the next several hundred years, asteroid defense; Over tens of thousands of years, preventing ice ages and natural episodes of dangerous warming; Over billions of years, preventing runaway warming from solar evolution. Global influence precedes global control, so the earliest stages of this transition are characterized by unstable positive feedbacks threatening catastrophe. However, conscious awareness and control can also provide negative feedback. Becoming a stable part of the Earth system will require deep understanding of nature and an ability to forestall natural disasters, as well as the self-understanding needed to avoid self-imposed disasters. It will require both technical and spiritual progress. How we conduct ourselves on a global scale may affect the security and well-being of all future life. In the past when humans faced existential

  17. Dynamical habitability of planetary systems.

    Science.gov (United States)

    Dvorak, Rudolf; Pilat-Lohinger, Elke; Bois, Eric; Schwarz, Richard; Funk, Barbara; Beichman, Charles; Danchi, William; Eiroa, Carlos; Fridlund, Malcolm; Henning, Thomas; Herbst, Tom; Kaltenegger, Lisa; Lammer, Helmut; Léger, Alain; Liseau, René; Lunine, Jonathan; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Röttgering, Huub; Selsis, Frank; Schneider, Jean; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

    2010-01-01

    The problem of the stability of planetary systems, a question that concerns only multiplanetary systems that host at least two planets, is discussed. The problem of mean motion resonances is addressed prior to discussion of the dynamical structure of the more than 350 known planets. The difference with regard to our own Solar System with eight planets on low eccentricity is evident in that 60% of the known extrasolar planets have orbits with eccentricity e > 0.2. We theoretically highlight the studies concerning possible terrestrial planets in systems with a Jupiter-like planet. We emphasize that an orbit of a particular nature only will keep a planet within the habitable zone around a host star with respect to the semimajor axis and its eccentricity. In addition, some results are given for individual systems (e.g., Gl777A) with regard to the stability of orbits within habitable zones. We also review what is known about the orbits of planets in double-star systems around only one component (e.g., gamma Cephei) and around both stars (e.g., eclipsing binaries).

  18. Lunar and Planetary Science XXXV: Origin of Planetary Systems

    Science.gov (United States)

    2004-01-01

    The session titled Origin of Planetary Systems" included the following reports:Convective Cooling of Protoplanetary Disks and Rapid Giant Planet Formation; When Push Comes to Shove: Gap-opening, Disk Clearing and the In Situ Formation of Giant Planets; Late Injection of Radionuclides into Solar Nebula Analogs in Orion; Growth of Dust Particles and Accumulation of Centimeter-sized Objects in the Vicinity of a Pressure enhanced Region of a Solar Nebula; Fast, Repeatable Clumping of Solid Particles in Microgravity ; Chondrule Formation by Current Sheets in Protoplanetary Disks; Radial Migration of Phyllosilicates in the Solar Nebula; Accretion of the Outer Planets: Oligarchy or Monarchy?; Resonant Capture of Irregular Satellites by a Protoplanet ; On the Final Mass of Giant Planets ; Predicting the Atmospheric Composition of Extrasolar Giant Planets; Overturn of Unstably Stratified Fluids: Implications for the Early Evolution of Planetary Mantles; and The Evolution of an Impact-generated Partially-vaporized Circumplanetary Disk.

  19. Sustainable food systems for optimal planetary health.

    Science.gov (United States)

    Canavan, Chelsey R; Noor, Ramadhani A; Golden, Christopher D; Juma, Calestous; Fawzi, Wafaie

    2017-06-01

    Sustainable food systems are an important component of a planetary health strategy to reduce the threat of infectious disease, minimize environmental footprint and promote nutrition. Human population trends and dietary transition have led to growing demand for food and increasing production and consumption of meat, amid declining availability of arable land and water. The intensification of livestock production has serious environmental and infectious disease impacts. Land clearing for agriculture alters ecosystems, increases human-wildlife interactions and leads to disease proliferation. Context-specific interventions should be evaluated towards optimizing nutrition resilience, minimizing environmental footprint and reducing animal and human disease risk. © The Author 2017. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

  20. Post-main-sequence planetary system evolution

    Science.gov (United States)

    Veras, Dimitri

    2016-01-01

    The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level of theoretical scrutiny. Here, I review the diverse dynamical processes which affect planets, asteroids, comets and pebbles as their parent stars evolve into giant branch, white dwarf and neutron stars. This reference provides a foundation for the interpretation and modelling of currently known systems and upcoming discoveries. PMID:26998326

  1. Migration-induced architectures of planetary systems.

    Science.gov (United States)

    Szuszkiewicz, Ewa; Podlewska-Gaca, Edyta

    2012-06-01

    The recent increase in number of known multi-planet systems gives a unique opportunity to study the processes responsible for planetary formation and evolution. Special attention is given to the occurrence of mean-motion resonances, because they carry important information about the history of the planetary systems. At the early stages of the evolution, when planets are still embedded in a gaseous disc, the tidal interactions between the disc and planets cause the planetary orbital migration. The convergent differential migration of two planets embedded in a gaseous disc may result in the capture into a mean-motion resonance. The orbital migration taking place during the early phases of the planetary system formation may play an important role in shaping stable planetary configurations. An understanding of this stage of the evolution will provide insight on the most frequently formed architectures, which in turn are relevant for determining the planet habitability. The aim of this paper is to present the observational properties of these planetary systems which contain confirmed or suspected resonant configurations. A complete list of known systems with such configurations is given. This list will be kept by us updated from now on and it will be a valuable reference for studying the dynamics of extrasolar systems and testing theoretical predictions concerned with the origin and the evolution of planets, which are the most plausible places for existence and development of life.

  2. Planetary transit candidates in Corot-IRa01 field

    Science.gov (United States)

    Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.; Almenara, J.-M.; Bordé, P.; Bouchy, F.; Carone, L.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin, F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ofir, A.; Ollivier, M.; Janot-Pacheco, E.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.; Wuchterl, G.

    2009-10-01

    Context: CoRoT is a pioneering space mission devoted to the analysis of stellar variability and the photometric detection of extrasolar planets. Aims: We present the list of planetary transit candidates detected in the first field observed by CoRoT, IRa01, the initial run toward the Galactic anticenter, which lasted for 60 days. Methods: We analysed 3898 sources in the coloured bands and 5974 in the monochromatic band. Instrumental noise and stellar variability were taken into account using detrending tools before applying various transit search algorithms. Results: Fifty sources were classified as planetary transit candidates and the most reliable 40 detections were declared targets for follow-up ground-based observations. Two of these targets have so far been confirmed as planets, CoRoT-1b and CoRoT-4b, for which a complete characterization and specific studies were performed. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with contributions from Austria, Belgium, Brazil, ESA, Germany, and Spain. Four French laboratories associated with the CNRS (LESIA, LAM, IAS ,OMP) collaborate with CNES on the satellite development. First CoRoT data are available to the public from the CoRoT archive: http://idoc-corot.ias.u-psud.fr.

  3. Planetary ring systems properties, structures, and evolution

    CERN Document Server

    Murray, Carl D

    2018-01-01

    Planetary rings are among the most intriguing structures of our solar system and have fascinated generations of astronomers. Collating emerging knowledge in the field, this volume reviews our current understanding of ring systems with reference to the rings of Saturn, Uranus, Neptune, and more. Written by leading experts, the history of ring research and the basics of ring–particle orbits is followed by a review of the known planetary ring systems. All aspects of ring system science are described in detail, including specific dynamical processes, types of structures, thermal properties and their origins, and investigations using computer simulations and laboratory experiments. The concluding chapters discuss the prospects of future missions to planetary rings, the ways in which ring science informs and is informed by the study of other astrophysical disks, and a perspective on the field's future. Researchers of all levels will benefit from this thorough and engaging presentation.

  4. Allowed planetary orbits in the solar system

    International Nuclear Information System (INIS)

    Pintr, P.; Perinova, V.; Luks, A.

    2008-01-01

    A new law of the Titius-Bode type for planetary distances from the Sun is proposed. These distances for each planet are determined using appropriate nodal circle of a vibrating membrane. Regularities in the distribution of bodies in the solar system and in the systems of giant planets and some exoplanets are pointed out

  5. Communication System Architecture for Planetary Exploration

    Science.gov (United States)

    Braham, Stephen P.; Alena, Richard; Gilbaugh, Bruce; Glass, Brian; Norvig, Peter (Technical Monitor)

    2001-01-01

    Future human missions to Mars will require effective communications supporting exploration activities and scientific field data collection. Constraints on cost, size, weight and power consumption for all communications equipment make optimization of these systems very important. These information and communication systems connect people and systems together into coherent teams performing the difficult and hazardous tasks inherent in planetary exploration. The communication network supporting vehicle telemetry data, mission operations, and scientific collaboration must have excellent reliability, and flexibility.

  6. The final fate of planetary systems

    Science.gov (United States)

    Gaensicke, Boris

    2015-12-01

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

  7. Electrohydraulic drive system with planetary superposed gears

    Energy Technology Data Exchange (ETDEWEB)

    Graetz, A.; Klimek, K.H.; Welz, H.

    1989-01-01

    To prevent drive problems in ploughs the drives must be designed in such a way as to compensate for asymmetries. If electromechanical drives are replaced by an electrohydraulic drive system with superposed planetary gears and hydrostatic torque reaction supports the following advantages occur: load-free acceleration, load equalisation between main and auxiliary drive, overload protection, and reduction of systems vibrations. 2 figs., 2 tabs.

  8. On Some General Regularities of Formation of the Planetary Systems

    Directory of Open Access Journals (Sweden)

    Belyakov A. V.

    2014-01-01

    Full Text Available J.Wheeler’s geometrodynamic concept has been used, in which space continuum is considered as a topologically non-unitary coherent surface admitting the existence of transitions of the input-output kind between distant regions of the space in an additional dimension. This model assumes the existence of closed structures (micro- and macro- contours formed due to the balance between main interactions: gravitational, electric, magnetic, and inertial forces. It is such macrocontours that have been demonstrated to form — independently of their material basis — the essential structure of objects at various levels of organization of matter. On the basis of this concept in this paper basic regularities acting during formation planetary systems have been obtained. The existence of two sharply different types of planetary systems has been determined. The dependencies linking the masses of the planets, the diameters of the planets, the orbital radii of the planet, and the mass of the central body have been deduced. The possibility of formation of Earth-like planets near brown dwarfs has been grounded. The minimum mass of the planet, which may arise in the planetary system, has been defined.

  9. The architecture and formation of the Kepler-30 planetary system

    Science.gov (United States)

    Panichi, F.; Goździewski, K.; Migaszewski, C.; Szuszkiewicz, E.

    2018-04-01

    We study the orbital architecture, physical characteristics of planets, formation and long-term evolution of the Kepler-30 planetary system, detected and announced in 2012 by the KEPLER team. We show that the Kepler-30 system belongs to a particular class of very compact and quasi-resonant, yet long-term stable planetary systems. We re-analyse the light curves of the host star spanning Q1-Q17 quarters of the KEPLER mission. A huge variability of the Transit Timing Variations (TTV) exceeding 2 days is induced by a massive Jovian planet located between two Neptune-like companions. The innermost pair is near to the 2:1 mean motion resonance (MMR), and the outermost pair is close to higher order MMRs, such as 17:7 and 7:3. Our re-analysis of photometric data allows us to constrain, better than before, the orbital elements, planets' radii and masses, which are 9.2 ± 0.1, 536 ± 5, and 23.7 ± 1.3 Earth masses for Kepler-30b, Kepler-30c and Kepler-30d, respectively. The masses of the inner planets are determined within ˜1% uncertainty. We infer the internal structures of the Kepler-30 planets and their bulk densities in a wide range from (0.19 ± 0.01) g.cm-3 for Kepler-30d, (0.96 ± 0.15) g.cm-3 for Kepler-30b, to (1.71 ± 0.13) g.cm-3 for the Jovian planet Kepler-30c. We attempt to explain the origin of this unique planetary system and a deviation of the orbits from exact MMRs through the planetary migration scenario. We anticipate that the Jupiter-like planet plays an important role in determining the present dynamical state of this system.

  10. The GAPS programme with HARPS-N at TNG. XVI. Measurement of the Rossiter-McLaughlin effect of transiting planetary systems HAT-P-3, HAT-P-12, HAT-P-22, WASP-39, and WASP-60

    Science.gov (United States)

    Mancini, L.; Esposito, M.; Covino, E.; Southworth, J.; Biazzo, K.; Bruni, I.; Ciceri, S.; Evans, D.; Lanza, A. F.; Poretti, E.; Sarkis, P.; Smith, A. M. S.; Brogi, M.; Affer, L.; Benatti, S.; Bignamini, A.; Boccato, C.; Bonomo, A. S.; Borsa, F.; Carleo, I.; Claudi, R.; Cosentino, R.; Damasso, M.; Desidera, S.; Giacobbe, P.; González-Álvarez, E.; Gratton, R.; Harutyunyan, A.; Leto, G.; Maggio, A.; Malavolta, L.; Maldonado, J.; Martinez-Fiorenzano, A.; Masiero, S.; Micela, G.; Molinari, E.; Nascimbeni, V.; Pagano, I.; Pedani, M.; Piotto, G.; Rainer, M.; Scandariato, G.; Smareglia, R.; Sozzetti, A.; Andreuzzi, G.; Henning, Th.

    2018-05-01

    Context. The measurement of the orbital obliquity of hot Jupiters with different physical characteristics can provide clues to the mechanisms of migration and orbital evolution of this particular class of giant exoplanets. Aims: We aim to derive the degree of alignment between planetary orbit and stellar spin angular momentum vectors and look for possible links with other orbital and fundamental physical parameters of the star-planet system. We focus on the characterisation of five transiting planetary systems (HAT-P-3, HAT-P-12, HAT-P-22, WASP-39, and WASP-60) and the determination of their sky-projected planet orbital obliquity through the measurement of the Rossiter-McLaughlin effect. Methods: We used HARPS-N high-precision radial velocity measurements, gathered during transit events, to measure the Rossiter-McLaughlin effect in the target systems and determine the sky-projected angle between the planetary orbital plane and stellar equator. The characterisation of stellar atmospheric parameters was performed by exploiting the HARPS-N spectra, using line equivalent width ratios and spectral synthesis methods. Photometric parameters of the five transiting exoplanets were re-analysed through 17 new light curves, obtained with an array of medium-class telescopes, and other light curves from the literature. Survey-time-series photometric data were analysed for determining the rotation periods of the five stars and their spin inclination. Results: From the analysis of the Rossiter-McLaughlin effect we derived a sky-projected obliquity of λ = 21.2° ± 8.7°, λ = -54°-13°+41°, λ = -2.1° ± 3.0°, λ = 0° ± 11°, and λ = -129° ± 17° for HAT-P-3 b, HAT-P-12 b, HAT-P-22 b, WASP-39 b, and WASP-60 b, respectively. The latter value indicates that WASP-60 b is moving on a retrograde orbit. These values represent the first measurements of λ for the five exoplanetary systems under study. The stellar activity of HAT-P-22 indicates a rotation period of 28.7 ± 0

  11. Robo-AO Kepler Survey. IV. The Effect of Nearby Stars on 3857 Planetary Candidate Systems

    Science.gov (United States)

    Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Riddle, Reed; Duev, Dmitry A.; Howard, Ward; Jensen-Clem, Rebecca; Kulkarni, S. R.; Morton, Tim; Salama, Maïssa

    2018-04-01

    We present the overall statistical results from the Robo-AO Kepler planetary candidate survey, comprising of 3857 high-angular resolution observations of planetary candidate systems with Robo-AO, an automated laser adaptive optics system. These observations reveal previously unknown nearby stars blended with the planetary candidate host stars that alter the derived planetary radii or may be the source of an astrophysical false positive transit signal. In the first three papers in the survey, we detected 440 nearby stars around 3313 planetary candidate host stars. In this paper, we present observations of 532 planetary candidate host stars, detecting 94 companions around 88 stars; 84 of these companions have not previously been observed in high resolution. We also report 50 more-widely separated companions near 715 targets previously observed by Robo-AO. We derive corrected planetary radius estimates for the 814 planetary candidates in systems with a detected nearby star. If planetary candidates are equally likely to orbit the primary or secondary star, the radius estimates for planetary candidates in systems with likely bound nearby stars increase by a factor of 1.54, on average. We find that 35 previously believed rocky planet candidates are likely not rocky due to the presence of nearby stars. From the combined data sets from the complete Robo-AO KOI survey, we find that 14.5 ± 0.5% of planetary candidate hosts have a nearby star with 4″, while 1.2% have two nearby stars, and 0.08% have three. We find that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of Jupiter-sized planet candidates have detected nearby stars.

  12. Gravitational waves emitted by extrasolar planetary systems

    International Nuclear Information System (INIS)

    Berti, E.; Ferrari, V.

    2001-01-01

    The recently discovered Extrasolar Planetary Systems (EPS's) are potentially interesting sources of gravitational waves, since they are very close to Earth (at distances ∼ 10 pc), and their orbital features and positions in the sky are quite well known. As a first estimate, we compute the orbital emission of these systems using the quadrupole formula. Then we show that, in principle, the orbiting planet could resonantly excite the quasi-normal modes of the central star. We use the general-relativistic theory of stellar pulsations to estimate the effects of such a resonance on the gravitational-wave emission of the system. We also consider radiation-reaction effects on the orbital evolution, and give upper limits on the timescales required for a planet to get off-resonance. (author)

  13. The Role of NASA's Planetary Data System in the Planetary Spatial Data Infrastructure Initiative

    Science.gov (United States)

    Arvidson, R. E.; Gaddis, L. R.

    2017-12-01

    An effort underway in NASA's planetary science community is the Mapping and Planetary Spatial Infrastructure Team (MAPSIT, http://www.lpi.usra.edu/mapsit/). MAPSIT is a community assessment group organized to address a lack of strategic spatial data planning for space science and exploration. Working with MAPSIT, a new initiative of NASA and USGS is the development of a Planetary Spatial Data Infrastructure (PSDI) that builds on extensive knowledge on storing, accessing, and working with terrestrial spatial data. PSDI is a knowledge and technology framework that enables the efficient discovery, access, and exploitation of planetary spatial data to facilitate data analysis, knowledge synthesis, and decision-making. NASA's Planetary Data System (PDS) archives >1.2 petabytes of digital data resulting from decades of planetary exploration and research. The PDS charter focuses on the efficient collection, archiving, and accessibility of these data. The PDS emphasis on data preservation and archiving is complementary to that of the PSDI initiative because the latter utilizes and extends available data to address user needs in the areas of emerging technologies, rapid development of tailored delivery systems, and development of online collaborative research environments. The PDS plays an essential PSDI role because it provides expertise to help NASA missions and other data providers to organize and document their planetary data, to collect and maintain the archives with complete, well-documented and peer-reviewed planetary data, to make planetary data accessible by providing online data delivery tools and search services, and ultimately to ensure the long-term preservation and usability of planetary data. The current PDS4 information model extends and expands PDS metadata and relationships between and among elements of the collections. The PDS supports data delivery through several node services, including the Planetary Image Atlas (https

  14. In-situ Planetary Subsurface Imaging System

    Science.gov (United States)

    Song, W.; Weber, R. C.; Dimech, J. L.; Kedar, S.; Neal, C. R.; Siegler, M.

    2017-12-01

    Geophysical and seismic instruments are considered the most effective tools for studying the detailed global structures of planetary interiors. A planet's interior bears the geochemical markers of its evolutionary history, as well as its present state of activity, which has direct implications to habitability. On Earth, subsurface imaging often involves massive data collection from hundreds to thousands of geophysical sensors (seismic, acoustic, etc) followed by transfer by hard links or wirelessly to a central location for post processing and computing, which will not be possible in planetary environments due to imposed mission constraints on mass, power, and bandwidth. Emerging opportunities for geophysical exploration of the solar system from Venus to the icy Ocean Worlds of Jupiter and Saturn dictate that subsurface imaging of the deep interior will require substantial data reduction and processing in-situ. The Real-time In-situ Subsurface Imaging (RISI) technology is a mesh network that senses and processes geophysical signals. Instead of data collection then post processing, the mesh network performs the distributed data processing and computing in-situ, and generates an evolving 3D subsurface image in real-time that can be transmitted under bandwidth and resource constraints. Seismic imaging algorithms (including traveltime tomography, ambient noise imaging, and microseismic imaging) have been successfully developed and validated using both synthetic and real-world terrestrial seismic data sets. The prototype hardware system has been implemented and can be extended as a general field instrumentation platform tailored specifically for a wide variety of planetary uses, including crustal mapping, ice and ocean structure, and geothermal systems. The team is applying the RISI technology to real off-world seismic datasets. For example, the Lunar Seismic Profiling Experiment (LSPE) deployed during the Apollo 17 Moon mission consisted of four geophone instruments

  15. Polarimetry of stars and planetary systems

    National Research Council Canada - National Science Library

    Kolokolova, Ludmilla; Hough, James; Levasseur-Regourd, Anny-Chantal

    2015-01-01

    ... fields of polarimetric exploration, including proto-planetary and debris discs, icy satellites, transneptunian objects, exoplanets and the search for extraterrestrial life -- unique results produced...

  16. An autopsy of dead planetary systems with COS

    Science.gov (United States)

    Debes, John

    2014-10-01

    We propose to use HST/COS to conduct autopsies of dead planetary systems around UV bright hydrogen-white dwarfs (WDs), which have dust disks found via their mid-IR emission in excess of that expected from the photosphere. As part of a WISE survey, and followed up with a combination of NASA Keck HIRES/Magellan MIKE optical spectroscopy, we have identified three new systems that are accreting dust. These WDs are bright in the mid-IR and UV, gold-standard targets for studies with HST/COS and later with JWST. The dusty material is debris resulting from the tidal disruption of exo-asteroids that accrete onto the WD surface. Many atomic elements from the accreted and dissociated dust particles are detectable with COS, enabling abundance determinations of exo-asteroidal material. Moreover, the photospheric abundances of this material can be directly compared with a determination of the dust mineralogy obtained with future JWST mid-IR spectroscopy-our proposed UV observations provide complementary constraints on mineralogical compositions of the accreting dust particles. UV spectroscopy is crucial for cataloging elemental abundances for these exo-asteroids. For the majority of WDs, optical spectroscopy reveals only a couple of lines of Ca or Mg, while UV spectroscopy captures lines from Al, Fe, Si, C, Ni, O, S, Cr, P, and Ti. Obtaining the elemental abundances of exo-asteroids is comparable to the spectroscopic characterization of transiting exoplanets or protoplanetary disks-all of these techniques determine how the chemical diversity of planetary systems translate into planetary architectures and the probability of habitable planets around solar-type stars.

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

    CERN Document Server

    Milone, Eugene F

    2014-01-01

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

  18. Planetary rovers robotic exploration of the solar system

    CERN Document Server

    Ellery, Alex

    2016-01-01

    The increasing adoption of terrain mobility – planetary rovers – for the investigation of planetary surfaces emphasises their central importance in space exploration. This imposes a completely new set of technologies and methodologies to the design of such spacecraft – and planetary rovers are indeed, first and foremost, spacecraft. This introduces vehicle engineering, mechatronics, robotics, artificial intelligence and associated technologies to the spacecraft engineer’s repertoire of skills. Planetary Rovers is the only book that comprehensively covers these aspects of planetary rover engineering and more. The book: • discusses relevant planetary environments to rover missions, stressing the Moon and Mars; • includes a brief survey of previous rover missions; • covers rover mobility, traction and control systems; • stresses the importance of robotic vision in rovers for both navigation and science; • comprehensively covers autonomous navigation, path planning and multi-rover formations on ...

  19. The diversity of planetary system architectures: contrasting theory with observations

    Science.gov (United States)

    Miguel, Y.; Guilera, O. M.; Brunini, A.

    2011-10-01

    In order to explain the observed diversity of planetary system architectures and relate this primordial diversity to the initial properties of the discs where they were born, we develop a semi-analytical model for computing planetary system formation. The model is based on the core instability model for the gas accretion of the embryos and the oligarchic growth regime for the accretion of the solid cores. Two regimes of planetary migration are also included. With this model, we consider different initial conditions based on recent results of protoplanetary disc observations to generate a variety of planetary systems. These systems are analysed statistically, exploring the importance of several factors that define the planetary system birth environment. We explore the relevance of the mass and size of the disc, metallicity, mass of the central star and time-scale of gaseous disc dissipation in defining the architecture of the planetary system. We also test different values of some key parameters of our model to find out which factors best reproduce the diverse sample of observed planetary systems. We assume different migration rates and initial disc profiles, in the context of a surface density profile motivated by similarity solutions. According to this, and based on recent protoplanetary disc observational data, we predict which systems are the most common in the solar neighbourhood. We intend to unveil whether our Solar system is a rarity or whether more planetary systems like our own are expected to be found in the near future. We also analyse which is the more favourable environment for the formation of habitable planets. Our results show that planetary systems with only terrestrial planets are the most common, being the only planetary systems formed when considering low-metallicity discs, which also represent the best environment for the development of rocky, potentially habitable planets. We also found that planetary systems like our own are not rare in the

  20. The signatures of the parental cluster on field planetary systems

    Science.gov (United States)

    Cai, Maxwell Xu; Portegies Zwart, Simon; van Elteren, Arjen

    2018-03-01

    Due to the high stellar densities in young clusters, planetary systems formed in these environments are likely to have experienced perturbations from encounters with other stars. We carry out direct N-body simulations of multiplanet systems in star clusters to study the combined effects of stellar encounters and internal planetary dynamics. These planetary systems eventually become part of the Galactic field population as the parental cluster dissolves, which is where most presently known exoplanets are observed. We show that perturbations induced by stellar encounters lead to distinct signatures in the field planetary systems, most prominently, the excited orbital inclinations and eccentricities. Planetary systems that form within the cluster's half-mass radius are more prone to such perturbations. The orbital elements are most strongly excited in the outermost orbit, but the effect propagates to the entire planetary system through secular evolution. Planet ejections may occur long after a stellar encounter. The surviving planets in these reduced systems tend to have, on average, higher inclinations and larger eccentricities compared to systems that were perturbed less strongly. As soon as the parental star cluster dissolves, external perturbations stop affecting the escaped planetary systems, and further evolution proceeds on a relaxation time-scale. The outer regions of these ejected planetary systems tend to relax so slowly that their state carries the memory of their last strong encounter in the star cluster. Regardless of the stellar density, we observe a robust anticorrelation between multiplicity and mean inclination/eccentricity. We speculate that the `Kepler dichotomy' observed in field planetary systems is a natural consequence of their early evolution in the parental cluster.

  1. The Planetary Data System Web Catalog Interface--Another Use of the Planetary Data System Data Model

    Science.gov (United States)

    Hughes, S.; Bernath, A.

    1995-01-01

    The Planetary Data System Data Model consists of a set of standardized descriptions of entities within the Planetary Science Community. These can be real entities in the space exploration domain such as spacecraft, instruments, and targets; conceptual entities such as data sets, archive volumes, and data dictionaries; or the archive data products such as individual images, spectrum, series, and qubes.

  2. The Planetary Data System Distributed Inventory System

    Science.gov (United States)

    Hughes, J. Steven; McMahon, Susan K.

    1996-01-01

    The advent of the World Wide Web (Web) and the ability to easily put data repositories on-line has resulted in a proliferation of digital libraries. The heterogeneity of the underlying systems, the autonomy of the individual sites, and distributed nature of the technology has made both interoperability across the sites and the search for resources within a site major research topics. This article will describe a system that addresses both issues using standard Web protocols and meta-data labels to implement an inventory of on-line resources across a group of sites. The success of this system is strongly dependent on the existence of and adherence to a standards architecture that guides the management of meta-data within participating sites.

  3. Polarimetry Microlensing of Close-in Planetary Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sajadian, Sedighe [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Hundertmark, Markus, E-mail: s.sajadian@cc.iut.ac.ir [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg (Germany)

    2017-04-01

    A close-in giant planetary (CGP) system has a net polarization signal whose value varies depending on the orbital phase of the planet. This polarization signal is either caused by the stellar occultation or by reflected starlight from the surface of the orbiting planet. When the CGP system is located in the Galactic bulge, its polarization signal becomes too weak to be measured directly. One method for detecting and characterizing these weak polarization signatures due to distant CGP systems is gravitational microlensing. In this work, we focus on potential polarimetric observations of highly magnified microlensing events of CGP systems. When the lens is passing directly in front of the source star with its planetary companion, the polarimetric signature caused by the transiting planet is magnified. As a result, some distinct features in the polarimetry and light curves are produced. In the same way, microlensing amplifies the reflection-induced polarization signal. While the planet-induced perturbations are magnified whenever these polarimetric or photometric deviations vanish for a moment, the corresponding magnification factor of the polarization component(s) is related to the planet itself. Finding these exact times in the planet-induced perturbations helps us to characterize the planet. In order to evaluate the observability of such systems through polarimetric or photometric observations of high-magnification microlensing events, we simulate these events by considering confirmed CGP systems as their source stars and conclude that the efficiency for detecting the planet-induced signal with the state-of-the-art polarimetric instrument (FORS2/VLT) is less than 0.1%. Consequently, these planet-induced polarimetry perturbations can likely be detected under favorable conditions by the high-resolution and short-cadence polarimeters of the next generation.

  4. Polarimetry Microlensing of Close-in Planetary Systems

    International Nuclear Information System (INIS)

    Sajadian, Sedighe; Hundertmark, Markus

    2017-01-01

    A close-in giant planetary (CGP) system has a net polarization signal whose value varies depending on the orbital phase of the planet. This polarization signal is either caused by the stellar occultation or by reflected starlight from the surface of the orbiting planet. When the CGP system is located in the Galactic bulge, its polarization signal becomes too weak to be measured directly. One method for detecting and characterizing these weak polarization signatures due to distant CGP systems is gravitational microlensing. In this work, we focus on potential polarimetric observations of highly magnified microlensing events of CGP systems. When the lens is passing directly in front of the source star with its planetary companion, the polarimetric signature caused by the transiting planet is magnified. As a result, some distinct features in the polarimetry and light curves are produced. In the same way, microlensing amplifies the reflection-induced polarization signal. While the planet-induced perturbations are magnified whenever these polarimetric or photometric deviations vanish for a moment, the corresponding magnification factor of the polarization component(s) is related to the planet itself. Finding these exact times in the planet-induced perturbations helps us to characterize the planet. In order to evaluate the observability of such systems through polarimetric or photometric observations of high-magnification microlensing events, we simulate these events by considering confirmed CGP systems as their source stars and conclude that the efficiency for detecting the planet-induced signal with the state-of-the-art polarimetric instrument (FORS2/VLT) is less than 0.1%. Consequently, these planet-induced polarimetry perturbations can likely be detected under favorable conditions by the high-resolution and short-cadence polarimeters of the next generation.

  5. Connecting the Astrophysics Data System and Planetary Data System

    Science.gov (United States)

    Eichhorn, G.; Kurtz, M. J.; Accomazzi, A.; Grant, C. S.; Murray, S. S.; Hughes, J. S.; Mortellaro, J.; McMahon, S. K.

    1997-07-01

    The Astrophysics Data System (ADS) provides access to astronomical literature through a sophisticated search engine. Over 10,000 users retrieve almost 5 million references and read more than 25,000 full text articles per month. ADS cooperates closely with all the main astronomical journals and data centers to create and maintain a state-of-the-art digital library. The Planetary Data System (PDS) publishes high quality peer reviewed planetary science data products, defines planetary archiving standards to make products usable, and provides science expertise to users in data product preparation and use. Data products are available to users on CD media, with more than 600 CD-ROM titles in the inventory from past missions as well as the recent releases from active planetary missions and observations. The ADS and PDS serve overlapping communities and offer complementary functions. The ADS and PDS are both part of the NASA Space Science Data System, sponsored by the Office of Space Science, which curates science data products for researchers and the general public. We are in the process of connecting these two data systems. As a first step we have included entries for PDS data sets in the ADS abstract service. This allows ADS users to find PDS data sets by searching for their descriptions through the ADS search system. The information returned from the ADS links directly to the data set's entry in the PDS data set catalog. After linking to this catalog, the user will have access to more comprehensive data set information, related ancillary information, and on-line data products. The PDS on the other hand will use the ADS to provide access to bibliographic information. This includes links from PDS data set catalog bibliographic citations to ADS abstracts and on-line articles. The cross-linking between these data systems allows each system to concentrate on its main objectives and utilize the other system to provide more and improved services to the users of both systems.

  6. Nonlinear time heteronymous damping in nonlinear parametric planetary systems

    Czech Academy of Sciences Publication Activity Database

    Hortel, Milan; Škuderová, Alena

    2014-01-01

    Roč. 225, č. 7 (2014), s. 2059-2073 ISSN 0001-5970 Institutional support: RVO:61388998 Keywords : nonlinear dynamics * planetary systems * heteronymous damping Subject RIV: JT - Propulsion, Motors ; Fuels Impact factor: 1.465, year: 2014

  7. A Population of planetary systems characterized by short-period, Earth-sized planets

    Science.gov (United States)

    Steffen, Jason H.; Coughlin, Jeffrey L.

    2016-01-01

    We analyze data from the Quarter 1–17 Data Release 24 (Q1–Q17 DR24) planet candidate catalog from NASA’s Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined (≳17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters. PMID:27790984

  8. A Population of planetary systems characterized by short-period, Earth-sized planets.

    Science.gov (United States)

    Steffen, Jason H; Coughlin, Jeffrey L

    2016-10-25

    We analyze data from the Quarter 1-17 Data Release 24 (Q1-Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined ([Formula: see text]17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

  9. Planetary transit candidates in the CoRoT-SRc01 field

    DEFF Research Database (Denmark)

    Erikson, A.; Santerne, A.; Renner, S.

    2012-01-01

    Context. CoRoT is a pioneering space mission whose primary goals are stellar seismology and extrasolar planets search. Its surveys of large stellar fields generate numerous planetary candidates whose lightcurves have transit-like features. An extensive analytical and observational follow-up effort...... is undertaken to classify these candidates. Aims. We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. Methods. We acquired...... and analyzed 7470 chromatic and 3938 monochromatic lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves. Results. Fifty-one stars were classified...

  10. Planetary Protection Considerations in EVA System Design

    Science.gov (United States)

    Eppler, Dean B.; Kosmo, Joseph J.

    2011-01-01

    very little expression of these anomalies. hardware from the human-occupied area may limit (although not likely eliminate) external materials in the human habitat. Definition of design-to requirements is critical to understanding technical feasibility and costs. The definition of Planetary Protection needs in relation to EVA mission and system element development cost impacts should be considered and interpreted in terms of Plausible Protection criteria. Since EVA operations will have the most direct physical interaction with the Martian surface, PP needs should be considered in the terms of mitigating hardware and operations impacts and costs.

  11. Planetary Formation and Dynamics in Binary Systems

    Science.gov (United States)

    Xie, J. W.

    2013-01-01

    As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a

  12. The planetary system to KIC 11442793: A compact analogue to the solar system

    International Nuclear Information System (INIS)

    Cabrera, J.; Csizmadia, Sz.; Rauer, H.; Erikson, A.; Dreyer, C.; Eigmüller, Ph.; Lehmann, H.; Hatzes, A.; Dvorak, R.; Gandolfi, D.

    2014-01-01

    We announce the discovery of a planetary system with seven transiting planets around a Kepler target, a current record for transiting systems. Planets b, c, e, and f are reported for the first time in this work. Planets d, g, and h were previously reported in the literature, although here we revise their orbital parameters and validate their planetary nature. Planets h and g are gas giants and show strong dynamical interactions. The orbit of planet g is perturbed in such a way that its orbital period changes by 25.7 hr between two consecutive transits during the length of the observations, which is the largest such perturbation found so far. The rest of the planets also show mutual interactions: planets d, e, and f are super-Earths close to a mean motion resonance chain (2:3:4), and planets b and c, with sizes below 2 Earth radii, are within 0.5% of the 4:5 mean motion resonance. This complex system presents some similarities to our solar system, with small planets in inner orbits and gas giants in outer orbits. It is, however, more compact. The outer planet has an orbital distance around 1 AU, and the relative position of the gas giants is opposite to that of Jupiter and Saturn, which is closer to the expected result of planet formation theories. The dynamical interactions between planets are also much richer.

  13. LBT observations of the HR8799 planetary system

    Science.gov (United States)

    Mesa, D.; Arcidiacono, C.; Claudi, R. U.; Desidera, S.; Esposito, S.; Gratton, R.; Masciadri, E.

    2013-09-01

    We present here observations of the HR8799 planetary system performed in H and Ks band exploiting the AO system at the Large Binocular Telescope and the PISCES camera. Thanks to the excellent performence of the instrument we were able to detect for the first time the inner known planet of the system (HR8799) in the H band. Precise photometric and astrometric measures have been taken for all the four planets. Further, exploiting ours and previous astrometric results, we were able to put some limits on the planetary orbits of the four planets. The analysis of the dinamical stability of the system seems to show lower planetary masses than the ones adopted until now.

  14. Detection limits for close eclipsing and transiting sub-stellar and planetary companions to white dwarfs in the WASP survey

    OpenAIRE

    Faedi, F.; West, R. G.; Burleigh, M. R.; Goad, M. R.; Hebb, L.

    2010-01-01

    We have performed extensive simulations to explore the possibility of detecting eclipses and transits of close, sub-stellar and planetary companions to white dwarfs in WASP light-curves. Our simulations cover companions $\\sim0.3\\Re

  15. Planetary transit candidates in CoRoT LRa01 field

    DEFF Research Database (Denmark)

    Carone, L.; Gandolfi, D.; Cabrera, J.

    2012-01-01

    We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. We acquired and analyzed 7470 chromatic and 3938 monochromatic...... lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves. (2 data files)....

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

    Science.gov (United States)

    Stanboli, Alice; McAuley, James M.

    2013-01-01

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

  17. UNSTABLE PLANETARY SYSTEMS EMERGING OUT OF GAS DISKS

    International Nuclear Information System (INIS)

    Matsumura, Soko; Thommes, Edward W.; Chatterjee, Sourav; Rasio, Frederic A.

    2010-01-01

    The discovery of over 400 extrasolar planets allows us to statistically test our understanding of the formation and dynamics of planetary systems via numerical simulations. Traditional N-body simulations of multiple-planet systems without gas disks have successfully reproduced the eccentricity (e) distribution of the observed systems by assuming that the planetary systems are relatively closely packed when the gas disk dissipates, so that they become dynamically unstable within the stellar lifetime. However, such studies cannot explain the small semimajor axes a of extrasolar planetary systems, if planets are formed, as the standard planet formation theory suggests, beyond the ice line. In this paper, we numerically study the evolution of three-planet systems in dissipating gas disks, and constrain the initial conditions that reproduce the observed a and e distributions simultaneously. We adopt initial conditions that are motivated by the standard planet formation theory, and self-consistently simulate the disk evolution and planet migration, by using a hybrid N-body and one-dimensional gas disk code. We also take into account eccentricity damping, and investigate the effect of saturation of corotation resonances on the evolution of planetary systems. We find that the a distribution is largely determined in a gas disk, while the e distribution is determined after the disk dissipation. We also find that there may be an optimum disk mass which leads to the observed a-e distribution. Our simulations generate a larger fraction of planetary systems trapped in mean-motion resonances (MMRs) than the observations, indicating that the disk's perturbation to the planetary orbits may be important to explain the observed rate of MMRs. We also find a much lower occurrence of planets on retrograde orbits than the current observations of close-in planets suggest.

  18. Determination of hyperfine-induced transition rates from observations of a planetary nebula.

    Science.gov (United States)

    Brage, Tomas; Judge, Philip G; Proffitt, Charles R

    2002-12-31

    Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p 3P(o)(0)-->2s2 1S0 in the berylliumlike emission line spectrum of N IV at 1487.89 A. A nebular model allows us to confirm a transition rate of 4x10(-4) sec(-1)+/-33% for this line. The measurement represents the first independent confirmation of the transition rate of hyperfine-induced lines in low ionization stages, and it provides support for the techniques used to compute these transitions for the determination of very low densities and isotope ratios.

  19. The complex planetary synchronization structure of the solar system

    Science.gov (United States)

    Scafetta, N.

    2014-01-01

    The complex planetary synchronization structure of the solar system, which since Pythagoras of Samos (ca. 570-495 BC) is known as the music of the spheres, is briefly reviewed from the Renaissance up to contemporary research. Copernicus' heliocentric model from 1543 suggested that the planets of our solar system form a kind of mutually ordered and quasi-synchronized system. From 1596 to 1619 Kepler formulated preliminary mathematical relations of approximate commensurabilities among the planets, which were later reformulated in the Titius-Bode rule (1766-1772), which successfully predicted the orbital position of Ceres and Uranus. Following the discovery of the ~ 11 yr sunspot cycle, in 1859 Wolf suggested that the observed solar variability could be approximately synchronized with the orbital movements of Venus, Earth, Jupiter and Saturn. Modern research has further confirmed that (1) the planetary orbital periods can be approximately deduced from a simple system of resonant frequencies; (2) the solar system oscillates with a specific set of gravitational frequencies, and many of them (e.g., within the range between 3 yr and 100 yr) can be approximately constructed as harmonics of a base period of ~ 178.38 yr; and (3) solar and climate records are also characterized by planetary harmonics from the monthly to the millennial timescales. This short review concludes with an emphasis on the contribution of the author's research on the empirical evidences and physical modeling of both solar and climate variability based on astronomical harmonics. The general conclusion is that the solar system works as a resonator characterized by a specific harmonic planetary structure that also synchronizes the Sun's activity and the Earth's climate. The special issue Pattern in solar variability, their planetary origin and terrestrial impacts (Mörner et al., 2013) further develops the ideas about the planetary-solar-terrestrial interaction with the personal contribution of 10

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

    CERN Document Server

    Milone, Eugene F

    2008-01-01

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

  1. The occurrence of Jovian planets and the habitability of planetary systems

    OpenAIRE

    Lunine, Jonathan I.

    2001-01-01

    Planets of mass comparable to or larger than Jupiter's have been detected around over 50 stars, and for one such object a definitive test of its nature as a gas giant has been accomplished with data from an observed planetary transit. By virtue of their strong gravitational pull, giant planets define the dynamical and collisional environment within which terrestrial planets form. In our solar system, the position and timing of the formation of Jupiter determined the am...

  2. System Geometries and Transit/Eclipse Probabilities

    Directory of Open Access Journals (Sweden)

    Howard A.

    2011-02-01

    Full Text Available Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS.

  3. Small reactor power systems for manned planetary surface bases

    Energy Technology Data Exchange (ETDEWEB)

    Bloomfield, H.S.

    1987-12-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

  4. Small reactor power systems for manned planetary surface bases

    International Nuclear Information System (INIS)

    Bloomfield, H.S.

    1987-12-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options

  5. Parametric modal transition systems

    DEFF Research Database (Denmark)

    Beneš, Nikola; Křetínský, Jan; Larsen, Kim Guldstrand

    2011-01-01

    Modal transition systems (MTS) is a well-studied specification formalism of reactive systems supporting a step-wise refinement methodology. Despite its many advantages, the formalism as well as its currently known extensions are incapable of expressing some practically needed aspects in the refin......Modal transition systems (MTS) is a well-studied specification formalism of reactive systems supporting a step-wise refinement methodology. Despite its many advantages, the formalism as well as its currently known extensions are incapable of expressing some practically needed aspects...

  6. Planetary Systems Detection, Formation and Habitability of Extrasolar Planets

    CERN Document Server

    Ollivier, Marc; Casoli, Fabienne; Encrenaz, Thérèse; Selsis, Franck

    2009-01-01

    Over the past ten years, the discovery of extrasolar planets has opened a new field of astronomy, and this area of research is rapidly growing, from both the observational and theoretical point of view. The presence of many giant exoplanets in the close vicinity of their star shows that these newly discovered planetary systems are very different from the solar system. New theoretical models are being developed in order to understand their formation scenarios, and new observational methods are being implemented to increase the sensitivity of exoplanet detections. In the present book, the authors address the question of planetary systems from all aspects. Starting from the facts (the detection of more than 300 extraterrestrial planets), they first describe the various methods used for these discoveries and propose a synthetic analysis of their global properties. They then consider the observations of young stars and circumstellar disks and address the case of the solar system as a specific example, different fr...

  7. Planetary nebulae

    International Nuclear Information System (INIS)

    Amnuehl', P.R.

    1985-01-01

    The history of planetary nebulae discovery and their origin and evolution studies is discussed in a popular way. The problem of planetary nebulae central star is considered. The connection between the white-draft star and the planetary nebulae formulation is shown. The experimental data available acknowledge the hypothesis of red giant - planetary nebula nucleus - white-draft star transition process. Masses of planetary nebulae white-draft stars and central stars are distributed practically similarly: the medium mass is close to 0.6Msub(Sun) (Msub(Sun) - is the mass of the Sun)

  8. Simulation of polarimetric effects in planetary system HD 189733

    Science.gov (United States)

    Frantseva, K.; Kostogryz, N. M.; Yakobchuk, T. M.

    2012-11-01

    In this paper we present results of linear polarization modelling for HD 189733 in the U filter using the Monte Carlo method. Our simulations are based on the well known effect that linear polarization of a centrosymmetric unresolved star becomes non-zero during the planet transit or in the presence of spots on its surface. HD 189733 is currently the brightest (m_{V}=7.67^{m}) known star to harbour a transiting exoplanet. This fact, along with the short orbital period (2.2 d), makes it very suitable for different types of observations including polarimetry. Since we are interested in occultation effects, a very important parameter is the ratio of the planet to star radii, which is also very large (0.15). As the host star is active and spots may cover up to 1% of the planetary surface, we perform our simulations for different spot parameters such as sizes, locations on the stellar disk, and temperatures.

  9. Evidence for Quantisation in Planetary Ring Systems

    OpenAIRE

    WAYTE, RICHARD

    2017-01-01

    Absolute radial positions of the main features in Saturn's ring system have been calculated by adapting the quantum theory of atomic spectra. Fine rings superimposed upon broad rings are found to be covered by a harmonic series of the form N α A(r)1/2, where N and A are integers. Fourier analysis of the ring system shows that the spectral amplitude fits a response profile which is characteristic of a resonant system. Rings of Jupiter, Uranus and Neptune also obey the same rules. Involvement o...

  10. The NASA Planetary Data System Roadmap Study for 2017 - 2026

    Science.gov (United States)

    McNutt, R. L., Jr.; Gaddis, L. R.; Law, E.; Beyer, R. A.; Crombie, M. K.; Ebel, D. S. S.; Ghosh, A.; Grayzeck, E.; Morgan, T. H.; Paganelli, F.; Raugh, A.; Stein, T.; Tiscareno, M. S.; Weber, R. C.; Banks, M.; Powell, K.

    2017-12-01

    NASA's Planetary Data System (PDS) is the formal archive of >1.2 petabytes of data from planetary exploration, science, and research. Initiated in 1989 to address an overall lack of attention to mission data documentation, access, and archiving, the PDS has evolved into an online collection of digital data managed and served by a federation of six science discipline nodes and two technical support nodes. Several ad hoc mission-oriented data nodes also provide complex data interfaces and access for the duration of their missions. The recent Planetary Data System Roadmap Study for 2017 to 2026 involved 15 planetary science community members who collectively prepared a report summarizing the results of an intensive examination of the current state of the PDS and its organization, management, practices, and data holdings (https://pds.jpl.nasa.gov/roadmap/PlanetaryDataSystemRMS17-26_20jun17.pdf). The report summarizes the history of the PDS, its functions and characteristics, and how it has evolved to its present form; also included are extensive references and documentary appendices. The report recognizes that as a complex, evolving, archive system, the PDS must constantly respond to new pressures and opportunities. The report provides details on the challenges now facing the PDS, 19 detailed findings, suggested remediations, and a summary of what the future may hold for planetary data archiving. The findings cover topics such as user needs and expectations, data usability and discoverability (i.e., metadata, data access, documentation, and training), tools and file formats, use of current information technologies, and responses to increases in data volume, variety, complexity, and number of data providers. In addition, the study addresses the possibility of archiving software, laboratory data, and measurements of physical samples. Finally, the report discusses the current structure and governance of the PDS and its impact on how archive growth, technology, and new

  11. A Sample Delivery System for Planetary Missions

    Data.gov (United States)

    National Aeronautics and Space Administration — The project will develop, test and characterize the performance of a prototype /sample delivery system (SDS) implemented as an end effector on a robotic arm capable...

  12. A Planetary Park system for the Moon and beyond

    Science.gov (United States)

    Cockell, Charles; Horneck, Gerda

    Deutschland International space exploration programs foresee the establishment of human settlements on the Moon and on Mars within the next decades, following a series of robotic precursor missions. These increasing robotic visits and eventual human exploration and settlements may have an environmental impact on scientifically important sites and sites of natural beauty in the form of contamination with microorganisms and spacecraft parts, or even pollution as a consequence of in situ resource use. This concern has already been reflected in the Moon Treaty, "The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies" of the United Nations, which follows the Outer Space Treaty of the UN. However, so far, the Moon Treaty has not been ratified by any nation which engages in human space programs or has plans to do so. Planetary protection guidelines as formulated by the Committee on Space Research (COSPAR) are based on the Outer Space Treaty and follow the objectives: (i) to prevent contamination by terrestrial microorganisms if this might jeopardize scientific investi-gations of possible extraterrestrial life forms, and (ii) to protect the Earth from the potential hazard posed by extraterrestrial material brought back to the Earth. As a consequence, they group exploratory missions according to the type of mission and target body in five different categories, requesting specific means of cleaning and sterilization. However, the protection of extraterrestrial environments might also encompass ethical and other non-instrumental reasons. In order to allow intense scientific research and exploitation, and on the other hand to preserve regions of the Moon for research and use by future generations, we proposed the introduction of a planetary (or lunar) park system, which would protect areas of scientific, historic and intrinsic value under a common scheme. A similar placePlaceNamePlanetary PlaceTypePark system could be established on Mars well

  13. Planetary Sample Caching System Design Options

    Science.gov (United States)

    Collins, Curtis; Younse, Paulo; Backes, Paul

    2009-01-01

    Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.

  14. Searching for stable orbits in the HD 10180 planetary system

    Directory of Open Access Journals (Sweden)

    Laskar J.

    2011-02-01

    Full Text Available A planetary system with at least seven planets has been found around the star HD 10180. However, the traditional Keplerian and n-body fits to the data provide an orbital solution that becomes unstable very quickly, which may quest the reliability of the observations. Here we show that stable orbital configurations can be obtained if general relativity and long-term dissipation raised by tides on the innermost planet are taken into account.

  15. Orbital decay and accretion for planetary or binary systems within a planetary nebula

    International Nuclear Information System (INIS)

    Choi, K.H.

    1980-01-01

    The problem of the survival of a planet and low mass secondary orbiting a primary star that becomes a planetary nebula is studied. The values of the mass of primary used are 1.0, and 1.5, and 2.0 M/sub sun/ and the values for the planet's mass are 0.001 M/sub sun/ and 0.01 M/sub sun/. The mass of the secondary is 0.1 M/sub sun/. The evolution of the orbital elements and mass of the secondary due to accretion and drag forces in the common envelope are presented. The possible application of the results to V471 Tau, UU Sge, WZ Sge, and the sun-jupiter system are discussed

  16. THE IMPACT OF THE CONVECTIVE BLUESHIFT EFFECT ON SPECTROSCOPIC PLANETARY TRANSITS

    International Nuclear Information System (INIS)

    Shporer, Avi; Brown, Tim

    2011-01-01

    We present here a small anomalous radial velocity (RV) signal expected to be present in RV curves measured during planetary transits. This signal is induced by the convective blueshift (CB) effect-a net blueshift emanating from the stellar surface, resulting from a larger contribution of rising hot and bright gas relative to the colder and darker sinking gas. Since the CB radial component varies across the stellar surface, the light blocked by the planet during a transit will have a varying RV component, resulting in a small shift of the measured RVs. The CB-induced anomalous RV curve is different than, and independent of, the well-known Rossiter-McLaughlin (RM) effect, where the latter is used for determining the sky-projected angle between the host star rotation axis and the planet's orbital angular momentum axis. The observed RV curve is the sum of the CB and RM signals, and they are both superposed on the orbital Keplerian curve. If not accounted for, the presence of the CB RV signal in the spectroscopic transit RV curve may bias the estimate of the spin-orbit angle. In addition, future very high precision RVs will allow the use of transiting planets to study the CB of their host stars.

  17. Radial Velocity Detection of Extra-Solar Planetary Systems

    Science.gov (United States)

    Cochran, William D.

    2004-01-01

    This NASA Origins Program grant supported four closely related research programs at The University of Texas at Austin: 1) The McDonald Observatory Planetary Search (MOPS) Program, using the McDonald Observatory 2.7m Harlan Smith telescope and its 2dcoude spectrometer, 2) A high-precision radial-velocity survey of Hyades dwarfs, using the Keck telescope and its HIRES spectrograph, 3) A program at McDonald Observatory to obtain spectra of the parent stars of planetary systems at R = 210,000, and 4) the start of high precision radial velocity surveys using the Hobby-Eberly Telescope. The most important results from NASA support of these research programs are described. A list of all papers published under support of this grant is included at the end.

  18. Tandem planet formation for solar system-like planetary systems

    Directory of Open Access Journals (Sweden)

    Yusuke Imaeda

    2017-03-01

    Full Text Available We present a new united theory of planet formation, which includes magneto-rotational instability (MRI and porous aggregation of solid particles in a consistent way. We show that the “tandem planet formation” regime is likely to result in solar system-like planetary systems. In the tandem planet formation regime, planetesimals form at two distinct sites: the outer and inner edges of the MRI suppressed region. The former is likely to be the source of the outer gas giants, and the latter is the source for the inner volatile-free rocky planets. Our study spans disks with a various range of accretion rates, and we find that tandem planet formation can occur for M˙=10−7.3-10−6.9M⊙yr−1. The rocky planets form between 0.4–2 AU, while the icy planets form between 6–30 AU; no planets form in 2–6 AU region for any accretion rate. This is consistent with the gap in the solid component distribution in the solar system, which has only a relatively small Mars and a very small amount of material in the main asteroid belt from 2–6 AU. The tandem regime is consistent with the idea that the Earth was initially formed as a completely volatile-free planet. Water and other volatile elements came later through the accretion of icy material by occasional inward scattering from the outer regions. Reactions between reductive minerals, such as schreibersite (Fe3P, and water are essential to supply energy and nutrients for primitive life on Earth.

  19. STABILITY OF SATELLITES IN CLOSELY PACKED PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Payne, Matthew J.; Holman, Matthew J.; Deck, Katherine M.; Perets, Hagai B.

    2013-01-01

    We perform numerical integrations of four-body (star, planet, planet, satellite) systems to investigate the stability of satellites in planetary systems with tightly packed inner planets (STIPs). We find that the majority of closely spaced stable two-planet systems can stably support satellites across a range of parameter-space which is only slightly decreased compared to that seen for the single-planet case. In particular, circular prograde satellites remain stable out to ∼0.4 R H (where R H is the Hill radius) as opposed to 0.5 R H in the single-planet case. A similarly small restriction in the stable parameter-space for retrograde satellites is observed, where planetary close approaches in the range 2.5-4.5 mutual Hill radii destabilize most satellites orbits only if a ∼ 0.65 R H . In very close planetary pairs (e.g., the 12:11 resonance) the addition of a satellite frequently destabilizes the entire system, causing extreme close approaches and the loss of satellites over a range of circumplanetary semi-major axes. The majority of systems investigated stably harbored satellites over a wide parameter-space, suggesting that STIPs can generally offer a dynamically stable home for satellites, albeit with a slightly smaller stable parameter-space than the single-planet case. As we demonstrate that multi-planet systems are not a priori poor candidates for hosting satellites, future measurements of satellite occurrence rates in multi-planet systems versus single-planet systems could be used to constrain either satellite formation or past periods of strong dynamical interaction between planets

  20. 55 CANCRI: A COPLANAR PLANETARY SYSTEM THAT IS LIKELY MISALIGNED WITH ITS STAR

    International Nuclear Information System (INIS)

    Kaib, Nathan A.; Duncan, Martin J.; Raymond, Sean N.

    2011-01-01

    Although the 55 Cnc system contains multiple, closely packed planets that are presumably in a coplanar configuration, we use numerical simulations to demonstrate that they are likely to be highly inclined to their parent star's spin axis. Due to perturbations from its distant binary companion, this planetary system precesses like a rigid body about its parent star. Consequently, the parent star's spin axis and the planetary orbit normal likely diverged long ago. Because only the projected separation of the binary is known, we study this effect statistically, assuming an isotropic distribution for wide binary orbits. We find that the most likely projected spin-orbit angle is ∼50°, with a ∼30% chance of a retrograde configuration. Transit observations of the innermost planet—55 Cnc e—may be used to verify these findings via the Rossiter-McLaughlin effect. 55 Cancri may thus represent a new class of planetary systems with well-ordered, coplanar orbits that are inclined with respect to the stellar equator.

  1. TRAPPIST: a robotic telescope dedicated to the study of planetary systems

    Directory of Open Access Journals (Sweden)

    Manfroid J.

    2011-02-01

    Full Text Available We present here a new robotic telescope called TRAPPIST1 (TRAnsiting Planets and PlanetesImals Small Telescope. Equipped with a high-quality CCD camera mounted on a 0.6 meter light weight optical tube, TRAPPIST has been installed in April 2010 at the ESO La Silla Observatory (Chile, and is now beginning its scientific program. The science goal of TRAPPIST is the study of planetary systems through two approaches: the detection and study of exoplanets, and the study of comets. We describe here the objectives of the project, the hardware, and we present some of the first results obtained during the commissioning phase.

  2. Conceptual definition of Automated Power Systems Management. [for planetary spacecraft

    Science.gov (United States)

    Imamura, M. S.; Skelly, L.; Weiner, H.

    1977-01-01

    Automated Power Systems Management (APSM) is defined as the capability of a spacecraft power system to automatically perform monitoring, computational, command, and control functions without ground intervention. Power systems for future planetary spacecraft must have this capability because they must perform up to 10 years, and accommodate real-time changes in mission execution autonomously. Specific APSM functions include fault detection, isolation, and correction; system performance and load profile prediction; power system optimization; system checkout; and data storage and transmission control. This paper describes the basic method of implementing these specific functions. The APSM hardware includes a central power system computer and a processor dedicated to each major power system subassembly along with digital interface circuitry. The major payoffs anticipated are in enhancement of spacecraft reliability and life and reduction of overall spacecraft program cost.

  3. A search for extra-solar planetary transits in the field of open cluster NGC 6819

    Science.gov (United States)

    Street, Rachel Amanda

    The technique of searching for extra-solar planetary transits is investigated. This technique, which relies on detecting the brief, shallow eclipses caused by planets passing across the line of sight to the primary star, requires high-precision time-series photometry of large numbers of stars in order to detect these statistically rare events. Observations of 18000 stars in the field including the intermediate-age open cluster NGC 6819 are presented. This target field constrasts with the stellar environment surveyed by the radial velocity technique, which concentrates on the Solar neighbourhood. I present the data-reduction techniques used to obtain high-precision photometry in a semi-automated fashion for tens of thousands of stars at a time, together with an algorithm designed to search the resulting lightcurves for the transit signatures of hot Jupiter type planets. I describe simulations designed to test the detection efficiency of this algorithm and, for comparison, predict the number of transits expected from this data, assuming that hot Jupiter planets similar to HD 209458 are as common in the field of NGC 6819 as they are in the Solar neighbourhood. While no planetary transits have yet been identified, the detection of several very low amplitude eclipses by stellar companions demonstrates the effectiveness of the method. This study also indicates that stellar activity and particularly blending are significant causes of false detections. A useful additional consequence of studying this time-series photometry is the census it provides of some of the variable stars in the field. I report on the discovery of a variety of newly-discovered variables, including Algol-type detached eclipsing binaries which are likely to consist of M-dwarf stars. Further study of these stars is strongly recommended in order to help constrain models of stellar structure at the very low mass end. I conclude with a summary of this work in the context of other efforts being made in this

  4. PLANET-PLANET SCATTERING LEADS TO TIGHTLY PACKED PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

    2009-01-01

    The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masses, the mass-inclination degeneracy does not significantly affect our results. We consider a wide range of initial planetary mass distributions and find that some are poor fits to the observed systems. In fact, many of our scattering experiments overproduce systems very close to the stability boundary. The distribution of dynamical configurations of two-planet systems may provide better discrimination between scattering models than the distribution of eccentricity. Our results imply that, at least in their inner regions which are weakly affected by gas or planetesimal disks, planetary systems should be 'packed', with no large gaps between planets.

  5. A review of the scientific rationale and methods used in the search for other planetary systems

    Science.gov (United States)

    Black, D. C.

    1985-01-01

    Planetary systems appear to be one of the crucial links in the chain leading from simple molecules to living systems, particularly complex (intelligent?) living systems. Although there is currently no observational proof of the existence of any planetary system other than our own, techniques are now being developed which will permit a comprehensive search for other planetary systems. The scientific rationale for and methods used in such a search effort are reviewed here.

  6. Energy systems in transition

    International Nuclear Information System (INIS)

    Haefele, W.

    1989-01-01

    The principal point of the author was to discuss energy systems (ES) in transition, transition addresses the next 10-25 years, and strategy of the transition. He considers different scenarios of future development of ES. Further he presents considerations elaborated during the last years on the concept of novel horizontally integrated ES which gives promise to be at least an approximation to the desired object of no emissions. The main ideas of the concept are: to decompose and thereby clean all the primary inputs before they are brought to combustion; to develop a network combining all the primary inputs to an integrated supply structure of high absorption, buffer, and storage capacity that resembles in some way the supply and utility functions of the well established electric grid but completes it at best on the basis of mass flows; to achieve a high flexibility in supplying the final energy. The author considers the long run perspective of hydrogen, solar, and nuclear energy with respect to alternative energy sources. 6 refs, 24 figs

  7. Electrohydraulic drive system with planetary superposed PS 16 gears

    Energy Technology Data Exchange (ETDEWEB)

    Graetz, A.; Klimek, K.H.; Welz, H.

    1988-10-20

    During the nine-month period of use of the electrohydraulic drive system with PS 16 superposed planetary gear and hydrostatic support advance of 800 m was achieved on the 250 m long face in the Geitling 2 seam at the Niederberg colliery. No appreciable difficulties occurred in the hydraulic system and with the PS 16 superposed planetary gear in the entire period. Uniform load distribution between the two drives was proved until the end of the working even with a chain elongation difference up to 3% observed during the final phase of operation. In contrast to normal operation thermal disconnections and motor failures no longer occurred. After accurate adjustment of the pressures the system operated successfully. The time utilisation of the equipment was improved by 15% to 65.7%. The quick and reliable response of the hydraulics in the event of overloading ensured that no chain cracks occurred. The four connector fractures were attributable to fatigue failures. The material-protecting method of operation was proved by the quiet running of the chain and substantially longer operating time, e.g. of the chain and sprocket. To prove the efficiency of the new drive system, comprehensive measurements were undertaken. It emerged during these measurements that in contrast to the conventional drives the load equalisation ensures that the total installed power is available if required. However, the freeing capacity of the plough could not be fully utilised because of the missing conveyor cross-section.

  8. Journal Bearing Analysis Suite Released for Planetary Gear System Evaluation

    Science.gov (United States)

    Brewe, David E.; Clark, David A.

    2005-01-01

    Planetary gear systems are an efficient means of achieving high reduction ratios with minimum space and weight. They are used in helicopter, aerospace, automobile, and many industrial applications. High-speed planetary gear systems will have significant dynamic loading and high heat generation. Hence, they need jet lubrication and associated cooling systems. For units operating in critical applications that necessitate high reliability and long life, that have very large torque loading, and that have downtime costs that are significantly greater than the initial cost, hydrodynamic journal bearings are a must. Computational and analytical tools are needed for sufficiently accurate modeling to facilitate optimal design of these systems. Sufficient physics is needed in the model to facilitate parametric studies of design conditions that enable optimal designs. The first transient journal bearing code to implement the Jacobsson-Floberg-Olsson boundary conditions, using a mass-conserving algorithm devised by Professor Emeritus Harold Elrod of Columbia University, was written by David E. Brewe of the U.S. Army at the NASA Lewis Research Center1 in 1983. Since then, new features and improved modifications have been built into the code by several contributors supported through Army and NASA funding via cooperative agreements with the University of Toledo (Professor Ted Keith, Jr., and Dr. Desikakary Vijayaraghavan) and National Research Council Programs (Dr. Vijayaraghavan). All this was conducted with the close consultation of Professor Elrod and the project management of David Brewe.

  9. PLANETARY CONSTRUCTION ZONES IN OCCULTATION: DISCOVERY OF AN EXTRASOLAR RING SYSTEM TRANSITING A YOUNG SUN-LIKE STAR AND FUTURE PROSPECTS FOR DETECTING ECLIPSES BY CIRCUMSECONDARY AND CIRCUMPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Mamajek, Eric E.; Quillen, Alice C.; Pecaut, Mark J.; Moolekamp, Fred; Scott, Erin L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Kenworthy, Matthew A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Cameron, Andrew Collier; Parley, Neil R. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2012-03-15

    estimated total ring mass is {approx}8-0.4 M{sub Moon} (if the rings have optical opacity similar to Saturn's rings), and the edge of the outermost detected ring has orbital radius {approx}0.4-0.09 AU. In the new era of time-domain astronomy opened by surveys like SuperWASP, ASAS, etc., and soon to be revolutionized by Large Synoptic Survey Telescope, discovering and characterizing eclipses by circumplanetary and circumsecondary disks will provide us with observational constraints on the conditions that spawn satellite systems around gas giant planets and planetary systems around stars.

  10. Planets and planetarians. A history of theories of the origin of planetary systems

    Energy Technology Data Exchange (ETDEWEB)

    Jaki, S L

    1978-01-01

    A critical review is presented of theories of the origin of planetary systems. The book deals chronologically with the subject from Greek times to the present. The last of the eight chapters covers the post-war period. Particular attention is paid to theories of the origin of our own planetary system and to the degree of frequency of planetary systems (in particular, the frequency of planets carrying life in some form) in the universe.

  11. Planets and planetarians. A history of theories of the origin of planetary systems

    International Nuclear Information System (INIS)

    Jaki, S.L.

    1978-01-01

    A critical review is presented of theories of the origin of planetary systems. The book deals chronologically with the subject from Greek times to the present. The last of the eight chapters covers the post-war period. Particular attention is paid to theories of the origin of our own planetary system and to the degree of frequency of planetary systems (in particular, the frequency of planets carrying life in some form) in the universe. (U.K.)

  12. Nonlinear Vibroimpact Characteristics of a Planetary Gear Transmission System

    Directory of Open Access Journals (Sweden)

    Jianxing Zhou

    2016-01-01

    Full Text Available In order to research the vibroimpact characteristics of a planetary gear transmission system under high speed and lightly loaded conditions, a new modeling method is proposed. In the modeling process, linear spring was used to simulate gear mesh elasticity under heavy load cases, and Hertz contact theory was used to calculate the contact force of gear pair under light load cases. Then, effects of the working conditions on the system vibroimpact characteristics are analyzed. The results show that, with input speed growing, the mesh force produced obvious fluctuations on the resonance frequencies of the sun gear and carrier torsion vibration, ring gear’s transverse vibration under the heavy load. Under light load condition, the collision vibration occurs in the gear pair; the changing trend of the contact force shows strongly nonlinear characteristics. The time of mesh-apart in gears pair decreases gradually as the load is increased; until it reaches collision vibration threshold value, the gear pair is no longer mesh-apart. With increasing of the input speed, the time of mesh-apart is decreased gradually; the fluctuation amplitude of contact force shows a linearly increasing trend. The study provides useful theoretical guideline for planetary gear transmission low-noise design.

  13. Environmental Control and Life Support Systems for Mars Exploration: Issues and Concerns for Planetary Protection and the Protection of Science

    Science.gov (United States)

    Barta, Daniel J.; Lange, Kevin; Anderson, Molly; Vonau, Walter

    2016-07-01

    Planetary protection represents an additional set of requirements that generally have not been considered by developers of technologies for Environmental Control and Life Support Systems (ECLSS). Forward contamination concerns will affect release of gases and discharge of liquids and solids, including what may be left behind after planetary vehicles are abandoned upon return to Earth. A crew of four using a state of the art ECLSS could generate as much as 4.3 metric tons of gaseous, liquid and solid wastes and trash during a 500-day surface stay. These may present issues and concerns for both planetary protection and planetary science. Certainly, further closure of ECLSS systems will be of benefit by greater reuse of consumable products and reduced generation of waste products. It can be presumed that planetary protection will affect technology development by constraining how technologies can operate: limiting or prohibiting certain kinds of operations or processes (e.g. venting); necessitating that other kinds of operations be performed (e.g. sterilization; filtration of vent lines); prohibiting what can be brought on a mission (e.g. extremophiles); creating needs for new capabilities/ technologies (e.g. containment). Although any planned venting could include filtration to eliminate micro-organisms from inadvertently exiting the spacecraft, it may be impossible to eliminate or filter habitat structural leakage. Filtration will add pressure drops impacting size of lines and ducts, affect fan size and energy requirements, and add consumable mass. Technologies that may be employed to remove biomarkers and microbial contamination from liquid and solid wastes prior to storage or release may include mineralization technologies such as incineration, super critical wet oxidation and pyrolysis. These technologies, however, come with significant penalties for mass, power and consumables. This paper will estimate the nature and amounts of materials generated during Mars

  14. The planetary data system educational CD-ROM

    Science.gov (United States)

    Guinness, E. A.; Arvidson, R. E.; Martin, M.; Dueck, S.

    1993-01-01

    The Planetary Data System (PDS) is producing a special educational CD-ROM that contains samples of PDS datasets and is expected to be released in 1993. The CD-ROM will provide university-level instructors with PDS-compatible materials and information that can be used to construct student problem sets using real datasets. The main purposes of the CD-ROM are to facilitate wide use of planetary data and to introduce a large community to the PDS. To meet these objectives the Educational CD-ROM will also contain software to manipulate the data, background discussions about scientific questions that can be addressed with the data, and a suite of exercises that illustrate analysis techniques. Students will also be introduced to the SPICE concept, which is a new way of maintaining geometry and instrument information. The exercises will be presented at the freshman through graduate student levels. With simplification, some of the material should also be of use at the high school level.

  15. An archiving system for Planetary Mapping Data - Availability of derived information and knowledge in Planetary Science!

    Science.gov (United States)

    Nass, A.

    2017-12-01

    Since the late 1950s a huge number of planetary missions started to explore our solar system. The data resulting from this robotic exploration and remote sensing varies in data type, resolution and target. After data preprocessing, and referencing, the released data are available for the community on different portals and archiving systems, e.g. PDS or PSA. One major usage for these data is mapping, i.e. the extraction and filtering of information by combining and visualizing different kind of base data. Mapping itself is conducted either for mission planning (e.g. identification of landing site) or fundamental research (e.g. reconstruction of surface). The mapping results for mission planning are directly managed within the mission teams. The derived data for fundamental research - also describable as maps, diagrams, or analysis results - are mainly project-based and exclusively available in scientific papers. Within the last year, first steps have been taken to ensure a sustainable use of these derived data by finding an archiving system comparable to the data portals, i.e. reusable, well-documented, and sustainable. For the implementation three tasks are essential. Two tasks have been treated in the past 1. Comparability and interoperability has been made possible by standardized recommendations for visual, textual, and structural description of mapping data. 2. Interoperability between users, information- and graphic systems is possible by templates and guidelines for digital GIS-based mapping. These two steps are adapted e.g. within recent mapping projects for the Dawn mission. The third task hasn`t been implemented thus far: Establishing an easily detectable and accessible platform that holds already acquired information and published mapping results for future investigations or mapping projects. An archive like this would support the scientific community significantly by a constant rise of knowledge and understanding based on recent discussions within

  16. Machine Learning Algorithms For Predicting the Instability Timescales of Compact Planetary Systems

    Science.gov (United States)

    Tamayo, Daniel; Ali-Dib, Mohamad; Cloutier, Ryan; Huang, Chelsea; Van Laerhoven, Christa L.; Leblanc, Rejean; Menou, Kristen; Murray, Norman; Obertas, Alysa; Paradise, Adiv; Petrovich, Cristobal; Rachkov, Aleksandar; Rein, Hanno; Silburt, Ari; Tacik, Nick; Valencia, Diana

    2016-10-01

    The Kepler mission has uncovered hundreds of compact multi-planet systems. The dynamical pathways to instability in these compact systems and their associated timescales are not well understood theoretically. However, long-term stability is often used as a constraint to narrow down the space of orbital solutions from the transit data. This requires a large suite of N-body integrations that can each take several weeks to complete. This computational bottleneck is therefore an important limitation in our ability to characterize compact multi-planet systems.From suites of numerical simulations, previous studies have fit simple scaling relations between the instability timescale and various system parameters. However, the numerically simulated systems can deviate strongly from these empirical fits.We present a new approach to the problem using machine learning algorithms that have enjoyed success across a broad range of high-dimensional industry applications. In particular, we have generated large training sets of direct N-body integrations of synthetic compact planetary systems to train several regression models (support vector machine, gradient boost) that predict the instability timescale. We find that ensembling these models predicts the instability timescale of planetary systems better than previous approaches using the simple scaling relations mentioned above.Finally, we will discuss how these models provide a powerful tool for not only understanding the current Kepler multi-planet sample, but also for characterizing and shaping the radial-velocity follow-up strategies of multi-planet systems from the upcoming Transiting Exoplanet Survey Satellite (TESS) mission, given its shorter observation baselines.

  17. Multi-Planetary Systems: Observations and Models of Dynamical Interactions

    Science.gov (United States)

    Lissauer, Jack J.

    2018-01-01

    More than 600 multi-planet systems are known. The vast majority of these systems have been discovered by NASA's Kepler spacecraft, but dozens were found using the Doppler technique, the first multi-exoplanet system was identified through pulsar timing, and the most massive system has been found using imaging. More than one-third of the 4000+ planet candidates found by NASA's Kepler spacecraft are associated with target stars that have more than one planet candidate, and the large number of such Kepler "multis" tells us that flat multiplanet systems like our Solar System are common. Virtually all of Kepler candidate multis are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship. Statistical studies performed on these candidate systems reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness. The characteristics of several of the most interesting confirmed multi-exoplanet systems will also be discussed.HR 8799's four massive planets orbit tens of AU from their host star and travel on nearly circular orbits. PSR B1257+12 has three much smaller planets orbiting close to a neutron star. Both represent extremes and show that planet formation is a robust process that produces a diversity of outcomes. Although both exomoons and Trojan (triangle Lagrange point) planets have been searched for, neither has yet been found.

  18. Enviromnental Control and Life Support Systems for Mars Missions - Issues and Concerns for Planetary Protection

    Science.gov (United States)

    Barta, Daniel J.; Anderson, Molly S.; Lange, Kevin

    2015-01-01

    Planetary protection represents an additional set of requirements that generally have not been considered by developers of technologies for Environmental Control and Life Support Systems (ECLSS). Planetary protection guidelines will affect the kind of operations, processes, and functions that can take place during future human planetary exploration missions. Ultimately, there will be an effect on mission costs, including the mission trade space when planetary protection requirements begin to drive vehicle deisgn in a concrete way. Planetary protection requirements need to be considered early in technology development and mission programs in order to estimate these impacts and push back on requirements or find efficient ways to perform necessary functions. It is expected that planetary protection will be a significant factor during technology selection and system architecture design for future missions.

  19. Utilizing a scale model solar system project to visualize important planetary science concepts and develop technology and spatial reasoning skills

    Science.gov (United States)

    Kortenkamp, Stephen J.; Brock, Laci

    2016-10-01

    Scale model solar systems have been used for centuries to help educate young students and the public about the vastness of space and the relative sizes of objects. We have adapted the classic scale model solar system activity into a student-driven project for an undergraduate general education astronomy course at the University of Arizona. Students are challenged to construct and use their three dimensional models to demonstrate an understanding of numerous concepts in planetary science, including: 1) planetary obliquities, eccentricities, inclinations; 2) phases and eclipses; 3) planetary transits; 4) asteroid sizes, numbers, and distributions; 5) giant planet satellite and ring systems; 6) the Pluto system and Kuiper belt; 7) the extent of space travel by humans and robotic spacecraft; 8) the diversity of extrasolar planetary systems. Secondary objectives of the project allow students to develop better spatial reasoning skills and gain familiarity with technology such as Excel formulas, smart-phone photography, and audio/video editing.During our presentation we will distribute a formal description of the project and discuss our expectations of the students as well as present selected highlights from preliminary submissions.

  20. Evolution of Planetary Ice-Ocean Systems: Effects of Salinity

    Science.gov (United States)

    Allu Peddinti, D.; McNamara, A. K.

    2015-12-01

    Planetary oceanography is enjoying renewed attention thanks to not only the detection of several exoplanetary ocean worlds but also due to the expanding family of ocean worlds within our own star system. Our solar system is now believed to host about nine ocean worlds including Earth, some dwarf planets and few moons of Jupiter and Saturn. Amongst them, Europa, like Earth is thought to have an ice Ih-liquid water system. However, the thickness of the Europan ice-ocean system is much larger than that of the Earth. The evolution of this system would determine the individual thicknesses of the ice shell and the ocean. In turn, these thicknesses can alter the course of evolution of the system. In a pure H2O system, the thickness of the ice shell would govern if heat loss occurs entirely by conduction or if the shell begins to convect as it attains a threshold thickness. This switch between conduction-convection regimes could determine the longevity of the subsurface ocean and hence define the astrobiological potential of the planetary body at any given time. In reality, however, the system is not pure water ice. The detected induced magnetic field infers a saline ocean layer. Salts are expected to act as an anti-freeze allowing a subsurface ocean to persist over long periods but the amount of salts would determine the extent of that effect. In our current study, we use geodynamic models to examine the effect of salinity on the evolution of ice-ocean system. An initial ocean with different salinities is allowed to evolve. The effect of salinity on thickness of the two layers at any time is examined. We also track how salinity controls the switch between conductive-convective modes. The study shows that for a given time period, larger salinities can maintain a thick vigorously convecting ocean while the smaller salinities behave similar to a pure H2O system leading to a thick convecting ice-shell. A range of salinities identified can potentially predict the current state

  1. Detecting and Interpreting the Dynamical Evolution of Transiting Multiplanet Systems

    Science.gov (United States)

    Mills, Sean Martin

    The dynamical interactions of our Solar System have been studied in depth since Isaac Newton recognized that the planets may not be stable to each other's gravitational perturbations. Recently, the discovery of exoplanet systems, including approximately a thousand planet candidates in systems of more than two bodies, has opened an extremely vast and diverse laboratory for planetary dynamics. In this dissertation, I describe techniques for measuring the dynamical, post-Keplerian interactions of planetary systems. Such signals often require numerical N-body analysis and photodynamic techniques combined with Bayesian statistics to correctly determine the properties of the planetary systems causing them. By simultaneously fitting the entire lightcurve data set at once, I am able to extract low signal-to-noise effects such as the resonance dynamics of a very faint system (Kepler-223), the slow orbital precession of a giant planet system (Kepler-108), and transit timing variations among very small and low mass planets (Kepler-444). I use these analyses to gain physical insight into the system's history, such as Kepler-108's potentially chaotic, violent past. Kepler-223's present structure indicates a migration origin for at least some close-in, sub-Neptune planets, which I explore in terms of tidal dissipation, smooth and stochastic migration, and secular evolution. I also analyze circumbinary systems including the newly discovered KIC 10753734. Taken together, these results provide insight into planetary formation in a broad array of environments for planet from compact sub-Neptune systems to Jupiters and circumbinary planets.

  2. TRANSIT MODEL OF PLANETS WITH MOON AND RING SYSTEMS

    International Nuclear Information System (INIS)

    Tusnski, Luis Ricardo M.; Valio, Adriana

    2011-01-01

    Since the discovery of the first exoplanets, those most adequate for life to begin and evolve have been sought. Due to observational bias, however, most of the discovered planets so far are gas giants, precluding their habitability. However, if these hot Jupiters are located in the habitable zones of their host stars, and if rocky moons orbit them, then these moons may be habitable. In this work, we present a model for planetary transit simulation considering the presence of moons and planetary rings around a planet. The moon's orbit is considered to be circular and coplanar with the planetary orbit. The other physical and orbital parameters of the star, planet, moon, and rings can be adjusted in each simulation. It is possible to simulate as many successive transits as desired. Since the presence of spots on the surface of the star may produce a signal similar to that of the presence of a moon, our model also allows for the inclusion of starspots. The result of the simulation is a light curve with a planetary transit. White noise may also be added to the light curves to produce curves similar to those obtained by the CoRoT and Kepler space telescopes. The goal is to determine the criteria for detectability of moons and/or ring systems using photometry. The results show that it is possible to detect moons with radii as little as 1.3 R ⊕ with CoRoT and 0.3 R ⊕ with Kepler.

  3. Agriculture production as a major driver of the earth system exceeding planetary boundaries

    DEFF Research Database (Denmark)

    Campbell, Bruce Morgan; Beare, Douglas J.; Bennett, Elena M.

    2017-01-01

    We explore the role of agriculture in destabilizing the Earth system at the planetary scale, through examining nine planetary boundaries, or “safe limits”: land-system change, freshwater use, biogeochemical flows, biosphere integrity, climate change, ocean acidification, stratospheric ozone...

  4. Planetary Radar

    Science.gov (United States)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

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

  5. From red giants to planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1982-01-01

    The transition from red giants to planetary nebulae is studied by comparing the spectral characteristics of red giant envelopes and planetary nebulae. Observational and theoretical evidence both suggest that remnants of red giant envelopes may still be present in planetary nebula systems and should have significant effects on their formation. The dynamical effects of the interaction of stellar winds from central stars of planetary nebulae with the remnant red giant envelopes are evaluated and the mechanism found to be capable of producing the observed masses and momenta of planetary nebulae. The observed mass-radii relation of planetary nebulae may also be best explained by the interacting winds model. The possibility that red giant mass loss, and therefore the production of planetary nebulae, is different between Population I and II systems is also discussed

  6. Agriculture production as a major driver of the Earth system exceeding planetary boundaries

    Directory of Open Access Journals (Sweden)

    Bruce M. Campbell

    2017-12-01

    Full Text Available We explore the role of agriculture in destabilizing the Earth system at the planetary scale, through examining nine planetary boundaries, or "safe limits": land-system change, freshwater use, biogeochemical flows, biosphere integrity, climate change, ocean acidification, stratospheric ozone depletion, atmospheric aerosol loading, and introduction of novel entities. Two planetary boundaries have been fully transgressed, i.e., are at high risk, biosphere integrity and biogeochemical flows, and agriculture has been the major driver of the transgression. Three are in a zone of uncertainty i.e., at increasing risk, with agriculture the major driver of two of those, land-system change and freshwater use, and a significant contributor to the third, climate change. Agriculture is also a significant or major contributor to change for many of those planetary boundaries still in the safe zone. To reduce the role of agriculture in transgressing planetary boundaries, many interventions will be needed, including those in broader food systems.

  7. Transits of planets with small intervals in circumbinary systems

    International Nuclear Information System (INIS)

    Liu, Hui-Gen; Wang, Ying; Zhang, Hui; Zhou, Ji-Lin

    2014-01-01

    Transit times around single stars can be described well by a linear ephemeris. However, transit times in circumbinary systems are influenced both by the gravitational perturbations and the orbital phase variations of the central binary star. Adopting a coplanar analog of Kepler-16 as an example, we find that circumbinary planets can transit the same star more than once during a single planetary orbit, a phenomenon we call 'tight transits.' In certain geometric architecture, the projected orbital velocity of the planet and the secondary star can approach zero and change sign, resulting in very long transits and/or 2-3 transits during a single binary orbit. Whether tight transits are possible for a particular system depends primarily on the binary mass ratio and the orbital architecture of both the binary and the planet. We derive a time-dependent criterion to judge when tight transits are possible for any circumbinary system. These results are verified with full dynamical integrations that also reveal other tight transit characteristics, i.e., the transit durations and the intervals between tight transits. For the seven currently known circumbinary systems, we estimate these critical parameters both analytically and numerically. Due to the mutual inclination between the planet and the binary, tight transits can only occur across the less massive star B in Kepler-16, -34, -35, and -47 (for both planets). The long-term average frequency of tight transits (compared to typical transits) for Kepler-16, -34, and -35 are estimated to be several percent. Using full numerical integrations, the next tight transit for each system is predicted and the soonest example appears to be Kepler-47b and -47c, which are likely to have tight transits before 2025. These unique and valuable events often deserve special observational scrutiny.

  8. Cryogenic and LOX Based Propulsion Systems for Robotic Planetary Missions

    National Research Council Canada - National Science Library

    Valentian, Dominique

    2005-01-01

    Robotic planetary missions use almost exclusively storable propellants. However, it is clear that the use LOX/LH2 and LOX/HC combinations will offer a tremendous payload gain for most robotic missions...

  9. A new dataset validation system for the Planetary Science Archive

    Science.gov (United States)

    Manaud, N.; Zender, J.; Heather, D.; Martinez, S.

    2007-08-01

    The Planetary Science Archive is the official archive for the Mars Express mission. It has received its first data by the end of 2004. These data are delivered by the PI teams to the PSA team as datasets, which are formatted conform to the Planetary Data System (PDS). The PI teams are responsible for analyzing and calibrating the instrument data as well as the production of reduced and calibrated data. They are also responsible of the scientific validation of these data. ESA is responsible of the long-term data archiving and distribution to the scientific community and must ensure, in this regard, that all archived products meet quality. To do so, an archive peer-review is used to control the quality of the Mars Express science data archiving process. However a full validation of its content is missing. An independent review board recently recommended that the completeness of the archive as well as the consistency of the delivered data should be validated following well-defined procedures. A new validation software tool is being developed to complete the overall data quality control system functionality. This new tool aims to improve the quality of data and services provided to the scientific community through the PSA, and shall allow to track anomalies in and to control the completeness of datasets. It shall ensure that the PSA end-users: (1) can rely on the result of their queries, (2) will get data products that are suitable for scientific analysis, (3) can find all science data acquired during a mission. We defined dataset validation as the verification and assessment process to check the dataset content against pre-defined top-level criteria, which represent the general characteristics of good quality datasets. The dataset content that is checked includes the data and all types of information that are essential in the process of deriving scientific results and those interfacing with the PSA database. The validation software tool is a multi-mission tool that

  10. Distribution of mass in the planetary system and solar nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Weidenschilling, S J [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

    1977-09-01

    A model 'solar nebula' is constructed by adding the solar complement of light elements to each planet, using recent models of planetary compositions. Uncertainties in this approach are estimated. The computed surface density varies approximately as rsup(-3/2). Mercury, Mars and the asteroid belt are anomalously low in mass, but processes exist which would preferentially remove matter from these regions. Planetary masses and compositions are generally consistent with a monotonic density distribution in the primordial solar nebula.

  11. NIRCam Coronagraphic Observations of Disks and Planetary Systems

    Science.gov (United States)

    Beichman, Charles A.; Ygouf, Marie; Gaspar, Andras; NIRCam Science Team

    2017-06-01

    The NIRCam coronagraph offers a dramatic increase in sensitivity at wavelengths of 3-5 um where young planets are brightest. While large ground-based telescopes with Extreme Adaptive Optics have an advantage in inner working angle, NIRCam's sensitivity will allow high precision photometry for known planets and searches for planets with masses below that of Saturn. For debris disk science NIRCam observations will address the scattering properties of dust, look for evidence of ices and tholins, and search for planets which affect the structure of the disk itself.The NIRCam team's GTO program includes medium-band filter observations of known young planets having 1-5 Jupiter masses. A collaborative program with the MIRI team will provide coronagraphic observations at longer wavelengths. The combined dataset will yield the exoplanet’s total luminosity and effective temperature, an estimate of the initial entropy of the newly-formed planet, and the retrieval of atmospheric properties.The program will also make deep searches for lower mass planets toward known planetary systems, nearby young M stars and debris disk systems. Achievable mass limits range from ~1 Jupiter mass beyond 20 AU for the brightest A stars to perhaps a Uranus mass within 10 AU for the closest M stars.We will discuss details of the coronagraphic program for both the exoplanet and debris disk cases with an emphasis on using APT to optimize the observations of target and reference stars.

  12. Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Fabrycky, Daniel C.; /Lick Observ.; Ford, Eric B.; /Florida U.; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Welsh, William F.; /Caltech; Borucki, William J.; /NASA, Ames /UC, Santa Barbara

    2012-01-01

    We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anticorrelations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems, Kepler-25, Kepler-26, Kepler-27 and Kepler-28, containing eight planets and one additional planet candidate.

  13. Reviews in Modern Astronomy: Vol. 17: The Sun and Planetary Systems - Paradigms for the Universe

    Science.gov (United States)

    Schielicke, Reinhard E.

    2004-09-01

    Volume 17 continues the Reviews of Modern Astronomy with fourteen invited reviews and Highlight Contributions which were presented during the International Scientific Conference of the Society on "The Sun and Planetary Systems", held at Freiburg, Germany, September 15 to 20, 2003. The Karl Schwarzschild medal 2003 was awarded to Professor Erika Boehm-Vitense, Seattle, USA. Her lecture with the title "What Hyades F Stars tell us about Heating Mechanisms in Stellar Transition Layers and Coronae" opened the meeting. The talk presented by the Ludwig Biermann-Prize winner 2003, Dr Luis R. Bellot Rubio, Freiburg i. Br., Germany, dealt with the topic "The Structure of Sunspots as Inferred from Spectropolarimetric Measurements". Other contributions to the meeting published in this volume discuss, among other subjects, solar physics, formation of planets and interferometric imaging in astronomy.

  14. Phase transition in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

    2000-01-01

    In this paper we present a review of selected aspects of Phase transitions in finite systems applied in particular to the liquid-gas phase transition in nuclei. We show that the problem of the non existence of boundary conditions can be solved by introducing a statistical ensemble with an averaged constrained volume. In such an ensemble the microcanonical heat capacity becomes negative in the transition region. We show that the caloric curve explicitly depends on the considered transformation of the volume with the excitation energy and so does not bear direct informations on the characteristics of the phase transition. Conversely, partial energy fluctuations are demonstrated to be a direct measure of the equation of state. Since the heat capacity has a negative branch in the phase transition region, the presence of abnormally large kinetic energy fluctuations is a signal of the liquid gas phase transition. (author)

  15. Where can a Trappist-1 planetary system be produced?

    Science.gov (United States)

    Haworth, Thomas J.; Facchini, Stefano; Clarke, Cathie J.; Mohanty, Subhanjoy

    2018-04-01

    We study the evolution of protoplanetary discs that would have been precursors of a Trappist-1-like system under the action of accretion and external photoevaporation in different radiation environments. Dust grains swiftly grow above the critical size below which they are entrained in the photoevaporative wind, so although gas is continually depleted, dust is resilient to photoevaporation after only a short time. This means that the ratio of the mass in solids (dust plus planetary) to the mass in gas rises steadily over time. Dust is still stripped early on, and the initial disc mass required to produce the observed 4 M⊕ of Trappist-1 planets is high. For example, assuming a Fatuzzo & Adams distribution of UV fields, typical initial disc masses have to be >30 per cent the stellar (which are still Toomre Q stable) for the majority of similar mass M dwarfs to be viable hosts of the Trappist-1 planets. Even in the case of the lowest UV environments observed, there is a strong loss of dust due to photoevaporation at early times from the weakly bound outer regions of the disc. This minimum level of dust loss is a factor of 2 higher than that which would be lost by accretion on to the star during 10 Myr of evolution. Consequently, even in these least irradiated environments, discs that are viable Trappist-1 precursors need to be initially massive (>10 per cent of the stellar mass).

  16. Magnetism, planetary rotation and convection in the solar system

    CERN Document Server

    1985-01-01

    On the 6th, 7th' and 8th April 1983, a conference entitled "Magnetism, planetary rotation and convection in the Solar System" was held in the School of Physics at the University of Newcastle upon Tyne. The purpose of the meeting was to celebrate the 60th birthday of Prof. Stanley Keith Runcorn and his, and his students' and associates', several decades of scientific achievement. The social programme, which consisted of excursions in Northumberland and Durham with visits to ancient castles and churches, to Hexham Abbey and Durham Cathedral, and dinners in Newcastle and Durham, was greatly enjoyed by those attending the meeting and by their guests. The success ofthe scientific programme can be judged by this special edition of Geophysical Surveys which is derived mainly from the papers given at the meeting. The story starts in the late 1940s when the question of the origin of the magnetic field of the Earth and such other heavenly bodies as had at that time been discovered as having a magnetic field, was exerci...

  17. Planetary Airplane Extraction System Development and Subscale Testing

    Science.gov (United States)

    Teter, John E., Jr.

    2006-01-01

    The Aerial Regional-scale Environmental Survey (ARES) project will employ an airplane as the science platform from which to collect science data in the previously inaccessible, thin atmosphere of Mars. In order for the airplane to arrive safely in the Martian atmosphere, a number of sequences must occur. A critical element in the entry sequence at Mars is an extraction maneuver to separate the airplane quickly (in less than a second) from its protective backshell to reduce the possibility of re-contact, potentially leading to mission failure. This paper describes the development, testing, and lessons learned from building a 1/3 scale model of this airplane extraction system. This design, based on the successful Mars Exploration Rover (MER) extraction mechanism, employs a series of trucks rolling along tracks located on the surface of the central parachute can. Numerous tests using high speed video were conducted at the Langley Research Center to validate this concept. One area of concern was that that although the airplane released cleanly, a pitching moment could be introduced. While targeted for a Mars mission, this concept will enable environmental surveys by aircraft in other planetary bodies with a sensible atmosphere such as Venus or Saturn's moon, Titan.

  18. VLA Reveals a Close Pair of Potential Planetary Systems

    Science.gov (United States)

    1998-09-01

    in Cambridge, MA. "However, we don't think these solar systems would be able to form outer, icy planets like Uranus and Neptune, because of the small size of the dust disks." The new observations "imply that young protoplanetary disks can contain considerably more mass within (a distance equal to Saturn's orbital radius) than astronomers have been willing to contemplate," wrote Alan P. Boss of the Carnegie Institution of Washington in an accompanying Nature article analyzing the results. If the stars were a few times closer together, the researchers point out, the gravitational effects of both would disrupt the disks and prevent any planets from forming. "If these disks form planetary systems, they would be among the closest possible adjacent sets of planets in the universe," said Rodriguez. Boss suggested that a giant planet formed near the edge of one of the disks might be ejected from the system by the gravitational effect of the companion star. This, he says, might explain the possible "runaway planet" shown in a Hubble Space Telescope image released in May. In that result, a planet appears to have been ejected by a binary-star system similar in size to that seen by the VLA. Further observations are required to confirm that result. In addition to Rodriguez and Wilner, the researchers are Paola D'Alessio, Salvador Curiel, Yolanda Gomez, Susana Lizano, Jorge Canto, and Alejandro C. Raga of the National Autonomous University in Mexico City; Paul Ho of the Harvard-Smithsonian Center for Astrophysics; Jose M. Torrelles of the Astrophysical Institute of Andalucia in Spain; and Alan Pedlar of the Jodrell Bank observatory in Britain. The observations of the double-star system were made at a radio wavelength of 7 millimeters, a wavelength at which emission from cosmic dust is readily detected. Astronomers long realized that the VLA had sufficient resolving power - the ability to see fine detail - to make images of the dust disks around young stars that form the building

  19. Organic materials in planetary and protoplanetary systems: nature or nurture?

    Science.gov (United States)

    Dalle Ore, C. M.; Fulchignoni, M.; Cruikshank, D. P.; Barucci, M. A.; Brunetto, R.; Campins, H.; de Bergh, C.; Debes, J. H.; Dotto, E.; Emery, J. P.; Grundy, W. M.; Jones, A. P.; Mennella, V.; Orthous-Daunay, F. R.; Owen, T.; Pascucci, I.; Pendleton, Y. J.; Pinilla-Alonso, N.; Quirico, E.; Strazzulla, G.

    2011-09-01

    Aims: The objective of this work is to summarize the discussion of a workshop aimed at investigating the properties, origins, and evolution of the materials that are responsible for the red coloration of the small objects in the outer parts of the solar system. Because of limitations or inconsistencies in the observations and, until recently, the limited availability of laboratory data, there are still many questions on the subject. Our goal is to approach two of the main questions in a systematic way: - Is coloring an original signature of materials that are presolar in origin ("nature") or stems from post-formational chemical alteration, or weathering ("nurture")? - What is the chemical signature of the material that causes spectra to be sloped towards the red in the visible? We examine evidence available both from the laboratory and from observations sampling different parts of the solar system and circumstellar regions (disks). Methods: We present a compilation of brief summaries gathered during the workshop and describe the evidence towards a primordial vs. evolutionary origin for the material that reddens the small objects in the outer parts of our, as well as in other, planetary systems. We proceed by first summarizing laboratory results followed by observational data collected at various distances from the Sun. Results: While laboratory experiments show clear evidence of irradiation effects, particularly from ion bombardment, the first obstacle often resides in the ability to unequivocally identify the organic material in the observations. The lack of extended spectral data of good quality and resolution is at the base of this problem. Furthermore, that both mechanisms, weathering and presolar, act on the icy materials in a spectroscopically indistinguishable way makes our goal of defining the impact of each mechanism challenging. Conclusions: Through a review of some of the workshop presentations and discussions, encompassing laboratory experiments as well

  20. Near-infrared Variability in the 2MASS Calibration Fields: A Search for Planetary Transit Candidates

    Science.gov (United States)

    Plavchan, Peter; Jura, M.; Kirkpatrick, J. Davy; Cutri, Roc M.; Gallagher, S. C.

    2008-01-01

    The Two Micron All Sky Survey (2MASS) photometric calibration observations cover approximately 6 square degrees on the sky in 35 'calibration fields,' each sampled in nominal photometric conditions between 562 and 3692 times during the 4 years of the 2MASS mission. We compile a catalog of variables from the calibration observations to search for M dwarfs transited by extrasolar planets. We present our methods for measuring periodic and nonperiodic flux variability. From 7554 sources with apparent K(sub s) magnitudes between 5.6 and 16.1, we identify 247 variables, including extragalactic variables and 23 periodic variables. We have discovered three M dwarf eclipsing systems, including two candidates for transiting extrasolar planets.

  1. Heliopause Electrostatic Rapid Transit System (HERTS)

    Science.gov (United States)

    Wiegmann, Bruce M.

    2015-01-01

    A recent six month investigation focused on: "Determining the benefits of propelling a scientific spacecraft by an 'Electric Sail' propulsion system to the edge of our solar system (the Heliopause), a distance of 100 to 120 AU, in ten years or less" has recently been completed by the Advance Concepts Office at NASA's MSFC. The concept investigated has been named the Heliopause Electrostatic Rapid Transit System (HERTS) by the MSFC team. The HERTS is a revolutionary propellant-less propulsion concept that is ideal for deep space missions to the Outer Planets, Heliopause, and beyond. It is unique in that it uses momentum exchange from naturally occurring solar wind protons to propel a spacecraft within the heliosphere. The propulsion system consists of an array of electrically positively-biased wires that extend outward 20 km from a rotating (one revolution per hour) spacecraft. It was determined that the HERTS system can accelerate a spacecraft to velocities as much as two to three times that possible by any realistic extrapolation of current state-of-the-art propulsion technologies- including solar electric and solar sail propulsion systems. The data produced show that a scientific spacecraft could reach distances of 100AU in less than 10 years. Moreover, it can be reasonably expected that this system could be developed within a decade and provide meaningful Heliophysics Science and Outer Planetary Science returns in the 2025-2035 timeframe.

  2. THE INNER DEBRIS STRUCTURE IN THE FOMALHAUT PLANETARY SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Su, Kate Y. L.; Rieke, George H.; Defrére, Denis [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Wang, Kuo-Song; Lee, Chin-Fei [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Lai, Shih-Ping [Institute of Astronomy, National Tsing Hua University (NTHU), Hsinchu 30013, Taiwan (China); Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lieshout, Rik van, E-mail: ksu@as.arizona.edu [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)

    2016-02-10

    Fomalhaut plays an important role in the study of debris disks and small bodies in other planetary systems. The proximity and luminosity of the star make key features of its debris, like the water ice line, accessible. Here we present ALMA cycle 1, 870 μm (345 GHz) observations targeted at the inner part of the Fomalhaut system with a synthesized beam of 0.″45 × 0.″37 (∼3 AU linear resolution at the distance of Fomalhaut) and an rms of 26 μJy beam{sup −1}. The high angular resolution and sensitivity of the ALMA data enable us to place strong constraints on the nature of the warm excess revealed by Spitzer and Herschel observations. We detect a point source at the star position with a total flux consistent with thermal emission from the stellar photosphere. No structures that are brighter than 3σ are detected in the central 15 AU × 15 AU region. Modeling the spectral energy distribution using parameters expected for a dust-producing planetesimal belt indicates a radial location in the range of ∼8–15 AU. This is consistent with the location where ice sublimates in Fomalhaut, i.e., an asteroid-belt analog. The 3σ upper limit for such a belt is <1.3 mJy at 870 μm. We also interpret the 2 and 8–13 μm interferometric measurements to reveal the structure in the inner 10 AU region as dust naturally connected to this proposed asteroid belt by Poynting–Robertson drag, dust sublimation, and magnetically trapped nanograins.

  3. Transition-Systems, Event Structures, and Unfoldings

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Rozenberg, Grzegorz; Thiagarajan, P.S.

    1995-01-01

    systems. Here we show that by smoothly strengthening the regional axioms for elementary transition systems, one obtains a subclass called occurrence transition system. We then prove that occurrence transition systems are the transition system model of yet another basic model of concurrency, namely, prime......A subclass of transition systems called elementary transition systems can be identified with the help of axioms based on a structural notion called regions. Elementary transition systems have been shown to be the transition system model of a basic system model of net theory called elementary net...

  4. XML-based information system for planetary sciences

    Science.gov (United States)

    Carraro, F.; Fonte, S.; Turrini, D.

    2009-04-01

    EuroPlaNet (EPN in the following) has been developed by the planetological community under the "Sixth Framework Programme" (FP6 in the following), the European programme devoted to the improvement of the European research efforts through the creation of an internal market for science and technology. The goal of the EPN programme is the creation of a European network aimed to the diffusion of data produced by space missions dedicated to the study of the Solar System. A special place within the EPN programme is that of I.D.I.S. (Integrated and Distributed Information Service). The main goal of IDIS is to offer to the planetary science community a user-friendly access to the data and information produced by the various types of research activities, i.e. Earth-based observations, space observations, modeling, theory and laboratory experiments. During the FP6 programme IDIS development consisted in the creation of a series of thematic nodes, each of them specialized in a specific scientific domain, and a technical coordination node. The four thematic nodes are the Atmosphere node, the Plasma node, the Interiors & Surfaces node and the Small Bodies & Dust node. The main task of the nodes have been the building up of selected scientific cases related with the scientific domain of each node. The second work done by EPN nodes have been the creation of a catalogue of resources related to their main scientific theme. Both these efforts have been used as the basis for the development of the main IDIS goal, i.e. the integrated distributed service. An XML-based data model have been developed to describe resources using meta-data and to store the meta-data within an XML-based database called eXist. A search engine has been then developed in order to allow users to search resources within the database. Users can select the resource type and can insert one or more values or can choose a value among those present in a list, depending on selected resource. The system searches for all

  5. The Planetary Data System (PDS) Data Dictionary Tool (LDDTool)

    Science.gov (United States)

    Raugh, Anne C.; Hughes, John S.

    2017-10-01

    One of the major design goals of the PDS4 development effort was to provide an avenue for discipline specialists and large data preparers such as mission archivists to extend the core PDS4 Information Model (IM) to include metadata definitions specific to their own contexts. This capability is critical for the Planetary Data System - an archive that deals with a data collection that is diverse along virtually every conceivable axis. Amid such diversity, it is in the best interests of the PDS archive and its users that all extensions to the core IM follow the same design techniques, conventions, and restrictions as the core implementation itself. Notwithstanding, expecting all mission and discipline archivist seeking to define metadata for a new context to acquire expertise in information modeling, model-driven design, ontology, schema formulation, and PDS4 design conventions and philosophy is unrealistic, to say the least.To bridge that expertise gap, the PDS Engineering Node has developed the data dictionary creation tool known as “LDDTool”. This tool incorporates the same software used to maintain and extend the core IM, packaged with an interface that enables a developer to create his contextual information model using the same, open standards-based metadata framework PDS itself uses. Through this interface, the novice dictionary developer has immediate access to the common set of data types and unit classes for defining attributes, and a straight-forward method for constructing classes. The more experienced developer, using the same tool, has access to more sophisticated modeling methods like abstraction and extension, and can define very sophisticated validation rules.We present the key features of the PDS Local Data Dictionary Tool, which both supports the development of extensions to the PDS4 IM, and ensures their compatibility with the IM.

  6. Capture of free-floating planets by planetary systems

    Science.gov (United States)

    Goulinski, Nadav; Ribak, Erez N.

    2018-01-01

    Evidence of exoplanets with orbits that are misaligned with the spin of the host star may suggest that not all bound planets were born in the protoplanetary disc of their current planetary system. Observations have shown that free-floating Jupiter-mass objects can exceed the number of stars in our Galaxy, implying that capture scenarios may not be so rare. To address this issue, we construct a three-dimensional simulation of a three-body scattering between a free-floating planet and a star accompanied by a Jupiter-mass bound planet. We distinguish between three different possible scattering outcomes, where the free-floating planet may get weakly captured after the brief interaction with the binary, remain unbound or 'kick out' the bound planet and replace it. The simulation was performed for different masses of the free-floating planets and stars, as well as different impact parameters, inclination angles and approach velocities. The outcome statistics are used to construct an analytical approximation of the cross-section for capturing a free-floating planet by fitting their dependence on the tested variables. The analytically approximated cross-section is used to predict the capture rate for these kinds of objects, and to estimate that about 1 per cent of all stars are expected to experience a temporary capture of a free-floating planet during their lifetime. Finally, we propose additional physical processes that may increase the capture statistics and whose contribution should be considered in future simulations in order to determine the fate of the temporarily captured planets.

  7. A planetary nervous system for social mining and collective awareness

    Science.gov (United States)

    Giannotti, F.; Pedreschi, D.; Pentland, A.; Lukowicz, P.; Kossmann, D.; Crowley, J.; Helbing, D.

    2012-11-01

    We present a research roadmap of a Planetary Nervous System (PNS), capable of sensing and mining the digital breadcrumbs of human activities and unveiling the knowledge hidden in the big data for addressing the big questions about social complexity. We envision the PNS as a globally distributed, self-organizing, techno-social system for answering analytical questions about the status of world-wide society, based on three pillars: social sensing, social mining and the idea of trust networks and privacy-aware social mining. We discuss the ingredients of a science and a technology necessary to build the PNS upon the three mentioned pillars, beyond the limitations of their respective state-of-art. Social sensing is aimed at developing better methods for harvesting the big data from the techno-social ecosystem and make them available for mining, learning and analysis at a properly high abstraction level. Social mining is the problem of discovering patterns and models of human behaviour from the sensed data across the various social dimensions by data mining, machine learning and social network analysis. Trusted networks and privacy-aware social mining is aimed at creating a new deal around the questions of privacy and data ownership empowering individual persons with full awareness and control on own personal data, so that users may allow access and use of their data for their own good and the common good. The PNS will provide a goal-oriented knowledge discovery framework, made of technology and people, able to configure itself to the aim of answering questions about the pulse of global society. Given an analytical request, the PNS activates a process composed by a variety of interconnected tasks exploiting the social sensing and mining methods within the transparent ecosystem provided by the trusted network. The PNS we foresee is the key tool for individual and collective awareness for the knowledge society. We need such a tool for everyone to become fully aware of how

  8. TRANSIT TIMING VARIATIONS FOR INCLINED AND RETROGRADE EXOPLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Payne, Matthew J.; Ford, Eric B.; Veras, Dimitri

    2010-01-01

    We perform numerical calculations of the expected transit timing variations (TTVs) induced on a hot-Jupiter by an Earth-mass perturber. Motivated by the recent discoveries of retrograde transiting planets, we concentrate on an investigation of the effect of varying relative planetary inclinations, up to and including completely retrograde systems. We find that planets in low-order (e.g., 2:1) mean-motion resonances (MMRs) retain approximately constant TTV amplitudes for 0 deg. 170 deg. Systems in higher order MMRs (e.g., 5:1) increase in TTV amplitude as inclinations increase toward 45 deg., becoming approximately constant for 45 deg. 135 deg. Planets away from resonance slowly decrease in TTV amplitude as inclinations increase from 0 deg. to 180 deg., whereas planets adjacent to resonances can exhibit a huge range of variability in TTV amplitude as a function of both eccentricity and inclination. For highly retrograde systems (135 deg. < i ≤ 180 deg.), TTV signals will be undetectable across almost the entirety of parameter space, with the exceptions occurring when the perturber has high eccentricity or is very close to an MMR. This high inclination decrease in TTV amplitude (on and away from resonance) is important for the analysis of the known retrograde and multi-planet transiting systems, as inclination effects need to be considered if TTVs are to be used to exclude the presence of any putative planetary companions: absence of evidence is not evidence of absence.

  9. Phase transitions in finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire

    2002-07-01

    In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

  10. Phase transitions in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Gulminelli, F.

    2002-01-01

    In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

  11. A Path to Planetary Protection Requirements for Human Exploration: A Literature Review and Systems Engineering Approach

    Science.gov (United States)

    Johnson, James E.; Conley, Cassie; Siegel, Bette

    2015-01-01

    As systems, technologies, and plans for the human exploration of Mars and other destinations beyond low Earth orbit begin to coalesce, it is imperative that frequent and early consideration is given to how planetary protection practices and policy will be upheld. While the development of formal planetary protection requirements for future human space systems and operations may still be a few years from fruition, guidance to appropriately influence mission and system design will be needed soon to avoid costly design and operational changes. The path to constructing such requirements is a journey that espouses key systems engineering practices of understanding shared goals, objectives and concerns, identifying key stakeholders, and iterating a draft requirement set to gain community consensus. This paper traces through each of these practices, beginning with a literature review of nearly three decades of publications addressing planetary protection concerns with respect to human exploration. Key goals, objectives and concerns, particularly with respect to notional requirements, required studies and research, and technology development needs have been compiled and categorized to provide a current 'state of knowledge'. This information, combined with the identification of key stakeholders in upholding planetary protection concerns for human missions, has yielded a draft requirement set that might feed future iteration among space system designers, exploration scientists, and the mission operations community. Combining the information collected with a proposed forward path will hopefully yield a mutually agreeable set of timely, verifiable, and practical requirements for human space exploration that will uphold international commitment to planetary protection.

  12. Unstable low-mass planetary systems as drivers of white dwarf pollution

    Science.gov (United States)

    Mustill, Alexander J.; Villaver, Eva; Veras, Dimitri; Gänsicke, Boris T.; Bonsor, Amy

    2018-05-01

    At least 25 {per cent} of white dwarfs show atmospheric pollution by metals, sometimes accompanied by detectable circumstellar dust/gas discs or (in the case of WD 1145+017) transiting disintegrating asteroids. Delivery of planetesimals to the white dwarf by orbiting planets is a leading candidate to explain these phenomena. Here, we study systems of planets and planetesimals undergoing planet-planet scattering triggered by the star's post-main-sequence mass loss, and test whether this can maintain high rates of delivery over the several Gyr that they are observed. We find that low-mass planets (Earth to Neptune mass) are efficient deliverers of material and can maintain the delivery for Gyr. Unstable low-mass planetary systems reproduce the observed delayed onset of significant accretion, as well as the slow decay in accretion rates at late times. Higher-mass planets are less efficient, and the delivery only lasts a relatively brief time before the planetesimal populations are cleared. The orbital inclinations of bodies as they cross the white dwarf's Roche limit are roughly isotropic, implying that significant collisional interactions of asteroids, debris streams and discs can be expected. If planet-planet scattering is indeed responsible for the pollution of white dwarfs, many such objects, and their main-sequence progenitors, can be expected to host (currently undetectable) super-Earth planets on orbits of several au and beyond.

  13. THE HOMOGENEOUS STUDY OF TRANSITING SYSTEMS (HoSTS). I. THE PILOT STUDY OF WASP-13

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Maqueo Chew, Yilen; Cargile, Phillip; Hebb, Leslie; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Faedi, Francesca; Pollacco, Don [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Doyle, Amanda P.; Smalley, Barry [Astrophysics Group, Keele University, Staffordshire ST5 5BG (United Kingdom); Ghezzi, Luan; Cunha, Katia; Smith, Verne V. [Observatorio Nacional, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ 20921-400 (Brazil); Sousa, Sergio; Santos, Nuno C. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Barros, Susana C. C. [LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, Aix Marseille Universite, CNRS, F-13388 Marseille (France); Schuler, Simon C. [Stewart Observatory, University of Arizona, Tucson, AZ 85721 (United States); Collier Cameron, Andrew, E-mail: yilen.gomez@vanderbilt.edu [School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom)

    2013-05-01

    We present the fundamental stellar and planetary properties of the transiting planetary system WASP-13 within the framework of the Homogeneous Study of Transiting Systems (HoSTS). HoSTS aims to derive the fundamental stellar (T{sub eff}, [Fe/H], M{sub *}, R{sub *}) and planetary (M{sub pl}, R{sub pl}, T{sub eq}) physical properties of known transiting planets using a consistent methodology and homogeneous high-quality data set. Four spectral analysis techniques are independently applied to a Keck+HIRES spectrum of WASP-13 considering two distinct cases: unconstrained parameters and constrained log g from transit light curves. We check the derived stellar temperature against that from a different temperature diagnostic based on an INT+IDS H{alpha} spectrum. The four unconstrained analyses render results that are in good agreement, and provide an improvement of 50% in the precision of T{sub eff}, and of 85% in [Fe/H] with respect to the WASP-13 discovery paper. The planetary parameters are then derived via the Monte Carlo Markov Chain modeling of the radial velocity and light curves, in iteration with stellar evolutionary models to derive realistic uncertainties. WASP-13 (1.187 {+-} 0.065 M{sub Sun }; 1.574 {+-} 0.048 R{sub Sun }) hosts a Saturn-mass, transiting planet (0.500 {+-} 0.037 M{sub Jup}; 1.407 {+-} 0.052 R{sub Jup}), and is at the end of its main-sequence lifetime (4-5.5 Gyr). Our analysis of WASP-13 showcases that both a detailed stellar characterization and transit modeling are necessary to well determine the fundamental properties of planetary systems, which are paramount in identifying and determining empirical relationships between transiting planets and their hosts.

  14. Geometric transitions and integrable systems

    International Nuclear Information System (INIS)

    Diaconescu, D.-E.; Dijkgraaf, R.; Donagi, R.; Hofman, C.; Pantev, T.

    2006-01-01

    We consider B-model large N duality for a new class of noncompact Calabi-Yau spaces modeled on the neighborhood of a ruled surface in a Calabi-Yau threefold. The closed string side of the transition is governed at genus zero by an A 1 Hitchin integrable system on a genus g Riemann surface Σ. The open string side is described by a holomorphic Chern-Simons theory which reduces to a generalized matrix model in which the eigenvalues lie on the compact Riemann surface Σ. We show that the large N planar limit of the generalized matrix model is governed by the same A 1 Hitchin system therefore proving genus zero large N duality for this class of transitions

  15. Design of Mobility System for Ground Model of Planetary Exploration Rover

    Directory of Open Access Journals (Sweden)

    Younkyu Kim

    2012-12-01

    Full Text Available In recent years, a number of missions have been planned and conducted worldwide on the planets such as Mars, which involves the unmanned robotic exploration with the use of rover. The rover is an important system for unmanned planetary exploration, performing the locomotion and sample collection and analysis at the exploration target of the planetary surface designated by the operator. This study investigates the development of mobility system for the rover ground model necessary to the planetary surface exploration for the benefit of future planetary exploration mission in Korea. First, the requirements for the rover mobility system are summarized and a new mechanism is proposed for a stable performance on rough terrain which consists of the passive suspension system with 8 wheeled double 4-bar linkage (DFBL, followed by the performance evaluation for the mechanism of the mobility system based on the shape design and simulation. The proposed mobility system DFBL was compared with the Rocker-Bogie suspension system of US space agency National Aeronautics and Space Administration and 8 wheeled mobility system CRAB8 developed in Switzerland, using the simulation to demonstrate the superiority with respect to the stability of locomotion. On the basis of the simulation results, a general system configuration was proposed and designed for the rover manufacture.

  16. PyTranSpot: A tool for multiband light curve modeling of planetary transits and stellar spots

    Science.gov (United States)

    Juvan, Ines G.; Lendl, M.; Cubillos, P. E.; Fossati, L.; Tregloan-Reed, J.; Lammer, H.; Guenther, E. W.; Hanslmeier, A.

    2018-02-01

    Several studies have shown that stellar activity features, such as occulted and non-occulted starspots, can affect the measurement of transit parameters biasing studies of transit timing variations and transmission spectra. We present PyTranSpot, which we designed to model multiband transit light curves showing starspot anomalies, inferring both transit and spot parameters. The code follows a pixellation approach to model the star with its corresponding limb darkening, spots, and transiting planet on a two dimensional Cartesian coordinate grid. We combine PyTranSpot with a Markov chain Monte Carlo framework to study and derive exoplanet transmission spectra, which provides statistically robust values for the physical properties and uncertainties of a transiting star-planet system. We validate PyTranSpot's performance by analyzing eleven synthetic light curves of four different star-planet systems and 20 transit light curves of the well-studied WASP-41b system. We also investigate the impact of starspots on transit parameters and derive wavelength dependent transit depth values for WASP-41b covering a range of 6200-9200 Å, indicating a flat transmission spectrum.

  17. How do giant planetary cores shape the dust disk? HL Tau system

    OpenAIRE

    Picogna, Giovanni; Kley, Wilhelm

    2015-01-01

    We are observing, thanks to ALMA, the dust distribution in the region of active planet formation around young stars. This is a powerful tool to connect observations with theoretical models and improve our understandings of the processes at play. We want to test how a multi-planetary system shapes its birth disk and study the influence of the planetary masses and particle sizes on the final dust distribution. Moreover, we apply our model to the HL Tau system in order to obtain some insights on...

  18. Conceptual design of planetary gearbox system for constant generator speed in hydro power plant

    Directory of Open Access Journals (Sweden)

    Bhargav

    2018-01-01

    Full Text Available Micro Hydro Power Plant (MHPP is emerging as one of the most clean, renewable and reliable energy technology for harnessing power. In MHPP hydro governors are avoided, that results in turbine speed fluctuation. MHPP requires either speed or torque amplification of generator for constant power generation. To achieve this, planetary gear transmission system is explored for MHPP due to its higher efficiency and compact size. A conceptual planetary gearbox system is developed for MHPP to maintain constant generator speed. The conceptual gearbox is designed, modelled and analysed using ADAMS software. Simulation results are found to be in close agreement with analytical results. Hence, conceptual design of planetary gearbox can be used to govern constant generator speed. In this paper, a MHPP which generate constant power of 5 kW at constant generator speed of 1490 rpm is analysed and validated

  19. Comparative Climates of the Trappist-1 Planetary System: Results from a Simple Climate-vegetation Model

    International Nuclear Information System (INIS)

    Alberti, Tommaso; Carbone, Vincenzo; Lepreti, Fabio; Vecchio, Antonio

    2017-01-01

    The recent discovery of the planetary system hosted by the ultracool dwarf star TRAPPIST-1 could open new paths for investigations of the planetary climates of Earth-sized exoplanets, their atmospheres, and their possible habitability. In this paper, we use a simple climate-vegetation energy-balance model to study the climate of the seven TRAPPIST-1 planets and the climate dependence on various factors: the global albedo, the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions. The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a “surface water zone (SWZ)”) in different planetary conditions, with or without the presence of a greenhouse effect. It is shown that planet TRAPPIST-1d seems to be the most stable from an Earth-like perspective, since it resides in the SWZ for a wide range of reasonable values of the model parameters. Moreover, according to the model, outer planets (f, g, and h) cannot host liquid water on their surfaces, even with Earth-like conditions, entering a snowball state. Although very simple, the model allows us to extract the main features of the TRAPPIST-1 planetary climates.

  20. Comparative Climates of the Trappist-1 Planetary System: Results from a Simple Climate-vegetation Model

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, Tommaso; Carbone, Vincenzo; Lepreti, Fabio [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, I-87036, Rende (CS) (Italy); Vecchio, Antonio, E-mail: tommaso.alberti@unical.it, E-mail: tommasoalberti89@gmail.com [LESIA—Observatoire de Paris, PSL Research University, 5 place Jules Janssen, F-92190, Meudon (France)

    2017-07-20

    The recent discovery of the planetary system hosted by the ultracool dwarf star TRAPPIST-1 could open new paths for investigations of the planetary climates of Earth-sized exoplanets, their atmospheres, and their possible habitability. In this paper, we use a simple climate-vegetation energy-balance model to study the climate of the seven TRAPPIST-1 planets and the climate dependence on various factors: the global albedo, the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions. The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a “surface water zone (SWZ)”) in different planetary conditions, with or without the presence of a greenhouse effect. It is shown that planet TRAPPIST-1d seems to be the most stable from an Earth-like perspective, since it resides in the SWZ for a wide range of reasonable values of the model parameters. Moreover, according to the model, outer planets (f, g, and h) cannot host liquid water on their surfaces, even with Earth-like conditions, entering a snowball state. Although very simple, the model allows us to extract the main features of the TRAPPIST-1 planetary climates.

  1. Physical properties of the WASP-67 planetary system from multi-colour photometry

    Science.gov (United States)

    Mancini, L.; Southworth, J.; Ciceri, S.; Calchi Novati, S.; Dominik, M.; Henning, Th.; Jørgensen, U. G.; Korhonen, H.; Nikolov, N.; Alsubai, K. A.; Bozza, V.; Bramich, D. M.; D'Ago, G.; Figuera Jaimes, R.; Galianni, P.; Gu, S.-H.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Kains, N.; Popovas, A.; Rabus, M.; Rahvar, S.; Skottfelt, J.; Snodgrass, C.; Street, R.; Surdej, J.; Tsapras, Y.; Vilela, C.; Wang, X.-B.; Wertz, O.

    2014-08-01

    Context. The extrasolar planet WASP-67 b is the first hot Jupiter definitively known to undergo only partial eclipses. The lack of the second and third contact points in this planetary system makes it difficult to obtain accurate measurements of its physical parameters. Aims: By using new high-precision photometric data, we confirm that WASP-67 b shows grazing eclipses and compute accurate estimates of the physical properties of the planet and its parent star. Methods: We present high-quality, multi-colour, broad-band photometric observations comprising five light curves covering two transit events, obtained using two medium-class telescopes and the telescope-defocusing technique. One transit was observed through a Bessel-R filter and the other simultaneously through filters similar to Sloan g'r'i'z'. We modelled these data using jktebop. The physical parameters of the system were obtained from the analysis of these light curves and from published spectroscopic measurements. Results: All five of our light curves satisfy the criterion for being grazing eclipses. We revise the physical parameters of the whole WASP-67 system and, in particular, significantly improve the measurements of the planet's radius (Rb = 1.091 ± 0.046 RJup) and density (ρb = 0.292 ± 0.036 ρJup), as compared to the values in the discovery paper (Rb = 1.4 -0.2+0.3 RJup and ρb = 0.16 ± 0.08 ρJup). The transit ephemeris was also substantially refined. We investigated the variation of the planet's radius as a function of the wavelength, using the simultaneous multi-band data, finding that our measurements are consistent with a flat spectrum to within the experimental uncertainties. Based on data collected with GROND at the MPG 2.2 m telescope and DFOSC at the Danish 1.54 m telescope.Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/A127

  2. Using the Hobby-Eberly telescope to place constraints on planetary system formation

    International Nuclear Information System (INIS)

    Cochran, William D; Endl, Michael

    2008-01-01

    We are conducting several radial velocity surveys with the 9.2 m Hobby-Eberly telescope (HET). These surveys are designed to improve our understanding of the physics of planetary system formation and evolution. We present recent results from two of these HET surveys. The first is from our survey of metal-poor stars. This survey is designed to probe the physics of planet formation at low metallicities. We present the detection of two planetary companions to HD 155358, a star with [Fe/H] of -0.68. This is the lowest metallicity of any planet host star

  3. Hawaiian hydrogen mass transit system

    International Nuclear Information System (INIS)

    Russell, G.W.; Russell, A.

    1990-01-01

    This paper proposes a joint effort between the scientific and business communities; to create, make and have hydrogen fuel become the primary fuel of the future. Hawaii has abundant, unharnessed renewable resources yet imports almost all of its fuel. Initiating hydrogen production and industrial application in conjunction with a prototype pilot project such as this mass transit system would not only accomplish the joining of science and business but give an environmentally safe energy alternative to the state and people of Hawaii and hopefully the world

  4. Richest Planetary System Discovered - Up to seven planets orbiting a Sun-like star

    Science.gov (United States)

    2010-08-01

    content of its host star. All very massive planetary systems are found around massive and metal-rich stars, while the four lowest-mass systems are found around lower-mass and metal-poor stars [5]. Such properties confirm current theoretical models. The discovery is announced today at the international colloquium "Detection and dynamics of transiting exoplanets", at the Observatoire de Haute-Provence, France. Notes [1] Using the radial velocity method, astronomers can only estimate a minimum mass for a planet as the mass estimate also depends on the tilt of the orbital plane relative to the line of sight, which is unknown. From a statistical point of view, this minimum mass is however often close to the real mass of the planet. [2] (added 30 August 2010) HD 10180b would be the lowest mass exoplanet discovered orbiting a "normal" star like our Sun. However, lower mass exoplanets have been previously discovered orbiting the pulsar PSR B1257+12 (a highly magnetised rotating neutron star). [3] On average the planets in the inner region of the HD 10180 system have 20 times the mass of the Earth, whereas the inner planets in our own Solar System (Mercury, Venus, Earth and Mars) have an average mass of half that of the Earth. [4] The Titius-Bode law states that the distances of the planets from the Sun follow a simple pattern. For the outer planets, each planet is predicted to be roughly twice as far away from the Sun as the previous object. The hypothesis correctly predicted the orbits of Ceres and Uranus, but failed as a predictor of Neptune's orbit. [5] According to the definition used in astronomy, "metals" are all the elements other than hydrogen and helium. Such metals, except for a very few minor light chemical elements, have all been created by the various generations of stars. Rocky planets are made of "metals". More information This research was presented in a paper submitted to Astronomy and Astrophysics ("The HARPS search for southern extra-solar planets. XXVII. Up to

  5. Physical properties of the planetary systems WASP-45 and WASP-46 from simultaneous multiband photometry

    DEFF Research Database (Denmark)

    Ciceri, S.; Mancini, L.; Southworth, J.

    2016-01-01

    Accurate measurements of the physical characteristics of a large number of exoplanets are useful to strongly constrain theoretical models of planet formation and evolution, which lead to the large variety of exoplanets and planetary-system configurations that have been observed. We present a stud...

  6. Characterization of the planetary system Kepler-101 with HARPS-N

    DEFF Research Database (Denmark)

    Bonomo, A. S.; Sozzetti, A.; Lovis, C.

    2014-01-01

    faintness of the parent star for highly precise radial-velocity measurements (Kp = 13.8) and the limited number of radial velocities. The 1σ upper limit, Mp3.8 M⊕, excludes a pure iron composition with a probability of 68.3%. The architecture of the planetary system Kepler-101 − containing a close...

  7. PLANETARY SYSTEM FORMATION IN THE PROTOPLANETARY DISK AROUND HL TAURI

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Eiji; Hasegawa, Yasuhiro; Hayashi, Masahiko; Iguchi, Satoru, E-mail: eiji.akiyama@nao.ac.jp, E-mail: yasuhiro.hasegawa@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-02-20

    We reprocess the Atacama Large Millimeter/Submillimeter Array (ALMA) long-baseline science verification data taken toward HL Tauri. Assuming the observed gaps are opened up by currently forming, unseen bodies, we estimate the mass of such hypothetical bodies based on the following two approaches: the Hill radius analysis and a more elaborate approach developed from the angular momentum transfer analysis in gas disks. For the former, the measured gap widths are used for estimating the mass of the bodies, while for the latter, the measured gap depths are utilized. We show that their masses are comparable to or less than the mass of Jovian planets. By evaluating Toomre’s gravitational instability (GI) condition and cooling effect, we find that the GI might be a mechanism to form the bodies in the outer region of the disk. As the disk might be gravitationally unstable only in the outer region of the disk, inward planetary migration would be needed to construct the current architecture of the observed disk. We estimate the gap-opening mass and show that type II migration might be able to play such a role. Combining GIs with inward migration, we conjecture that all of the observed gaps may be a consequence of bodies that might have originally formed at the outer part of the disk, and have subsequently migrated to the current locations. While ALMA’s unprecedented high spatial resolution observations can revolutionize our picture of planet formation, more dedicated observational and theoretical studies are needed to fully understand the HL Tauri images.

  8. PLANETARY SYSTEM FORMATION IN THE PROTOPLANETARY DISK AROUND HL TAURI

    International Nuclear Information System (INIS)

    Akiyama, Eiji; Hasegawa, Yasuhiro; Hayashi, Masahiko; Iguchi, Satoru

    2016-01-01

    We reprocess the Atacama Large Millimeter/Submillimeter Array (ALMA) long-baseline science verification data taken toward HL Tauri. Assuming the observed gaps are opened up by currently forming, unseen bodies, we estimate the mass of such hypothetical bodies based on the following two approaches: the Hill radius analysis and a more elaborate approach developed from the angular momentum transfer analysis in gas disks. For the former, the measured gap widths are used for estimating the mass of the bodies, while for the latter, the measured gap depths are utilized. We show that their masses are comparable to or less than the mass of Jovian planets. By evaluating Toomre’s gravitational instability (GI) condition and cooling effect, we find that the GI might be a mechanism to form the bodies in the outer region of the disk. As the disk might be gravitationally unstable only in the outer region of the disk, inward planetary migration would be needed to construct the current architecture of the observed disk. We estimate the gap-opening mass and show that type II migration might be able to play such a role. Combining GIs with inward migration, we conjecture that all of the observed gaps may be a consequence of bodies that might have originally formed at the outer part of the disk, and have subsequently migrated to the current locations. While ALMA’s unprecedented high spatial resolution observations can revolutionize our picture of planet formation, more dedicated observational and theoretical studies are needed to fully understand the HL Tauri images

  9. TRANSITIONAL DISKS AS SIGNPOSTS OF YOUNG, MULTIPLANET SYSTEMS

    International Nuclear Information System (INIS)

    Dodson-Robinson, Sarah E.; Salyk, Colette

    2011-01-01

    Although there has yet been no undisputed discovery of a still-forming planet embedded in a gaseous protoplanetary disk, the cleared inner holes of transitional disks may be signposts of young planets. Here, we show that the subset of accreting transitional disks with wide, optically thin inner holes of 15 AU or more can only be sculpted by multiple planets orbiting inside each hole. Multiplanet systems provide two key ingredients for explaining the origins of transitional disks. First, multiple planets can clear wide inner holes where single planets open only narrow gaps. Second, the confined, non-axisymmetric accretion flows produced by multiple planets provide a way for an arbitrary amount of mass transfer to occur through an apparently optically thin hole without overproducing infrared excess flux. Rather than assuming that the gas and dust in the hole are evenly and axisymmetrically distributed, one can construct an inner hole with apparently optically thin infrared fluxes by covering a macroscopic fraction of the hole's surface area with locally optically thick tidal tails. We also establish that other clearing mechanisms, such as photoevaporation, cannot explain our subset of accreting transitional disks with wide holes. Transitional disks are therefore high-value targets for observational searches for young planetary systems.

  10. Implementation of cartographic symbols for planetary mapping in geographic information systems

    Science.gov (United States)

    Nass, A.; van Gasselt, S.; Jaumann, R.; Asche, H.

    2011-09-01

    The steadily growing international interest in the exploration of planets in our Solar System and many advances in the development of space-sensor technology have led to the launch of a multitude of planetary missions to Mercury, Venus, the Earth's moon, Mars and various Outer-Solar System objects, such as the Jovian and Saturnian satellites. Camera instruments carried along on these missions image surfaces in different wavelength ranges and under different viewing angles, permitting additional data to be derived, such as spectral data or digital terrain models. Such data enable researchers to explore and investigate the development of planetary surfaces by analyzing and interpreting the inventory of surface units and structures. Results of such work are commonly abstracted and represented in thematic, mostly geological and geomorphological, maps. In order to facilitate efficient collaboration among different planetary research disciplines, mapping results need to be prepared, described, managed, archived, and visualized in a uniform way. These tasks have been increasingly carried out by means of computer-based geographic information systems (GIS or GI systems) which have come to be widely employed in the field of planetary research since the last two decades. In this paper we focus on the simplification of mapping processes, putting specific emphasis on a cartographically correct visualization of planetary mapping data using GIS-based environments. We present and discuss the implementation of a set of standardized cartographic symbols for planetary mapping based on the Digital Cartographic Standard for Geologic Map Symbolization as prepared by the United States Geological Survey (USGS) for the Federal Geographic Data Committee (FGDC). Furthermore, we discuss various options to integrate this symbol catalog into generic GI systems, and more specifically into the Environmental Systems Research Institute's (ESRI) ArcGIS environment, and focus on requirements for

  11. Planetary Magnetism

    International Nuclear Information System (INIS)

    Russell, C.T.

    1980-01-01

    Planetary spacecraft have now probed the magnetic fields of all the terrestrial planets, the moon, Jupiter, and Saturn. These measurements reveal that dynamos are active in at least four of the planets, Mercury, the earth, Jupiter, and Saturn but that Venus and Mars appear to have at most only very weak planetary magnetic fields. The moon may have once possessed an internal dynamo, for the surface rocks are magnetized. The large satellites of the outer solar system are candidates for dynamo action in addition to the large planets themselves. Of these satellites the one most likely to generate its own internal magnetic field is Io

  12. PLANETARY TRANSIT CANDIDATES IN THE CSTAR FIELD: ANALYSIS OF THE 2008 DATA

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Songhu; Zhang, Hui; Zhou, Ji-Lin; Yang, Ming; Liu, Huigen; Meng, Zeyang [School of Astronomy and Space Science and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, Nanjing 210093 (China); Zhou, Xu; Fan, Zhou; Liu, Qiang; Ma, Jun [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wang, Lifan; Feng, Long-Long [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Bayliss, D.; Zhou, G. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Ashley, M. C. B.; Lawrence, J. S.; Luong-Van, D. M.; Storey, J. W. V.; Wittenmyer, R. A. [School of Physics, University of New South Wales, NSW 2052 (Australia); Gong, Xuefei, E-mail: zhoujl@nju.edu.cn, E-mail: zhouxu@bao.ac.cn [Nanjing Institute of Astronomical Optics and Technology, Nanjing 210042 (China); and others

    2014-04-01

    The Chinese Small Telescope ARray (CSTAR) is a group of four identical, fully automated, static 14.5 cm telescopes. CSTAR is located at Dome A, Antarctica and covers 20 deg{sup 2} of sky around the South Celestial Pole. The installation is designed to provide high-cadence photometry for the purpose of monitoring the quality of the astronomical observing conditions at Dome A and detecting transiting exoplanets. CSTAR has been operational since 2008, and has taken a rich and high-precision photometric data set of 10,690 stars. In the first observing season, we obtained 291,911 qualified science frames with 20 s integrations in the i band. Photometric precision reaches ∼4 mmag at 20 s cadence at i = 7.5 and is ∼20 mmag at i = 12. Using robust detection methods, 10 promising exoplanet candidates were found. Four of these were found to be giants using spectroscopic follow-up. All of these transit candidates are presented here along with the discussion of their detailed properties as well as the follow-up observations.

  13. From circumstellar disks to planetary systems: observation and modeling of protoplanetary disks

    OpenAIRE

    Macías Quevedo, Enrique

    2016-01-01

    The existence of exoplanetary systems was first predicted after the discovery of accretion disks around young stars. Nowadays, with nearly 3500 exoplanets discovered, and almost 5000 more candidates identified by the Kepler space mission, planetary systems are now known to be ubiquitous around low-mass stars. The formation of these systems takes place during the stellar formation itself, from the dust and gas orbiting around the star in the protoplanetary disks. However, the process that lead...

  14. Secular chaos and its application to Mercury, hot Jupiters, and the organization of planetary systems.

    Science.gov (United States)

    Lithwick, Yoram; Wu, Yanqin

    2014-09-02

    In the inner solar system, the planets' orbits evolve chaotically, driven primarily by secular chaos. Mercury has a particularly chaotic orbit and is in danger of being lost within a few billion years. Just as secular chaos is reorganizing the solar system today, so it has likely helped organize it in the past. We suggest that extrasolar planetary systems are also organized to a large extent by secular chaos. A hot Jupiter could be the end state of a secularly chaotic planetary system reminiscent of the solar system. However, in the case of the hot Jupiter, the innermost planet was Jupiter (rather than Mercury) sized, and its chaotic evolution was terminated when it was tidally captured by its star. In this contribution, we review our recent work elucidating the physics of secular chaos and applying it to Mercury and to hot Jupiters. We also present results comparing the inclinations of hot Jupiters thus produced with observations.

  15. Secular chaos and its application to Mercury, hot Jupiters, and the organization of planetary systems

    Science.gov (United States)

    Lithwick, Yoram; Wu, Yanqin

    2014-01-01

    In the inner solar system, the planets’ orbits evolve chaotically, driven primarily by secular chaos. Mercury has a particularly chaotic orbit and is in danger of being lost within a few billion years. Just as secular chaos is reorganizing the solar system today, so it has likely helped organize it in the past. We suggest that extrasolar planetary systems are also organized to a large extent by secular chaos. A hot Jupiter could be the end state of a secularly chaotic planetary system reminiscent of the solar system. However, in the case of the hot Jupiter, the innermost planet was Jupiter (rather than Mercury) sized, and its chaotic evolution was terminated when it was tidally captured by its star. In this contribution, we review our recent work elucidating the physics of secular chaos and applying it to Mercury and to hot Jupiters. We also present results comparing the inclinations of hot Jupiters thus produced with observations. PMID:24367108

  16. New Discoveries in Planetary Systems and Star Formation through Advances in Laboratory Astrophysics

    OpenAIRE

    WGLA, AAS; Brickhouse, Nancy; Cowan, John; Drake, Paul; Federman, Steven; Ferland, Gary; Frank, Adam; Herbst, Eric; Olive, Keith; Salama, Farid; Savin, Daniel Wolf; Ziurys, Lucy

    2009-01-01

    As the panel on Planetary Systems and Star Formation (PSF) is fully aware, the next decade will see major advances in our understanding of these areas of research. To quote from their charge, these advances will occur in studies of solar system bodies (other than the Sun) and extrasolar planets, debris disks, exobiology, the formation of individual stars, protostellar and protoplanetary disks, molecular clouds and the cold ISM, dust, and astrochemistry. Central to the progress in these areas ...

  17. Channel coding and data compression system considerations for efficient communication of planetary imaging data

    Science.gov (United States)

    Rice, R. F.

    1974-01-01

    End-to-end system considerations involving channel coding and data compression are reported which could drastically improve the efficiency in communicating pictorial information from future planetary spacecraft. In addition to presenting new and potentially significant system considerations, this report attempts to fill a need for a comprehensive tutorial which makes much of this very subject accessible to readers whose disciplines lie outside of communication theory.

  18. SPICE: A Geometry Information System Supporting Planetary Mapping, Remote Sensing and Data Mining

    Science.gov (United States)

    Acton, C.; Bachman, N.; Semenov, B.; Wright, E.

    2013-01-01

    SPICE is an information system providing space scientists ready access to a wide assortment of space geometry useful in planning science observations and analyzing the instrument data returned therefrom. The system includes software used to compute many derived parameters such as altitude, LAT/LON and lighting angles, and software able to find when user-specified geometric conditions are obtained. While not a formal standard, it has achieved widespread use in the worldwide planetary science community

  19. CCS, locations and asynchronous transition systems

    DEFF Research Database (Denmark)

    Mukund, Madhavan; Nielsen, Mogens

    1992-01-01

    We provide a simple non-interleaved operational semantics for CCS in terms of asynchronous transition systems. We identify the concurrency present in the system in a natural way, in terms of events occurring at independent locations in the system. We extend the standard interleaving transition...... system for CCS by introducing labels on the transitions with information about the locations of events. We then show that the resulting transition system is an asynchronous transition system which has the additional property of being elementary, which means that it can also be represented by a 1-safe net....... We also introduce a notion of bisimulation on asynchronous transition systems which preserves independence. We conjecture that the induced equivalence on CCS processes coincides with the notion of location equivalence proposed by Boudol et al....

  20. The development of the human exploration demonstration project (HEDP), a planetary systems testbed

    Science.gov (United States)

    Chevers, Edward S.; Korsmeyer, David J.

    1993-01-01

    The Human Exploration Demonstration Project (HEDP) is an ongoing task at the National Aeronautics and Space Administration's Ames Research Center to address the advanced technology requirements necessary to implement an integrated working and living environment for a planetary surface habitat. The integrated environment will consist of life support systems, physiological monitoring of project crew, a virtual environment workstation, and centralized data acquisition and habitat systems health monitoring. There will be several robotic systems on a simulated planetary landscape external to the habitat environment to provide representative work loads for the crew. This paper describes the status of the HEDP after one year, the major facilities composing the HEDP, the project's role as an Ames Research Center testbed, and the types of demonstration scenarios that will be run to showcase the technologies.

  1. An Automated Sample Processing System for Planetary Exploration

    Science.gov (United States)

    Soto, Juancarlos; Lasnik, James; Roark, Shane; Beegle, Luther

    2012-01-01

    An Automated Sample Processing System (ASPS) for wet chemistry processing of organic materials on the surface of Mars has been jointly developed by Ball Aerospace and the Jet Propulsion Laboratory. The mechanism has been built and tested to demonstrate TRL level 4. This paper describes the function of the system, mechanism design, lessons learned, and several challenges that were overcome.

  2. Refinement for Transition Systems with Responses

    Directory of Open Access Journals (Sweden)

    Marco Carbone

    2012-07-01

    Full Text Available Motivated by the response pattern for property specifications and applications within flexible workflow management systems, we report upon an initial study of modal and mixed transition systems in which the must transitions are interpreted as must eventually, and in which implementations can contain may behaviors that are resolved at run-time. We propose Transition Systems with Responses (TSRs as a suitable model for this study. We prove that TSRs correspond to a restricted class of mixed transition systems, which we refer to as the action-deterministic mixed transition systems. We show that TSRs allow for a natural definition of deadlocked and accepting states. We then transfer the standard definition of refinement for mixed transition systems to TSRs and prove that refinement does not preserve deadlock freedom. This leads to the proposal of safe refinements, which are those that preserve deadlock freedom. We exemplify the use of TSRs and (safe refinements on a small medication workflow.

  3. McDonald Observatory Planetary Search - A high precision stellar radial velocity survey for other planetary systems

    Science.gov (United States)

    Cochran, William D.; Hatzes, Artie P.

    1993-01-01

    The McDonald Observatory Planetary Search program surveyed a sample of 33 nearby F, G, and K stars since September 1987 to search for substellar companion objects. Measurements of stellar radial velocity variations to a precision of better than 10 m/s were performed as routine observations to detect Jovian planets in orbit around solar type stars. Results confirm the detection of a companion object to HD114762.

  4. Surface Systems R&D in NASA's Planetary Exploration Program

    Science.gov (United States)

    Weisbin, C.; Rodriguez, G.

    2000-01-01

    This paper reports on activities being supported by the Surface Systems Thrust of the NASA Cross Enterprise Technology Development Program, a research program whithin the NASA office of Space Science.

  5. Planet-planet scattering leads to tightly packed planetary systems

    OpenAIRE

    Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

    2009-01-01

    The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masse...

  6. On Determinism in Modal Transition Systems

    DEFF Research Database (Denmark)

    Benes, Nikola; Kretinsky, Jan; Larsen, Kim Guldstrand

    2009-01-01

    Modal transition systems (MTS) is a formalism which extends the classical notion of labelled transition systems by introducing transitions of two types: must transitions that have to be present in any implementation of the MTS and may transitions that are allowed but not required. The MTS framewo....... In the present article, we provide a comprehensive account of the MTS framework in the deterministic setting. We study a number of problems previously considered on MTS and point out to what extend we can expect better results under the restriction of determinism....

  7. Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions

    Science.gov (United States)

    Beck, R.; Arnold, J.; Gasch, M.; Stackpole, M.; Wercinski, R.; Venkatapathy, E.; Fan, W.; Thornton, J; Szalai, C.

    2012-01-01

    The Office of Chief Technologist (OCT), NASA has identified the need for research and technology development in part from NASAs Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASAs exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program (GCDP) is a primary avenue to achieve the Agencys 2011 strategic goal to Create the innovative new space technologies for our exploration, science, and economic future. In addition, recently released NASA Space Technology Roadmaps and Priorities, by the National Research Council (NRC) of the National Academy of Sciences stresses the need for NASA to invest in the very near term in specific EDL technologies. The report points out the following challenges (Page 2-38 of the pre-publication copy released on February 1, 2012): Mass to Surface: Develop the ability to deliver more payload to the destination. NASA's future missions will require ever-greater mass delivery capability in order to place scientifically significant instrument packages on distant bodies of interest, to facilitate sample returns from bodies of interest, and to enable human exploration of planets such as Mars. As the maximum mass that can be delivered to an entry interface is fixed for a given launch system and trajectory design, the mass delivered to the surface will require reductions in spacecraft structural mass more efficient, lighter thermal protection systems more efficient lighter propulsion systems and lighter, more efficient deceleration systems. Surface Access: Increase the ability to land at a variety of planetary locales and at a variety of times. Access to specific sites can be achieved via landing at a specific location(s) or transit from a single designated landing location, but it is currently infeasible to transit long distances and through extremely rugged terrain, requiring landing close to the site of

  8. Limb Darkening and Planetary Transits: Testing Center-to-limb Intensity Variations and Limb-darkening Directly from Model Stellar Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Neilson, Hilding R.; Lester, John B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); McNeil, Joseph T.; Ignace, Richard, E-mail: neilson@astro.utoronto.ca [Department of Physics and Astronomy, East Tennessee State University, Box 70652, Johnson City, TN 37614 (United States)

    2017-08-10

    The transit method, employed by Microvariability and Oscillation of Stars ( MOST ), Kepler , and various ground-based surveys has enabled the characterization of extrasolar planets to unprecedented precision. These results are precise enough to begin to measure planet atmosphere composition, planetary oblateness, starspots, and other phenomena at the level of a few hundred parts per million. However, these results depend on our understanding of stellar limb darkening, that is, the intensity distribution across the stellar disk that is sequentially blocked as the planet transits. Typically, stellar limb darkening is assumed to be a simple parameterization with two coefficients that are derived from stellar atmosphere models or fit directly. In this work, we revisit this assumption and compute synthetic planetary-transit light curves directly from model stellar atmosphere center-to-limb intensity variations (CLIVs) using the plane-parallel Atlas and spherically symmetric SAtlas codes. We compare these light curves to those constructed using best-fit limb-darkening parameterizations. We find that adopting parametric stellar limb-darkening laws leads to systematic differences from the more geometrically realistic model stellar atmosphere CLIV of about 50–100 ppm at the transit center and up to 300 ppm at ingress/egress. While these errors are small, they are systematic, and they appear to limit the precision necessary to measure secondary effects. Our results may also have a significant impact on transit spectra.

  9. The SOAPS project – Spin-orbit alignment of planetary systems

    Directory of Open Access Journals (Sweden)

    Hebb L.

    2013-04-01

    Full Text Available The wealth of information rendered by Kepler planets and planet candidates is indispensable for statistically significant studies of distinct planet populations, in both single and multiple systems. Empirical evidences suggest that Kepler's planet population shows different physical properties as compared to the bulk of known exoplanets. The SOAPS project, aims to shed light on Kepler's planets formation, their migration and architecture. By measuring v sini accurately for Kepler hosts with rotation periods measured from their high-precision light curves, we will assess the alignment of the planetary orbit with respect to the stellar spin axis. This degree of alignment traces the formation history and evolution of the planetary systems, and thus, allows to distinguish between different proposed migration theories. SOAPS will increase by a factor of 2 the number of spin-orbit alignment measurements pushing the parameters space down to the SuperEarth domain. Here we present our preliminary results.

  10. Concept of planetary gear system to control fluid mixture ratio

    Science.gov (United States)

    Mcgroarty, J. D.

    1966-01-01

    Mechanical device senses and corrects for fluid flow departures from the selected flow ratio of two fluids. This system has been considered for control of rocket engine propellant mixture control but could find use wherever control of the flow ratio of any two fluids is desired.

  11. Dynamical Stability of Imaged Planetary Systems in Formation: Application to HL Tau

    OpenAIRE

    Tamayo, Daniel; Triaud, Amaury H. M. J.; Menou, Kristen; Rein, Hanno

    2015-01-01

    A recent ALMA image revealed several concentric gaps in the protoplanetary disk surrounding the young star HL Tau. We consider the hypothesis that these gaps are carved by planets, and present a general framework for understanding the dynamical stability of such systems over typical disk lifetimes, providing estimates for the maximum planetary masses. We collect these easily evaluated constraints into a workflow that can help guide the design and interpretation of new observational campaigns ...

  12. Habitability in the Solar System and New Planetary Missions

    OpenAIRE

    Laine, Pauli Erik

    2013-01-01

    Definition of habitability depends on the organisms under consideration. One way to determine habitability of some environment is to compare its certain parameters to environments where extremophilic micro-organisms thrive on Earth. We can also define more common habitability criteria from the life as we know it. These criteria include basic elements, liquid water and an energy source. We know that some locations in our Solar System provide at least some of these limits and criteria. This art...

  13. The critical binary star separation for a planetary system origin of white dwarf pollution

    Science.gov (United States)

    Veras, Dimitri; Xu, Siyi; Rebassa-Mansergas, Alberto

    2018-01-01

    The atmospheres of between one quarter and one half of observed single white dwarfs in the Milky Way contain heavy element pollution from planetary debris. The pollution observed in white dwarfs in binary star systems is, however, less clear, because companion star winds can generate a stream of matter which is accreted by the white dwarf. Here, we (i) discuss the necessity or lack thereof of a major planet in order to pollute a white dwarf with orbiting minor planets in both single and binary systems, and (ii) determine the critical binary separation beyond which the accretion source is from a planetary system. We hence obtain user-friendly functions relating this distance to the masses and radii of both stars, the companion wind, and the accretion rate on to the white dwarf, for a wide variety of published accretion prescriptions. We find that for the majority of white dwarfs in known binaries, if pollution is detected, then that pollution should originate from planetary material.

  14. System for Packaging Planetary Samples for Return to Earth

    Science.gov (United States)

    Badescu, Mircea; Bar-Cohen, Yoseph; Backes, paul G.; Sherrit, Stewart; Bao, Xiaoqi; Scott, James S.

    2010-01-01

    A system is proposed for packaging material samples on a remote planet (especially Mars) in sealed sample tubes in preparation for later return to Earth. The sample tubes (Figure 1) would comprise (1) tubes initially having open tops and closed bottoms; (2) small, bellows-like collapsible bodies inside the tubes at their bottoms; and (3) plugs to be eventually used to close the tops of the tubes. The top inner surface of each tube would be coated with solder. The side of each plug, which would fit snugly into a tube, would feature a solder-filled ring groove. The system would include equipment for storing, manipulating, filling, and sealing the tubes. The containerization system (see Figure 2) will be organized in stations and will include: the storage station, the loading station, and the heating station. These stations can be structured in circular or linear pattern to minimize the manipulator complexity, allowing for compact design and mass efficiency. The manipulation of the sample tube between stations is done by a simple manipulator arm. The storage station contains the unloaded sample tubes and the plugs before sealing as well as the sealed sample tubes with samples after loading and sealing. The chambers at the storage station also allow for plug insertion into the sample tube. At the loading station the sample is poured or inserted into the sample tube and then the tube is topped off. At the heating station the plug is heated so the solder ring melts and seals the plug to the sample tube. The process is performed as follows: Each tube is filled or slightly overfilled with sample material and the excess sample material is wiped off the top. Then, the plug is inserted into the top section of the tube packing the sample material against the collapsible bellowslike body allowing the accommodation of the sample volume. The plug and the top of the tube are heated momentarily to melt the solder in order to seal the tube.

  15. Delivering power system transition in China

    International Nuclear Information System (INIS)

    Yuan Jiahai; Xu Yan; Hu Zhaoguang

    2012-01-01

    This paper studies the transition to low carbon power systems in China. The methodology is built on the newly developed multi-level perspective (MLP) transitions, as well as literature on innovation systems. Three lines of thought on the transition process are integrated to probe the possible transition pathways in China's power sector. Five transition pathways, namely reproduction, transformation, substitution, reconfiguration, de-alignment/re-alignment and reconfiguration, with their possible technology options are presented. The requirements for a smart grid in the socio-technical transition process are addressed within the MLP framework. The paper goes further to propose an interactive framework for low carbon transition management in China. Representative technology options are appraised by employing innovation theory to demonstrate the logic of policy design within the framework. The work presented in this paper will be useful in informing policy-makers and other stakeholders in China and it may prove to be a valuable reference for other countries in energy transition management. - Highlights: ► The transition to low carbon power systems is studied from a multi-level perspective. ► Transition pathways with possible technology options are presented. ► An interactive framework is proposed for managing this transition. ► Representative technology options are appraised within the framework to show the logic of policy design.

  16. An extrasolar planetary system with three Neptune-mass planets.

    Science.gov (United States)

    Lovis, Christophe; Mayor, Michel; Pepe, Francesco; Alibert, Yann; Benz, Willy; Bouchy, François; Correia, Alexandre C M; Laskar, Jacques; Mordasini, Christoph; Queloz, Didier; Santos, Nuno C; Udry, Stéphane; Bertaux, Jean-Loup; Sivan, Jean-Pierre

    2006-05-18

    Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.

  17. MarsVac: Pneumatic Sampling System for Planetary Exploration

    Science.gov (United States)

    Zacny, K.; Mungas, G.; Chu, P.; Craft, J.; Davis, K.

    2008-12-01

    We are proposing a Mars Sample Return scheme whereby a sample of regolith is acquired directly into a Mars Ascent Vehicle using a pneumatic system. Unlike prior developments that used suction to collect fines, the proposed system uses positive pressure to move the regolith. We envisage 3 pneumatic tubes to be embedded inside the 3 legs of the lander. Upon landing, the legs will burry themselves into the regolith and the tubes will fill up with regolith. With one puff of gas, the regolith can be lifted into a sampling chamber onboard of the Mars Ascent Vehicle. An additional chamber can be opened to acquire atmospheric gas and dust. The entire MSR will require 1) an actuator to open/close sampling chamber and 2) a valve to open gas cylinder. In the most recent study related to lunar excavation and funded under the NASA SBIR program we have shown that it is possible lift over 3000 grams of soil with only 1 gram of gas at 1atm. Tests conducted under Mars atmospheric pressure conditions (5 torr). In September of 2008, we will be performing tests at 1/6thg (Moon) and 1/3g (Mars) to determine mass lifting efficiencies in reduced gravities.

  18. Predicting Instability Timescales in Closely-Packed Planetary Systems

    Science.gov (United States)

    Tamayo, Daniel; Hadden, Samuel; Hussain, Naireen; Silburt, Ari; Gilbertson, Christian; Rein, Hanno; Menou, Kristen

    2018-04-01

    Many of the multi-planet systems discovered around other stars are maximally packed. This implies that simulations with masses or orbital parameters too far from the actual values will destabilize on short timescales; thus, long-term dynamics allows one to constrain the orbital architectures of many closely packed multi-planet systems. A central challenge in such efforts is the large computational cost of N-body simulations, which preclude a full survey of the high-dimensional parameter space of orbital architectures allowed by observations. I will present our recent successes in training machine learning models capable of reliably predicting orbital stability a million times faster than N-body simulations. By engineering dynamically relevant features that we feed to a gradient-boosted decision tree algorithm (XGBoost), we are able to achieve a precision and recall of 90% on a holdout test set of N-body simulations. This opens a wide discovery space for characterizing new exoplanet discoveries and for elucidating how orbital architectures evolve through time as the next generation of spaceborne exoplanet surveys prepare for launch this year.

  19. Dynamic Response of a Planetary Gear System Using a Finite Element/Contact Mechanics Model

    Science.gov (United States)

    Parker, Robert G.; Agashe, Vinayak; Vijayakar, Sandeep M.

    2000-01-01

    The dynamic response of a helicopter planetary gear system is examined over a wide range of operating speeds and torques. The analysis tool is a unique, semianalytical finite element formulation that admits precise representation of the tooth geometry and contact forces that are crucial in gear dynamics. Importantly, no a priori specification of static transmission error excitation or mesh frequency variation is required; the dynamic contact forces are evaluated internally at each time step. The calculated response shows classical resonances when a harmonic of mesh frequency coincides with a natural frequency. However, peculiar behavior occurs where resonances expected to be excited at a given speed are absent. This absence of particular modes is explained by analytical relationships that depend on the planetary configuration and mesh frequency harmonic. The torque sensitivity of the dynamic response is examined and compared to static analyses. Rotation mode response is shown to be more sensitive to input torque than translational mode response.

  20. Nonlinear Dynamic Analysis and Optimization of Closed-Form Planetary Gear System

    Directory of Open Access Journals (Sweden)

    Qilin Huang

    2013-01-01

    Full Text Available A nonlinear purely rotational dynamic model of a multistage closed-form planetary gear set formed by two simple planetary stages is proposed in this study. The model includes time-varying mesh stiffness, excitation fluctuation and gear backlash nonlinearities. The nonlinear differential equations of motion are solved numerically using variable step-size Runge-Kutta. In order to obtain function expression of optimization objective, the nonlinear differential equations of motion are solved analytically using harmonic balance method (HBM. Based on the analytical solution of dynamic equations, the optimization mathematical model which aims at minimizing the vibration displacement of the low-speed carrier and the total mass of the gear transmission system is established. The optimization toolbox in MATLAB program is adopted to obtain the optimal solution. A case is studied to demonstrate the effectiveness of the dynamic model and the optimization method. The results show that the dynamic properties of the closed-form planetary gear transmission system have been improved and the total mass of the gear set has been decreased significantly.

  1. Phase transition in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

    2000-01-01

    The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)

  2. Phase transition in finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph.; Duflot, V. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Duflot, V.; Gulminelli, F. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France)

    2000-07-01

    The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)

  3. Absorbing Gas around the WASP-12 Planetary System

    Science.gov (United States)

    Fossati, L.; Ayres, T. R.; Haswell, C. A.; Bohlender, D.; Kochukhov, O.; Flöer, L.

    2013-04-01

    Near-UV observations of the planet host star WASP-12 uncovered the apparent absence of the normally conspicuous core emission of the Mg II h and k resonance lines. This anomaly could be due either to (1) a lack of stellar activity, which would be unprecedented for a solar-like star of the imputed age of WASP-12 or (2) extrinsic absorption, from the intervening interstellar medium (ISM) or from material within the WASP-12 system itself, presumably ablated from the extreme hot Jupiter WASP-12 b. HIRES archival spectra of the Ca II H and K lines of WASP-12 show broad depressions in the line cores, deeper than those of other inactive and similarly distant stars and similar to WASP-12's Mg II h and k line profiles. We took high-resolution ESPaDOnS and FIES spectra of three early-type stars within 20' of WASP-12 and at similar distances, which show the ISM column is insufficient to produce the broad Ca II depression observed in WASP-12. The EBHIS H I column density map supports and strengthens this conclusion. Extrinsic absorption by material local to the WASP-12 system is therefore the most likely cause of the line core anomalies. Gas escaping from the heavily irradiated planet could form a stable and thick circumstellar disk/cloud. The anomalously low stellar activity index (log R^{{\\prime }}_{HK}) of WASP-12 is evidently a direct consequence of the extra core absorption, so similar HK index deficiencies might signal the presence of translucent circumstellar gas around other stars hosting evaporating planets. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Rechereche Scientifique of France, and the University of Hawaii. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del

  4. NASA's Solar System Treks: Online Portals for Planetary Mapping and Modeling

    Science.gov (United States)

    Day, B. H.; Law, E.

    2017-12-01

    NASA's Solar System Treks are a suite of web-based of lunar and planetary mapping and modeling portals providing interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to access mapped lunar data products from past and current missions for the Moon, Mars, Vesta, and more. New portals for additional planetary bodies are being planned. This presentation will recap significant enhancements to these toolsets during the past year and look ahead to future features and releases. Moon Trek is a new portal replacing its predecessor, the Lunar Mapping and Modeling Portal (LMMP), that significantly upgrades and builds upon the capabilities of LMMP. It features greatly improved navigation, 3D visualization, fly-overs, performance, and reliability. Additional data products and tools continue to be added. These include both generalized products as well as polar data products specifically targeting potential sites for NASA's Resource Prospector mission as well as for missions being planned by NASA's international partners. The latest release of Mars Trek includes new tools and data products requested by NASA's Planetary Science Division to support site selection and analysis for Mars Human Landing Exploration Zone Sites. Also being given very high priority by NASA Headquarters is Mars Trek's use as a means to directly involve the public in upcoming missions, letting them explore the areas the agency is focusing upon, understand what makes these sites so fascinating, follow the selection process, and get caught up in the excitement of exploring Mars. Phobos Trek, the latest effort in the Solar System Treks suite, is being developed in coordination with the International Phobos/Deimos Landing Site Working Group, with landing site selection and analysis for JAXA's MMX mission as a primary driver.

  5. NASA's Solar System Treks: Online Portals for Planetary Mapping and Modeling

    Science.gov (United States)

    Day, Brian

    2017-01-01

    NASA's Solar System Treks are a suite of web-based of lunar and planetary mapping and modeling portals providing interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to access mapped lunar data products from past and current missions for the Moon, Mars, Vesta, and more. New portals for additional planetary bodies are being planned. This presentation will recap significant enhancements to these toolsets during the past year and look ahead to future features and releases. Moon Trek is a new portal replacing its predecessor, the Lunar Mapping and Modeling Portal (LMMP), that significantly upgrades and builds upon the capabilities of LMMP. It features greatly improved navigation, 3D visualization, fly-overs, performance, and reliability. Additional data products and tools continue to be added. These include both generalized products as well as polar data products specifically targeting potential sites for NASA's Resource Prospector mission as well as for missions being planned by NASA's international partners. The latest release of Mars Trek includes new tools and data products requested by NASA's Planetary Science Division to support site selection and analysis for Mars Human Landing Exploration Zone Sites. Also being given very high priority by NASA Headquarters is Mars Trek's use as a means to directly involve the public in upcoming missions, letting them explore the areas the agency is focusing upon, understand what makes these sites so fascinating, follow the selection process, and get caught up in the excitement of exploring Mars. Phobos Trek, the latest effort in the Solar System Treks suite, is being developed in coordination with the International Phobos/Deimos Landing Site Working Group, with landing site selection and analysis for JAXA's MMX (Martian Moons eXploration) mission as a primary driver.

  6. Planetary Society

    Science.gov (United States)

    Murdin, P.

    2000-11-01

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

  7. Financial system development in transition economies

    NARCIS (Netherlands)

    Hermes, C.L.M.; Lensink, B.W.

    This paper provides an overview of the major issues with respect to financial system development in transition economies, which were discussed at a conference in Groningen, the Netherlands, December 1997. After a brief remark on the role of financial system design during economic transition, the

  8. Stimulating transitions towards sustainable farming systems

    NARCIS (Netherlands)

    Elzen, B.; Barbier, M.; Cerf, M.; Grin, J.

    2012-01-01

    How can the dynamics of the agro-food sector in the long run be addressed? We argue that sustainable agro-food systems cannot be developed through a simple improvement of existing systems, but will require a transition. Therefore, we focus on how transitions to sustainability could be initiated and

  9. NASA's Planetary Data System: Support for the Delivery of Derived Data Sets at the Atmospheres Node

    Science.gov (United States)

    Chanover, Nancy J.; Beebe, Reta; Neakrase, Lynn; Huber, Lyle; Rees, Shannon; Hornung, Danae

    2015-11-01

    NASA’s Planetary Data System is charged with archiving electronic data products from NASA planetary missions that are sponsored by NASA’s Science Mission Directorate. This archive, currently organized by science disciplines, uses standards for describing and storing data that are designed to enable future scientists who are unfamiliar with the original experiments to analyze the data, and to do this using a variety of computer platforms, with no additional support. These standards address the data structure, description contents, and media design. The new requirement in the NASA ROSES-2015 Research Announcement to include a Data Management Plan will result in an increase in the number of derived data sets that are being delivered to the PDS. These data sets may come from the Planetary Data Archiving, Restoration and Tools (PDART) program, other Data Analysis Programs (DAPs) or be volunteered by individuals who are publishing the results of their analysis. In response to this increase, the PDS Atmospheres Node is developing a set of guidelines and user tools to make the process of archiving these derived data products more efficient. Here we provide a description of Atmospheres Node resources, including a letter of support for the proposal stage, a communication schedule for the planned archive effort, product label samples and templates in extensible markup language (XML), documentation templates, and validation tools necessary for producing a PDS4-compliant derived data bundle(s) efficiently and accurately.

  10. Earth analog image digitization of field, aerial, and lab experiment studies for Planetary Data System archiving.

    Science.gov (United States)

    Williams, D. A.; Nelson, D. M.

    2017-12-01

    A portion of the earth analog image archive at the Ronald Greeley Center for Planetary Studies (RGCPS)-the NASA Regional Planetary Information Facility at Arizona State University-is being digitized and will be added to the Planetary Data System (PDS) for public use. This will be a first addition of terrestrial data to the PDS specifically for comparative planetology studies. Digitization is separated into four tasks. First is the scanning of aerial photographs of volcanic and aeolian structures and flows. The second task is to scan field site images taken from ground and low-altitude aircraft of volcanic structures, lava flows, lava tubes, dunes, and wind streaks. The third image set to be scanned includes photographs of lab experiments from the NASA Planetary Aeolian Laboratory wind tunnels, vortex generator, and of wax models. Finally, rare NASA documents are being scanned and formatted as PDF files. Thousands of images are to be scanned for this project. Archiving of the data will follow the PDS4 standard, where the entire project is classified as a single bundle, with individual subjects (i.e., the Amboy Crater volcanic structure in the Mojave Desert of California) as collections. Within the collections, each image is considered a product, with a unique ID and associated XML document. Documents describing the image data, including the subject and context, will be included with each collection. Once complete, the data will be hosted by a PDS data node and available for public search and download. As one of the first earth analog datasets to be archived by the PDS, this project could prompt the digitizing and making available of historic datasets from other facilities for the scientific community.

  11. An Overview of the Planetary Data System Roadmap Study for 2017 - 2026

    Science.gov (United States)

    Morgan, Thomas H.; McNutt, Ralph L.; Gaddis, Lisa; Law, Emily; Beyer, Ross A.; Crombie, Kate; Ebel, Denton; Ghosh, Amitahba; Grayzeck, Edwin J.; Paganelli, Flora; Raugh, Anne C.; Stein, Thomas; Tiscareno, Matthew S.; Weber, Renee; E Banks, Maria; Powell, Kathryn

    2017-10-01

    NASA’s Planetary Data System (PDS) is the formal archive of >1.2 petabytes of data from planetary exploration, science, and research. Initiated in 1989 to address an overall lack of attention to mission data documentation, access, and archiving, the PDS has since evolved into an online collection of digital data managed and served by a federation of 6 science discipline nodes and 2 technical support nodes. Several ad-hoc mission-oriented data nodes also provide complex data interfaces and access for the duration of their missions.The new PDS Roadmap Study for 2017-2026 involved 15 planetary science community members who collectively prepared a report summarizing the results of an intensive examination of the current state of the PDS and its organization, management, practices, and data holdings (https://pds.jpl.nasa.gov/roadmap/PlanetaryDataSystemRMS17-26_20jun17.pdf). The report summarizes PDS history, its functions and characteristics, and its present form; also included are extensive references and documentary appendices. The report recognizes that as a complex evolving system, the PDS must respond to new pressures and opportunities. The report provides details on challenges now facing the PDS, 19 detailed findings and suggested remediations that could be used to respond to these findings, and a summary of the potential future of planetary data archiving. These findings cover topics such as user needs and expectations, data usability and discoverability (i.e., metadata, data access, documentation, and training), tools and file formats, use of current information technologies, and responses to increases in data volume, variety, complexity, and number of data providers. In addition, the study addresses the possibility of archiving software, laboratory data, and physical samples. Finally, the report discusses the current structure and governance of PDS and the impact of this on how archive growth, technology, and new developments are enabled and managed within

  12. Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing

    Science.gov (United States)

    Samareh, Jamshid A.

    2011-01-01

    Systems analysis of a planetary entry (SAPE), descent, and landing (EDL) is a multidisciplinary activity in nature. SAPE improves the performance of the systems analysis team by automating and streamlining the process, and this improvement can reduce the errors that stem from manual data transfer among discipline experts. SAPE is a multidisciplinary tool for systems analysis of planetary EDL for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. It performs EDL systems analysis for any planet, operates cross-platform (i.e., Windows, Mac, and Linux operating systems), uses existing software components and open-source software to avoid software licensing issues, performs low-fidelity systems analysis in one hour on a computer that is comparable to an average laptop, and keeps discipline experts in the analysis loop. SAPE uses Python, a platform-independent, open-source language, for integration and for the user interface. Development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE currently includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and interface for structural sizing.

  13. Trilogy, a planetary geodesy mission concept for measuring the expansion of the solar system

    Science.gov (United States)

    Smith, David E.; Zuber, Maria T.; Mazarico, Erwan; Genova, Antonio; Neumann, Gregory A.; Sun, Xiaoli; Torrence, Mark H.; Mao, Dan-dan

    2018-04-01

    The scale of the solar system is slowly changing, likely increasing as a result of solar mass loss, with additional change possible if there is a secular variation of the gravitational constant, G. The measurement of the change of scale could provide insight into the past and the future of the solar system, and in addition a better understanding of planetary motion and fundamental physics. Estimates for the expansion of the scale of the solar system are of order 1.5 cm year-1 AU-1, which over several years is an observable quantity with present-day laser ranging systems. This estimate suggests that laser measurements between planets could provide an accurate estimate of the solar system expansion rate. We examine distance measurements between three bodies in the inner solar system - Earth's Moon, Mars and Venus - and outline a mission concept for making the measurements. The concept involves placing spacecraft that carry laser ranging transponders in orbit around each body and measuring the distances between the three spacecraft over a period of several years. The analysis of these range measurements would allow the co-estimation of the spacecraft orbit, planetary ephemerides, other geophysical parameters related to the constitution and dynamics of the central bodies, and key geodetic parameters related to the solar system expansion, the Sun, and theoretical physics.

  14. Trilogy, a Planetary Geodesy Mission Concept for Measuring the Expansion of the Solar System.

    Science.gov (United States)

    Smith, David E; Zuber, Maria T; Mazarico, Erwan; Genova, Antonio; Neumann, Gregory A; Sun, Xiaoli; Torrence, Mark H; Mao, Dan-Dan

    2018-04-01

    The scale of the solar system is slowly changing, likely increasing as a result of solar mass loss, with additional change possible if there is a secular variation of the gravitational constant, G . The measurement of the change of scale could provide insight into the past and the future of the solar system, and in addition a better understanding of planetary motion and fundamental physics. Estimates for the expansion of the scale of the solar system are of order 1.5 cm year -1 AU -1 , which over several years is an observable quantity with present-day laser ranging systems. This estimate suggests that laser measurements between planets could provide an accurate estimate of the solar system expansion rate. We examine distance measurements between three bodies in the inner solar system -- Earth's Moon, Mars and Venus -- and outline a mission concept for making the measurements. The concept involves placing spacecraft that carry laser ranging transponders in orbit around each body and measuring the distances between the three spacecraft over a period of several years. The analysis of these range measurements would allow the co-estimation of the spacecraft orbit, planetary ephemerides, other geophysical parameters related to the constitution and dynamics of the central bodies, and key geodetic parameters related to the solar system expansion, the Sun, and theoretical physics.

  15. Transition Theory – Sustainable Transition of Socio-Technical Systems

    DEFF Research Database (Denmark)

    Søndergård, Bent; Holm, Jesper; Stauning, Inger

    2015-01-01

    Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction......Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction...

  16. PC Software graphics tool for conceptual design of space/planetary electrical power systems

    Science.gov (United States)

    Truong, Long V.

    1995-01-01

    This paper describes the Decision Support System (DSS), a personal computer software graphics tool for designing conceptual space and/or planetary electrical power systems. By using the DSS, users can obtain desirable system design and operating parameters, such as system weight, electrical distribution efficiency, and bus power. With this tool, a large-scale specific power system was designed in a matter of days. It is an excellent tool to help designers make tradeoffs between system components, hardware architectures, and operation parameters in the early stages of the design cycle. The DSS is a user-friendly, menu-driven tool with online help and a custom graphical user interface. An example design and results are illustrated for a typical space power system with multiple types of power sources, frequencies, energy storage systems, and loads.

  17. PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

    2010-01-01

    We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ('planetesimals'). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M + from 10 to 20 AU. For large planet masses (M ∼> M Sat ), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a ∼ -1 and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with ∼ Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive

  18. YOUNG PLANETARY NEBULAE: HUBBLE SPACE TELESCOPE IMAGING AND A NEW MORPHOLOGICAL CLASSIFICATION SYSTEM

    International Nuclear Information System (INIS)

    Sahai, Raghvendra; Villar, Gregory G.; Morris, Mark R.

    2011-01-01

    Using Hubble Space Telescope images of 119 young planetary nebulae (PNs), most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of PNs. Unlike previous classification studies, we have focused primarily on young PNs rather than all PNs, because the former best show the influences or symmetries imposed on them by the dominant physical processes operating at the first and primary stage of the shaping process. Older PNs develop instabilities, interact with the ambient interstellar medium, and are subject to the passage of photoionization fronts, all of which obscure the underlying symmetries and geometries imposed early on. Our classification system is designed to suffer minimal prejudice regarding the underlying physical causes of the different shapes and structures seen in our PN sample, however, in many cases, physical causes are readily suggested by the geometry, along with the kinematics that have been measured in some systems. Secondary characteristics in our system, such as ansae, indicate the impact of a jet upon a slower-moving, prior wind; a waist is the signature of a strong equatorial concentration of matter, whether it be outflowing or in a bound Keplerian disk, and point symmetry indicates a secular trend, presumably precession, in the orientation of the central driver of a rapid, collimated outflow.

  19. Planetary engineering

    Science.gov (United States)

    Pollack, James B.; Sagan, Carl

    1991-01-01

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  20. Planetary engineering

    Science.gov (United States)

    Pollack, James B.; Sagan, Carl

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  1. DISK-PLANETS INTERACTIONS AND THE DIVERSITY OF PERIOD RATIOS IN KEPLER'S MULTI-PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Baruteau, Clement; Papaloizou, John C. B.

    2013-01-01

    The Kepler mission is dramatically increasing the number of planets known in multi-planetary systems. Many adjacent planets have orbital period ratios near resonant values, with a tendency to be larger than required for exact first-order mean-motion resonances. This feature has been shown to be a natural outcome of orbital circularization of resonant planetary pairs due to star-planet tidal interactions. However, this feature holds in multi-planetary systems with periods longer than 10 days, in which tidal circularization is unlikely to provide efficient divergent evolution of the planets' orbits to explain these orbital period ratios. Gravitational interactions between planets and their parent protoplanetary disk may instead provide efficient divergent evolution. For a planet pair embedded in a disk, we show that interactions between a planet and the wake of its companion can reverse convergent migration and significantly increase the period ratio from a near-resonant value. Divergent evolution due to wake-planet interactions is particularly efficient when at least one of the planets opens a partial gap around its orbit. This mechanism could help account for the diversity of period ratios in Kepler's multiple systems from super-Earth to sub-Jovian planets with periods greater than about 10 days. Diversity is also expected for pairs of planets massive enough to merge their gap. The efficiency of wake-planet interactions is then much reduced, but convergent migration may stall with a variety of period ratios depending on the density structure in the common gap. This is illustrated for the Kepler-46 system, for which we reproduce the period ratio of Kepler-46b and c

  2. Extending Modal Transition Systems with Structured Labels

    DEFF Research Database (Denmark)

    Bauer, Sebastian S.; Juhl, Line; Larsen, Kim Guldstrand

    2012-01-01

    We introduce a novel formalism of label-structured modal transition systems that combines the classical may/must modalities on transitions with structured labels that represent quantitative aspects of the model. On the one hand, the specification formalism is general enough to include models like...... weighted modal transition systems and allows the system developers to employ more complex label refinement than in the previously studied theories. On the other hand, the formalism maintains the desirable properties required by any specification theory supporting compositional reasoning. In particular, we...

  3. RESONANCES REQUIRED: DYNAMICAL ANALYSIS OF THE 24 Sex AND HD 200964 PLANETARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G., E-mail: rob@phys.unsw.edu.au [Department of Astrophysics, School of Physics, Faculty of Science, University of New South Wales, NSW 2052 (Australia)

    2012-12-20

    We perform several suites of highly detailed dynamical simulations to investigate the architectures of the 24 Sextantis and HD 200964 planetary systems. The best-fit orbital solution for the two planets in the 24 Sex system places them on orbits with periods that lie very close to 2:1 commensurability, while that for the HD 200964 system places the two planets therein in orbits whose periods lie close to a 4:3 commensurability. In both cases, the proposed best-fit orbits are mutually crossing-a scenario that is only dynamically feasible if the planets are protected from close encounters by the effects of mutual mean-motion resonance (MMR). Our simulations reveal that the best-fit orbits for both systems lie within narrow islands of dynamical stability, and are surrounded by much larger regions of extreme instability. As such, we show that the planets are only feasible if they are currently trapped in mutual MMR-the 2:1 resonance in the case of 24 Sex b and c, and the 4:3 resonance in the case of HD 200964 b and c. In both cases, the region of stability is strongest and most pronounced when the planetary orbits are mutually coplanar. As the inclination of planet c with respect to planet b is increased, the stability of both systems rapidly collapses.

  4. System concepts and design examples for optical communication with planetary spacecraft

    Science.gov (United States)

    Lesh, James R.

    Systems concepts for optical communication with future deep-space (planetary) spacecraft are described. These include not only the optical transceiver package aboard the distant spacecraft, but the earth-vicinity optical-communications receiving station as well. Both ground-based, and earth-orbiting receivers are considered. Design examples for a number of proposed or potential deep-space missions are then presented. These include an orbital mission to Saturn, a Lander and Rover mission to Mars, and an astronomical mission to a distance of 1000 astronomical units.

  5. Conceptual definition of a 50-100 kWe NEP system for planetary science missions

    Science.gov (United States)

    Friedlander, Alan

    1993-01-01

    The Phase 1 objective of this project is to assess the applicability of a common Nuclear Electric Propulsion (NEP) flight system of the 50-100 kWe power class to meet the advanced transportation requirements of a suite of planetary science (robotic) missions, accounting for differences in mission-specific payloads and delivery requirements. The candidate missions are as follows: (1) Comet Nucleus Sample Return; (2) Multiple Mainbelt Asteroid Rendezvous; (3) Jupiter Grand Tour (Galilean satellites and magnetosphere); (4) Uranus Orbiter/Probe (atmospheric entry and landers); (5) Neptune Orbiter/Probe (atmospheric entry and landers); and (6) Pluto-Charon Orbiter/Lander. The discussion is presented in vugraph form.

  6. Microvax-based data management and reduction system for the regional planetary image facilities

    Science.gov (United States)

    Arvidson, R.; Guinness, E.; Slavney, S.; Weiss, B.

    1987-01-01

    Presented is a progress report for the Regional Planetary Image Facilities (RPIF) prototype image data management and reduction system being jointly implemented by Washington University and the USGS, Flagstaff. The system will consist of a MicroVAX with a high capacity (approx 300 megabyte) disk drive, a compact disk player, an image display buffer, a videodisk player, USGS image processing software, and SYSTEM 1032 - a commercial relational database management package. The USGS, Flagstaff, will transfer their image processing software including radiometric and geometric calibration routines, to the MicroVAX environment. Washington University will have primary responsibility for developing the database management aspects of the system and for integrating the various aspects into a working system.

  7. THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS

    International Nuclear Information System (INIS)

    Debes, John H.; Walsh, Kevin J.; Stark, Christopher

    2012-01-01

    It has long been suspected that metal-polluted white dwarfs (types DAZ, DBZ, and DZ) and white dwarfs with dusty disks possess planetary systems, but a specific physical mechanism by which planetesimals are perturbed close to a white dwarf has not yet been fully posited. In this paper, we demonstrate that mass loss from a central star during post-main-sequence evolution can sweep planetesimals into interior mean motion resonances with a single giant planet. These planetesimals are slowly removed through chaotic excursions of eccentricity that in time create radial orbits capable of tidally disrupting the planetesimal. Numerical N-body simulations of the solar system show that a sufficient number of planetesimals are perturbed to explain white dwarfs with both dust and metal pollution, provided other white dwarfs have more massive relic asteroid belts. Our scenario requires only one Jupiter-sized planet and a sufficient number of asteroids near its 2:1 interior mean motion resonance. Finally, we show that once a planetesimal is perturbed into a tidal crossing orbit, it will become disrupted after the first pass of the white dwarf, where a highly eccentric stream of debris forms the main reservoir for dust-producing collisions. These simulations, in concert with observations of white dwarfs, place interesting limits on the frequency of planetary systems around main-sequence stars, the frequency of planetesimal belts, and the probability that dust may obscure future terrestrial planet finding missions.

  8. A wideband optical monitor for a planetary-rotation coating-system

    International Nuclear Information System (INIS)

    Campanelli, M.B.; Smith, D.J.

    1998-01-01

    A substrate-specific, through-planet, wideband optical coating monitor is being developed to increase production yield and the understanding of physical vapor deposition (PVD) coatings fabricated in the Optical Manufacturing Laboratory at the University of Rochester's Laboratory for Laser Energetics. In-situ wideband optical monitoring of planetary rotation systems allows direct monitoring of large, expensive substrates with complex layering schemes. The optical monitor discussed here is under development for coating several large (e.g., 80.7 x 41.7 x 9.0 cm) polarizers for the National Ignition Facility. Wideband optical monitoring of the production substrates is used in concert with an array of crystal monitors for process control, film parameter evaluation, and error detection with associated design reoptimization. The geometry of a planetary rotation system, which produces good uniformity across large substrates, makes optical monitoring more difficult. Triggering and timing techniques for data acquisition become key to the process because the optical coating is available only intermittently for monitoring. Failure to properly consider the effects of the system dynamics during data retrieval and processing may result in significant decreases in the spectral data's reliability. Improved data accuracy allows better determination of film thicknesses, indices, and inhomogeneities and enables in-situ error detection for design reoptimization

  9. PREDICTING THE CONFIGURATION OF A PLANETARY SYSTEM: KOI-152 OBSERVED BY KEPLER

    International Nuclear Information System (INIS)

    Wang Su; Ji Jianghui; Zhou Jilin

    2012-01-01

    The recent Kepler discovery of KOI-152 reveals a system of three hot super-Earth candidates that are in or near a 4:2:1 mean motion resonance. It is unlikely that they formed in situ; the planets probably underwent orbital migration during the formation and evolution process. The small semimajor axes of the three planets suggest that migration stopped at the inner edge of the primordial gas disk. In this paper, we focus on the influence of migration halting mechanisms, including migration 'dead zones', and inner truncation by the stellar magnetic field. We show that the stellar accretion rate, stellar magnetic field, and the speed of migration in the protoplanetary disk are the main factors affecting the final configuration of KOI-152. Our simulations suggest that three planets may be around a star with low star accretion rate or with high magnetic field. On the other hand, slow type I migration, which decreases to one-tenth of the linear analysis results, favors forming the configuration of KOI-152. Under such a formation scenario, the planets in the system are not massive enough to open gaps in the gas disk. The upper limits of the planetary masses are estimated to be about 15, 19, and 24 M ⊕ , respectively. Our results are also indicative of the near Laplacian configurations that are quite common in planetary systems.

  10. Biological life support systems for a Mars mission planetary base: Problems and prospects

    Science.gov (United States)

    Tikhomirov, A. A.; Ushakova, S. A.; Kovaleva, N. P.; Lamaze, B.; Lobo, M.; Lasseur, Ch.

    The study develops approaches to designing biological life support systems for the Mars mission - for the flight conditions and for a planetary base - using experience of the Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences (IBP SB RAS) with the Bios-3 system and ESA's experience with the MELISSA program. Variants of a BLSS based on using Chlorella and/or Spirulina and higher plants for the flight period of the Mars mission are analyzed. It is proposed constructing a BLSS with a closed-loop material cycle for gas and water and for part of human waste. A higher-plant-based BLSS with the mass exchange loop closed to various degrees is proposed for a Mars planetary base. Various versions of BLSS configuration and degree of closure of mass exchange are considered, depending on the duration of the Mars mission, the diet of the crew, and some other conditions. Special consideration is given to problems of reliability and sustainability of material cycling in BLSS, which are related to production of additional oxygen inside the system. Technologies of constructing BLSS of various configurations are proposed and substantiated. Reasons are given for using physicochemical methods in BLSS as secondary tools both during the flight and the stay on Mars.

  11. ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Lissauer, Jack J.; Jenkins, Jon M.; Borucki, William J.; Bryson, Stephen T.; Howell, Steve B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Ragozzine, Darin; Holman, Matthew J.; Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Fabrycky, Daniel C.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, Batavia, IL 60510 (United States); Ford, Eric B. [211 Bryant Space Science Center, University of Florida, Gainesville, FL 32611 (United States); Shporer, Avi [Las Cumbres Observatory Global Telescope Network, Santa Barbara, CA 93117 (United States); Rowe, Jason F.; Quintana, Elisa V.; Caldwell, Douglas A. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Ciardi, David [Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Dunham, Edward W. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Gautier, Thomas N. III, E-mail: Jack.Lissauer@nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); and others

    2011-11-01

    About one-third of the {approx}1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.

  12. FINANCIAL SYSTEM STRUCTURE AND STABILITY DURING TRANSITION

    Directory of Open Access Journals (Sweden)

    Firtescu Bogdan

    2012-07-01

    Full Text Available The process of transition from socialist economy to market economy was not considered an end in itself, but a necessity, and standing proof to achieve high levels of sustainable development. All former socialist countries are characterized by an early transition recession transformation result of the restructuring, loss of markets, tough competition from foreign products, best quality, or in other cases cheaper. To express the financial system structure in transition we take into discussion data that reflects representatives mutations and restructuring in Central and Eastern European countries, such Bulgaria, Czech Republic, Hungary, Poland and Romania. For all countries we show some important changes of financial system during transition and construct an image matrix that illustrates important indicators of financial system structure and their adjustment.

  13. A Modular, Reusable Latch and Decking System for Securing Payloads During Launch and Planetary Surface Transport

    Science.gov (United States)

    Doggett, William R.; Dorsey, John T.; Jones, Thomas C.; King, Bruce D.; Mikulas, Martin M.

    2011-01-01

    Efficient handling of payloads destined for a planetary surface, such as the moon or mars, requires robust systems to secure the payloads during transport on the ground, in space and on the planetary surface. In addition, mechanisms to release the payloads need to be reliable to ensure successful transfer from one vehicle to another. An efficient payload handling strategy must also consider the devices available to support payload handling. Cranes used for overhead lifting are common to all phases of payload handling on Earth. Similarly, both recent and past studies have demonstrated that devices with comparable functionality will be needed to support lunar outpost operations. A first generation test-bed of a new high performance device that provides the capabilities of both a crane and a robotic manipulator, the Lunar Surface Manipulation System (LSMS), has been designed, built and field tested and is available for use in evaluating a system to secure payloads to transportation vehicles. A payload handling approach must address all phases of payload management including: ground transportation, launch, planetary transfer and installation in the final system. In addition, storage may be required during any phase of operations. Each of these phases requires the payload to be lifted and secured to a vehicle, transported, released and lifted in preparation for the next transportation or storage phase. A critical component of a successful payload handling approach is a latch and associated carrier system. The latch and carrier system should minimize requirements on the: payload, carrier support structure and payload handling devices as well as be able to accommodate a wide range of payload sizes. In addition, the latch should; be small and lightweight, support a method to apply preload, be reusable, integrate into a minimal set of hard-points and have manual interfaces to actuate the latch should a problem occur. A latching system which meets these requirements has been

  14. Water in the Solar System: The Development of Science Education Curriculum Focused on Planetary Exploration

    Science.gov (United States)

    Edgar, L. A.; Anderson, R. B.; Gaither, T. A.; Milazzo, M. P.; Vaughan, R. G.; Rubino-Hare, L.; Clark, J.; Ryan, S.

    2017-12-01

    "Water in the Solar System" is an out-of-school time (OST) science education activity for middle school students that was developed as part of the Planetary Learning that Advances the Nexus of Engineering, Technology, and Science (PLANETS) project. The PLANETS project was selected in support of the NASA Science Mission Directorate's Science Education Cooperative Agreement Notice, with the goal of developing and disseminating OST curriculum and related professional development modules that integrate planetary science, technology, and engineering. "Water in the Solar System" is a science activity that addresses the abundance and availability of water in the solar system. The activity consists of three exercises based on the following guiding questions: 1) How much water is there on the Earth? 2) Where can you find water in the solar system? and 3) What properties affect whether or not water can be used by astronauts? The three exercises involve a scaling relationship demonstration about the abundance of useable water on Earth, a card game to explore where water is found in the solar system, and a hands-on exercise to investigate pH and salinity. Through these activities students learn that although there is a lot of water on Earth, most of it is not in a form that is accessible for humans to use. They also learn that most water in the solar system is actually farther from the sun, and that properties such as salinity and pH affect whether water can be used by humans. In addition to content for students, the activity includes background information for educators, and links to in-depth descriptions of the science content. "Water in the Solar System" was developed through collaboration between subject matter experts at the USGS Astrogeology Science Center, and curriculum and professional development experts in the Center for Science Teaching and Learning at Northern Arizona University. Here we describe our process of curriculum development, education objectives of

  15. Geophysical Investigations of Hypersaline Subglacial Water Systems in the Canadian Arctic: A Planetary Analog

    Science.gov (United States)

    Rutishauser, A.; Sharp, M. J.; Blankenship, D. D.; Skidmore, M. L.; Grima, C.; Schroeder, D. M.; Greenbaum, J. S.; Dowdeswell, J. A.; Young, D. A.

    2017-12-01

    Robotic exploration and remote sensing of the solar system have identified the presence of liquid water beneath ice on several planetary bodies, with evidence for elevated salinity in certain cases. Subglacial water systems beneath Earth's glaciers and ice sheets may provide terrestrial analogs for microbial habitats in such extreme environments, especially those with higher salinity. Geological data suggest that several ice caps and glaciers in the eastern Canadian High Arctic are partially underlain by evaporite-rich sedimentary rocks, and subglacial weathering of these rocks is potentially conducive to the formation of hypersaline subglacial waters. Here, we combine airborne geophysical data with geological constraints to identify and characterize hypersaline subglacial water systems beneath ice caps in Canada's Queen Elizabeth Islands. High relative bedrock reflectivity and specularity anomalies that are apparent in radio-echo sounding data indicate multiple locations where subglacial water is present in areas where modeled ice temperatures at the glacier bed are well below the pressure melting point. This suggests that these water systems are hypersaline, with solute concentrations that significantly depress the freezing point of water. From combined interpretations of geological and airborne-magnetic data, we define the geological context within which these systems have developed, and identify possible solute-sources for the inferred brine-rich water systems. We also derive subglacial hydraulic potential gradients using airborne laser altimetry and ice thickness data, and apply water routing models to derive subglacial drainage pathways. These allow us to identify marine-terminating glaciers where outflow of the brine-rich waters may be anticipated. These hypersaline subglacial water systems beneath Canadian Arctic ice caps and glaciers may represent robust microbial habitats, and potential analogs for brines that may exist beneath ice masses on planetary

  16. THE HYADES CLUSTER: IDENTIFICATION OF A PLANETARY SYSTEM AND ESCAPING WHITE DWARFS

    International Nuclear Information System (INIS)

    Zuckerman, B.; Xu, S.; Klein, B.; Jura, M.

    2013-01-01

    Recently, some hot DA-type white dwarfs have been proposed to plausibly be escaping members of the Hyades. We used hydrogen Balmer lines to measure the radial velocities of seven such stars and confirm that three, and perhaps two others, are/were indeed cluster members and one is not. The other candidate Hyad is strongly magnetic and its membership status remains uncertain. The photospheres of at least one quarter of field white dwarf stars are ''polluted'' by elements heavier than helium that have been accreted. These stars are orbited by extended planetary systems that contain both debris belts and major planets. We surveyed the seven classical single Hyades white dwarfs and the newly identified (escaping) Hyades white dwarfs and found calcium in the photosphere of LP 475-242 of type DBA (now DBAZ), thus implying the presence of an orbiting planetary system. The spectrum of white dwarf GD 31, which may be, but probably is not, an escaping member of the Hyades, displays calcium absorption lines; these originate either from the interstellar medium or, less likely, from a gaseous circumstellar disk. If GD 31 was once a Hyades member, then it would be the first identified white dwarf Hyad with a cooling age >340 Myr.

  17. M-BAND IMAGING OF THE HR 8799 PLANETARY SYSTEM USING AN INNOVATIVE LOCI-BASED BACKGROUND SUBTRACTION TECHNIQUE

    International Nuclear Information System (INIS)

    Galicher, Raphael; Marois, Christian; Macintosh, Bruce; Konopacky, Quinn; Barman, Travis

    2011-01-01

    Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5 Gyr old solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of three of the four currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is three times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of nine. These M-band detections extend the broadband photometric coverage out to ∼5 μm and provide access to the strong CO fundamental absorption band at 4.5 μm. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty, and non-equilibrium CO/CH 4 chemistry models.

  18. Transitivity and ergodicity of quantum systems

    International Nuclear Information System (INIS)

    Narnhofer, H.; Thirring, W.; Wiklicky, H.

    1987-01-01

    First we try to generalize the notion of a topological transitive or a topologically mixing system for quantum mechanical systems in a consistent way. Furthermore we compare these ergodic properties with the classical results. Finaly we deal with some aspects of nearly abelian systems and investigate some relations between these notions. 11 refs. (Author)

  19. Transition to a hydrogen fuel cell transit bus fleet for Canadian urban transit system

    International Nuclear Information System (INIS)

    Ducharme, P.

    2004-01-01

    'Full text:' The Canadian Transportation Fuel Cell Alliance (CTFCA), created by the Canadian Government as part of its 2000 Climate Change Action Plan, has commissioned MARCON-DDM's Hydrogen Intervention Team (HIT) to provide a roadmap for urban transit systems that wish to move to hydrogen fuel cell-powered bus fleets. HIT is currently in the process of gathering information from hydrogen technology providers, bus manufacturers, fuelling system providers and urban transit systems in Canada, the US and Europe. In September, HIT will be in a position to provide a preview of its report to the CTFCA, due for October 2004. The planned table of contents includes: TOMORROW'S FUEL CELL (FC) URBAN TRANSIT BUS - Powertrain, on-board fuel technologies - FC engine system manufacturers - Bus technical specifications, performances, operating characteristics - FC bus manufacturers TOMORROW'S FC TRANSIT PROPERTY - Added maintenance, facilities and fuelling infrastructure requirements - Supply chain implications - Environmental and safety issues - Alternative operational concepts PATHWAYS TO THE FUTURE - Choosing the future operational concept - 'Gap' assessment - how long from here to there? - Facilities and fleet adjustments, including fuelling infrastructure - Risk mitigation, code compliance measures TRANSITIONAL CONSIDERATIONS - Cost implications - Transition schedule (author)

  20. MODELING PLANETARY SYSTEM FORMATION WITH N-BODY SIMULATIONS: ROLE OF GAS DISK AND STATISTICS COMPARED TO OBSERVATIONS

    International Nuclear Information System (INIS)

    Liu Huigen; Zhou Jilin; Wang Su

    2011-01-01

    During the late stage of planet formation, when Mars-sized cores appear, interactions among planetary cores can excite their orbital eccentricities, accelerate their merging, and thus sculpt their final orbital architecture. This study contributes to the final assembling of planetary systems with N-body simulations, including the type I or II migration of planets and gas accretion of massive cores in a viscous disk. Statistics on the final distributions of planetary masses, semimajor axes, and eccentricities are derived and are comparable to those of the observed systems. Our simulations predict some new orbital signatures of planetary systems around solar mass stars: 36% of the surviving planets are giant planets (>10 M + ). Most of the massive giant planets (>30 M + ) are located at 1-10 AU. Terrestrial planets are distributed more or less evenly at J in highly eccentric orbits (e > 0.3-0.4). The average eccentricity (∼0.15) of the giant planets (>10 M + ) is greater than that (∼0.05) of the terrestrial planets ( + ). A planetary system with more planets tends to have smaller planet masses and orbital eccentricities on average.

  1. Planetary geology

    CERN Document Server

    Gasselt, Stephan

    2018-01-01

    This book provides an up-to-date interdisciplinary geoscience-focused overview of solid solar system bodies and their evolution, based on the comparative description of processes acting on them. Planetary research today is a strongly multidisciplinary endeavor with efforts coming from engineering and natural sciences. Key focal areas of study are the solid surfaces found in our Solar System. Some have a direct interaction with the interplanetary medium and others have dynamic atmospheres. In any of those cases, the geological records of those surfaces (and sub-surfaces) are key to understanding the Solar System as a whole: its evolution and the planetary perspective of our own planet. This book has a modular structure and is divided into 4 sections comprising 15 chapters in total. Each section builds upon the previous one but is also self-standing. The sections are:  Methods and tools Processes and Sources  Integration and Geological Syntheses Frontiers The latter covers the far-reaching broad topics of exo...

  2. A detailed analysis of the HD 73526 2:1 resonant planetary system

    Energy Technology Data Exchange (ETDEWEB)

    Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G.; Salter, G. S.; Bailey, J.; Wright, D. [School of Physics, University of New South Wales, Sydney 2052 (Australia); Tan, Xianyu; Lee, Man Hoi [Department of Earth Sciences, The University of Hong Kong, Pokfulam Road (Hong Kong); Butler, R. P.; Arriagada, P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Carter, B. D. [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Jones, H. R. A. [University of Hertfordshire, Centre for Astrophysics Research, Science and Technology Research Institute, College Lane, AL10 9AB, Hatfield (United Kingdom); O' Toole, S. J. [Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670 (Australia); Crane, J. D.; Schectman, S. A.; Thompson, I. [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Minniti, D.; Diaz, M., E-mail: rob@phys.unsw.edu.au [Institute of Astrophysics, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

    2014-01-10

    We present six years of new radial velocity data from the Anglo-Australian and Magellan Telescopes on the HD 73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical (interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40° and 60°, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is no clearly preferred system inclination, the dynamical fit with i = 90° provides the best combination of goodness-of-fit and long-term dynamical stability.

  3. A Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing (SAPE)

    Science.gov (United States)

    Samareh, Jamshid A.

    2009-01-01

    SAPE is a Python-based multidisciplinary analysis tool for systems analysis of planetary entry, descent, and landing (EDL) for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. The purpose of SAPE is to provide a variable-fidelity capability for conceptual and preliminary analysis within the same framework. SAPE includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and structural sizing. SAPE uses the Python language-a platform-independent open-source software for integration and for the user interface. The development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE runs on Microsoft Windows and Apple Mac OS X and has been partially tested on Linux.

  4. Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates

    Energy Technology Data Exchange (ETDEWEB)

    Fabrycky, Daniel C.; Lissauer, Jack J.; Ragozzine, Darin; Rowe, Jason F.; Steffen, Jason H.; Agol, Eric; Barclay, Thomas; Batalha, Natalie; Borucki, William; Ciardi, David R.; Ford, Eric B.; Gautier, Thomas N.; Geary, John C.; Holman, Matthew J.; Jenkins, Jon M.; Li, Jie; Morehead, Robert C.; Morris, Robert L.; Shporer, Avi; Smith, Jeffrey C.; Still, Martin; Van Cleve, Jeffrey

    2014-07-16

    Having discovered 885 planet candidates in 361 multiple-planet systems, Kepler has made transits a powerful method for studying the statistics of planetary systems. The orbits of only two pairs of planets in these candidate systems are apparently unstable. This indicates that a high percentage of the candidate systems are truly planets orbiting the same star, motivating physical investigations of the population. Pairs of planets in this sample are typically not in orbital resonances. However, pairs with orbital period ratios within a few percent of a first-order resonance (e.g. 2:1, 3:2) prefer orbital spacings just wide of the resonance and avoid spacings just narrow of the resonance. Finally, we investigate mutual inclinations based on transit duration ratios. We infer that the inner planets of pairs tend to have a smaller impact parameter than their outer companions, suggesting these planetary systems are typically coplanar to within a few degrees.

  5. Studying Tidal Effects In Planetary Systems With Posidonius. A N-Body Simulator Written In Rust.

    Science.gov (United States)

    Blanco-Cuaresma, Sergi; Bolmont, Emeline

    2017-10-01

    Planetary systems with several planets in compact orbital configurations such as TRAPPIST-1 are surely affected by tidal effects. Its study provides us with important insight about its evolution. We developed a second generation of a N-body code based on the tidal model used in Mercury-T, re-implementing and improving its functionalities using Rust as programming language (including a Python interface for easy use) and the WHFAST integrator. The new open source code ensures memory safety, reproducibility of numerical N-body experiments, it improves the spin integration compared to Mercury-T and allows to take into account a new prescription for the dissipation of tidal inertial waves in the convective envelope of stars. Posidonius is also suitable for binary system simulations with evolving stars.

  6. Spitzer MIPS Limits on Asteroidal Dust in the Pulsar Planetary System PSR B1257+12

    Science.gov (United States)

    Bryden, G.; Beichman, C. A.; Rieke, G. H.; Stansberry, J. A.; Stapelfeldt, K. R.; Trilling, D. E.; Turner, N. J.; Wolszczan, A.

    2006-01-01

    With the MIPS camera on Spitzer, we have searched for far-infrared emission from dust in the planetary system orbiting pulsar PSR B1257+12. With accuracies of 0.05 mJy at 24 microns and 1.5 mJy at 70 microns, photometric measurements find no evidence for emission at these wavelengths. These observations place new upper limits on the luminosity of dust with temperatures between 20 and 1000 K. They are particularly sensitive to dust temperatures of 100-200 K, for which they limit the dust luminosity to below 3 x 10(exp -5) of the pulsar's spin-down luminosity, 3 orders of magnitude better than previous limits. Despite these improved constraints on dust emission, an asteroid belt similar to the solar system's cannot be ruled out.

  7. Refinement Checking on Parametric Modal Transition Systems

    DEFF Research Database (Denmark)

    Benes, Nikola; Kretínsky, Jan; Larsen, Kim Guldstrand

    2015-01-01

    Modal transition systems (MTS) is a well-studied specification formalism of reactive systems supporting a step-wise refinement methodology. Despite its many advantages, the formalism as well as its currently known extensions are incapable of expressing some practically needed aspects in the refin...

  8. Verifying duration properties of timed transition systems

    DEFF Research Database (Denmark)

    Liu, Zhiming; Ravn, Anders P.; Li, Xiaoshan

    1998-01-01

    This paper proposes a method for formal real-time systems development:Requirements and high level design decisions are time interval properties and are therefore specified in the Duration Calculus (DC), while implementations are described bytimed transition systems (TTS). A link from implementati...

  9. Evaluating the biological potential in samples returned from planetary satellites and small solar system bodies: framework for decision making

    National Research Council Canada - National Science Library

    National Research Council Staff; Space Studies Board; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    ... from Planetary Satellites and Small Solar System Bodies Framework for Decision Making Task Group on Sample Return from Small Solar System Bodies Space Studies Board Commission on Physical Sciences, Mathematics, and Applications National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1998 i Copyrightthe true use are Please breaks...

  10. Dynamical Stability of Imaged Planetary Systems in Formation: Application to HL Tau

    Science.gov (United States)

    Tamayo, D.; Triaud, A. H. M. J.; Menou, K.; Rein, H.

    2015-06-01

    A recent Atacama Large Millimeter/Submillimeter Array image revealed several concentric gaps in the protoplanetary disk surrounding the young star HL Tau. We consider the hypothesis that these gaps are carved by planets, and present a general framework for understanding the dynamical stability of such systems over typical disk lifetimes, providing estimates for the maximum planetary masses. We collect these easily evaluated constraints into a workflow that can help guide the design and interpretation of new observational campaigns and numerical simulations of gap opening in such systems. We argue that the locations of resonances should be significantly shifted in massive disks like HL Tau, and that theoretical uncertainties in the exact offset, together with observational errors, imply a large uncertainty in the dynamical state and stability in such disks. This presents an important barrier to using systems like HL Tau as a proxy for the initial conditions following planet formation. An important observational avenue to breaking this degeneracy is to search for eccentric gaps, which could implicate resonantly interacting planets. Unfortunately, massive disks like HL Tau should induce swift pericenter precession that would smear out any such eccentric features of planetary origin. This motivates pushing toward more typical, less massive disks. For a nominal non-resonant model of the HL Tau system with five planets, we find a maximum mass for the outer three bodies of approximately 2 Neptune masses. In a resonant configuration, these planets can reach at least the mass of Saturn. The inner two planets’ masses are unconstrained by dynamical stability arguments.

  11. Education Systems as Transition Spaces

    Science.gov (United States)

    Tikkanen, Jenni; Bledowski, Piotr; Felczak, Joanna

    2015-01-01

    The changes that have occurred in the field of education over the course of the last couple of decades have been associated with increased demands that are not only placed on individuals from both within and beyond the education system, but also on the support they require to make successful educational choices. One central way this need is being…

  12. Isothermal transitions of a thermosetting system

    Science.gov (United States)

    Gillham, J. K.; Benci, J. A.; Noshay, A.

    1974-01-01

    A study of the curing reactions of a cycloaliphatic epoxy resin/anhydride system by torsional braid analysis showed the existence of two critical isothermal temperatures - namely, the maximum glass transition temperature of the thermoset system and the glass transition temperature of the material at its gel point. Two rheologically active kinetic transitions occur during isothermal cure which correspond to gelation and vitrification. Three types of isothermal behavior occur. Methods for determining the time to gel and the time to vitrify, and also the two above-mentioned critical isothermal temperatures, have been developed. The time to gel obeyed the Arrhenius relationship, whereas the time to vitrify passed through a minimum. Application of these results to thermosetting systems in general is discussed in terms of the influence of molecular structure on the values of the critical isothermal temperatures.

  13. Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models

    Energy Technology Data Exchange (ETDEWEB)

    Fabrycky, Daniel C.; /UC, Santa Cruz; Ford, Eric B.; /Florida U.; Steffen, Jason H.; /Fermilab; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Moorhead, Althea V.; /Florida U.; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Bryson, Steve; /NASA, Ames; Buchhave, Lars A.; /Bohr Inst. /Copenhagen U.; Christiansen, Jessie L.; /SETI Inst., Mtn. View /NASA, Ames /Caltech

    2012-01-01

    Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems architectures, even in cases for which high-precision Doppler follow-up is impractical.

  14. Exploring the Largest Mass Fraction of the Solar System: the Case for Planetary Interiors

    Science.gov (United States)

    Danielson, L. R.; Draper, D.; Righter, K.; McCubbin, F.; Boyce, J.

    2017-01-01

    Why explore planetary interiors: The typical image that comes to mind for planetary science is that of a planet surface. And while surface data drive our exploration of evolved geologic processes, it is the interiors of planets that hold the key to planetary origins via accretionary and early differentiation processes. It is that initial setting of the bulk planet composition that sets the stage for all geologic processes that follow. But nearly all of the mass of planets is inaccessible to direct examination, making experimentation an absolute necessity for full planetary exploration.

  15. Architecture of Kepler's multi-transiting systems. II. New investigations with twice as many candidates

    International Nuclear Information System (INIS)

    Fabrycky, Daniel C.; Lissauer, Jack J.; Rowe, Jason F.; Barclay, Thomas; Batalha, Natalie; Borucki, William; Jenkins, Jon M.; Li, Jie; Morris, Robert L.; Smith, Jeffrey C.; Ragozzine, Darin; Geary, John C.; Holman, Matthew J.; Steffen, Jason H.; Agol, Eric; Ciardi, David R.; Ford, Eric B.; Morehead, Robert C.; Gautier, Thomas N.; Shporer, Avi

    2014-01-01

    We report on the orbital architectures of Kepler systems having multiple-planet candidates identified in the analysis of data from the first six quarters of Kepler data and reported by Batalha et al. (2013). These data show 899 transiting planet candidates in 365 multiple-planet systems and provide a powerful means to study the statistical properties of planetary systems. Using a generic mass-radius relationship, we find that only two pairs of planets in these candidate systems (out of 761 pairs total) appear to be on Hill-unstable orbits, indicating ∼96% of the candidate planetary systems are correctly interpreted as true systems. We find that planet pairs show little statistical preference to be near mean-motion resonances. We identify an asymmetry in the distribution of period ratios near first-order resonances (e.g., 2:1, 3:2), with an excess of planet pairs lying wide of resonance and relatively few lying narrow of resonance. Finally, based upon the transit duration ratios of adjacent planets in each system, we find that the interior planet tends to have a smaller transit impact parameter than the exterior planet does. This finding suggests that the mode of the mutual inclinations of planetary orbital planes is in the range 1.°0-2.°2, for the packed systems of small planets probed by these observations.

  16. Architecture of Kepler's multi-transiting systems. II. New investigations with twice as many candidates

    Energy Technology Data Exchange (ETDEWEB)

    Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lissauer, Jack J.; Rowe, Jason F.; Barclay, Thomas; Batalha, Natalie; Borucki, William; Jenkins, Jon M.; Li, Jie; Morris, Robert L.; Smith, Jeffrey C. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Ragozzine, Darin; Geary, John C.; Holman, Matthew J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, MS 127, Batavia, IL 60510 (United States); Agol, Eric [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, 770 South Wilson Avenue, MC 100-2, Pasadena, CA 91125 (United States); Ford, Eric B.; Morehead, Robert C. [Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); Gautier, Thomas N.; Shporer, Avi, E-mail: fabrycky@uchicago.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); and others

    2014-08-01

    We report on the orbital architectures of Kepler systems having multiple-planet candidates identified in the analysis of data from the first six quarters of Kepler data and reported by Batalha et al. (2013). These data show 899 transiting planet candidates in 365 multiple-planet systems and provide a powerful means to study the statistical properties of planetary systems. Using a generic mass-radius relationship, we find that only two pairs of planets in these candidate systems (out of 761 pairs total) appear to be on Hill-unstable orbits, indicating ∼96% of the candidate planetary systems are correctly interpreted as true systems. We find that planet pairs show little statistical preference to be near mean-motion resonances. We identify an asymmetry in the distribution of period ratios near first-order resonances (e.g., 2:1, 3:2), with an excess of planet pairs lying wide of resonance and relatively few lying narrow of resonance. Finally, based upon the transit duration ratios of adjacent planets in each system, we find that the interior planet tends to have a smaller transit impact parameter than the exterior planet does. This finding suggests that the mode of the mutual inclinations of planetary orbital planes is in the range 1.°0-2.°2, for the packed systems of small planets probed by these observations.

  17. Transit Duration Variations due to Secular Interactions in Systems with Tightly-packed Inner Planets

    Science.gov (United States)

    Boley, Aaron; Van Laerhoven, Christa; Granados Contreras, A. Paula

    2018-04-01

    Secular interactions among planets in multi-planet systems will lead to variations in orbital inclinations and to the precession of orbital nodes. Taking known system architectures at face value, we calculate orbital precession rates for planets in tightly-packed systems using classical second-order secular theory, in which the orientation of the orbits can be described as a vector sum of eigenmodes and the eigenstructure is determined only by the masses and semi-major axes of the planets. Using this framework, we identify systems that have fast precession frequencies, and use those systems to explore the range of transit duration variation that could occur using amplitudes that are consistent with tightly-packed planetary systems. We then further assess how transit duration variations could be used in practice.

  18. Simulations of phase transitions in ionic systems

    International Nuclear Information System (INIS)

    Panagiotopoulos, A Z

    2005-01-01

    A review of recent simulation work in the area of phase transitions in ionic systems is presented. The vapour-liquid transition for the restricted primitive model has been studied extensively in the past decade. The critical temperature is now known to excellent accuracy and the critical density to moderate accuracy. There is also strong simulation-based evidence that the model is in the Ising universality class. Discretized lattice versions of the model are reviewed. Other systems covered are size- and charge-asymmetric electrolytes, colloid-salt mixtures, realistic salt models and charged chains. Areas of future research needs are briefly discussed

  19. Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems

    Science.gov (United States)

    Clark, Roger N.; Swayze, Gregg A.; Livo, K. Eric; Kokaly, Raymond F.; Sutley, Steve J.; Dalton, J. Brad; McDougal, Robert R.; Gent, Carol A.

    2003-01-01

    millions of dollars and years in cleanup time. Imaging spectroscopy data and Tetracorder analysis can be used to study both terrestrial and planetary science problems. Imaging spectroscopy can be used to probe planetary systems, including their atmospheres, oceans, and land surfaces.

  20. BPI Challenge 2012 : the transition system case

    NARCIS (Netherlands)

    Verbeek, H.M.W.; La Rosa, M.; Soffer, P.

    2013-01-01

    Using the Transition System Miner as available in ProM6, we have investigated the control-flow perspective, the data perspective, and the resource perspective of the process that underlies the event log provided for the BPI Challenge 2012.

  1. Phase transition signals of finite systems

    International Nuclear Information System (INIS)

    Duflot-Flandrois, Veronique

    2001-01-01

    Phase transitions are universal properties of interacting matter. They are well described if the considered system is infinite, by using standard thermodynamics. But in the case of small systems like atomic nuclei, this formalism cannot be applied anymore. Our aim is to propose a statistical mechanics approach in order to define the thermodynamical features of small open systems subject to non-saturating forces. We concentrate in particular on the definition and characterization for such systems of phase transitions belonging to the liquid gas universality class. Theoretical and experimental observables are defined to signal the occurrence and the order of this transition without any ambiguity. One of the most relevant and experimentally accessible observables consists in the study of kinetic energy fluctuations for a fixed value of the total deposited energy. In a first order phase transition such fluctuations become anomaly high and at the same time the size distribution appears to behave critically. All our results are obtained within numerical simulations of the lattice gas model with a nearest neighbors attractive interaction. Finally we check the influence of non-saturating forces, developing the specific example of the Coulomb interaction in the nucleus. Future improvements and perspectives at this work consist in the analysis of specific effects occurring in nuclei: isospin and quantum mechanics. (author) [fr

  2. REFINED SYSTEM PARAMETERS AND TTV STUDY OF TRANSITING EXOPLANETARY SYSTEM HAT-P-20

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Leilei; Gu, Shenghong; Wang, Xiaobin; Cao, Dongtao; Wang, Yibo; Xiang, Yue [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Cameron, Andrew Collier [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Hui, Ho-Keung; Kwok, Chi-Tai [Ho Koon Nature Education cum Astronomical Centre, Sik Sik Yuen, Hong Kong (China); Yeung, Bill; Ng, Eric [Hong Kong Astronomical Society, Hong Kong (China); Horta, Ferran Grau, E-mail: wangxb@ynao.ac.cn [Observatori Ca l’Ou, C/de Dalt 18, Sant Martí Sesgueioles (Spain)

    2017-01-01

    We report new photometric observations of the transiting exoplanetary system HAT-P-20, obtained using CCD cameras at Yunnan Observatories and Ho Koon Nature Education cum Astronomical Centre, China, from 2010 to 2013, and Observatori Ca l’Ou, Sant Marti Sesgueioles, Spain, from 2013 to 2015. The observed data are corrected for systematic errors according to the coarse de-correlation and SYSREM algorithms, so as to enhance the signal of the transit events. In order to consistently model the star spots and transits of this exoplanetary system, we develop a highly efficient tool STMT based on the analytic models of Mandel and Agol and Montalto et al. The physical parameters of HAT-P-20 are refined by homogeneously analyzing our new data, the radial velocity data, and the earlier photometric data in the literature with the Markov chain Monte Carlo technique. New radii and masses of both host star and planet are larger than those in the discovery paper due to the discrepancy of the radius among K-dwarfs between predicted values by standard stellar models and empirical calibration from observations. Through the analysis of all available mid-transit times calculated with the normal model and spotted model, we conclude that the periodic transit timing variations in these transit events revealed by employing the normal model are probably induced by spot crossing events. From the analysis of the distribution of occulted spots by HAT-P-20b, we constrain the misaligned architecture between the planetary orbit and the spin of the host star.

  3. Gifts from Exoplanetary Transits

    Science.gov (United States)

    Narita, Norio

    2009-08-01

    The discovery of transiting extrasolar planets has enabled us to do a number of interesting studies. Transit photometry reveals the radius and the orbital inclination of transiting planets, which allows us to learn the true mass and density of the respective planets by the combined information from radial velocity (RV) measurements. In addition, follow-up observations of transiting planets, looking at such things as secondary eclipses, transit timing variations, transmission spectroscopy, and the Rossiter-McLaughlin effect, provide us information about their dayside temperatures, unseen bodies in systems, planetary atmospheres, and the obliquity of planetary orbits. Such observational information, which will provide us a greater understanding of extrasolar planets, is available only for transiting planets. Here, I briefly summarize what we can learn from transiting planets and introduce previous studies.

  4. Managing innovation systems in transition economies

    OpenAIRE

    Baković, Tomislav

    2010-01-01

    Successfully managing innovations has become the basic precondition for the development of both companies and national economies. At the national level governments are forming innovation systems whose primary goal is to create conditions at which science and technology can flourish and then transfer their findings trough private sector into new revolutionary products and services. Unfortunately not all countries have the same preconditions for creating such systems and transition economies du...

  5. Phase transitions in two-dimensional systems

    International Nuclear Information System (INIS)

    Salinas, S.R.A.

    1983-01-01

    Some experiences are related using synchrotron radiation beams, to characterize solid-liquid (fusion) and commensurate solid-uncommensurate solid transitions in two-dimensional systems. Some ideas involved in the modern theories of two-dimensional fusion are shortly exposed. The systems treated consist of noble gases (Kr,Ar,Xe) adsorbed in the basal plane of graphite and thin films formed by some liquid crystal shells. (L.C.) [pt

  6. Planetary Rings

    Science.gov (United States)

    Nicholson, P. D.

    2001-11-01

    A revolution in the studies in planetary rings studies occurred in the period 1977--1981, with the serendipitous discovery of the narrow, dark rings of Uranus, the first Voyager images of the tenuous jovian ring system, and the many spectacular images returned during the twin Voyager flybys of Saturn. In subsequent years, ground-based stellar occultations, HST observations, and the Voyager flybys of Uranus (1986) and Neptune (1989), as well as a handful of Galileo images, provided much additional information. Along with the completely unsuspected wealth of detail these observations revealed came an unwelcome problem: are the rings ancient or are we privileged to live at a special time in history? The answer to this still-vexing question may lie in the complex gravitational interactions recent studies have revealed between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto parent bodies. Perhaps most puzzling is Saturn's multi-stranded, clumpy F ring, which continues to defy a simple explanation 20 years after it was first glimpsed in grainy images taken by Pioneer 11. Voyager and HST images reveal a complex, probably chaotic, dynamical interaction between unseen parent bodies within this ring and its two shepherd satellites, Pandora and Prometheus. The work described here reflects contributions by Joe Burns, Jeff Cuzzi, Luke Dones, Dick French, Peter Goldreich, Colleen McGhee, Carolyn Porco, Mark Showalter, and Bruno Sicardy, as well as those of the author. This research has been supported by NASA's Planetary Geology and Geophysics program and the

  7. Planetary magnetospheres

    International Nuclear Information System (INIS)

    Hill, T.W.; Michel, F.C.

    1975-01-01

    Recent planetary probes have resulted in the realization of the generality of magnetospheric interactions between the solar wind and the planets. The three categories of planetary magnetospheres are discussed: intrinsic slowly rotating magnetospheres, intrinsic rapidly rotating magnetospheres, and induced magnetospheres. (BJG)

  8. Dynamical models to explain observations with SPHERE in planetary systems with double debris belts

    Science.gov (United States)

    Lazzoni, C.; Desidera, S.; Marzari, F.; Boccaletti, A.; Langlois, M.; Mesa, D.; Gratton, R.; Kral, Q.; Pawellek, N.; Olofsson, J.; Bonnefoy, M.; Chauvin, G.; Lagrange, A. M.; Vigan, A.; Sissa, E.; Antichi, J.; Avenhaus, H.; Baruffolo, A.; Baudino, J. L.; Bazzon, A.; Beuzit, J. L.; Biller, B.; Bonavita, M.; Brandner, W.; Bruno, P.; Buenzli, E.; Cantalloube, F.; Cascone, E.; Cheetham, A.; Claudi, R. U.; Cudel, M.; Daemgen, S.; De Caprio, V.; Delorme, P.; Fantinel, D.; Farisato, G.; Feldt, M.; Galicher, R.; Ginski, C.; Girard, J.; Giro, E.; Janson, M.; Hagelberg, J.; Henning, T.; Incorvaia, S.; Kasper, M.; Kopytova, T.; LeCoroller, H.; Lessio, L.; Ligi, R.; Maire, A. L.; Ménard, F.; Meyer, M.; Milli, J.; Mouillet, D.; Peretti, S.; Perrot, C.; Rouan, D.; Samland, M.; Salasnich, B.; Salter, G.; Schmidt, T.; Scuderi, S.; Sezestre, E.; Turatto, M.; Udry, S.; Wildi, F.; Zurlo, A.

    2018-03-01

    circular or eccentric orbit. We then consider multi-planetary systems: two and three equal-mass planets on circular orbits and two equal-mass planets on eccentric orbits in a packed configuration. As a final step, we compare each couple of values (Mp, ap), derived from the dynamical analysis of single and multiple planetary models, with the detection limits obtained with SPHERE. Results: For one single planet on a circular orbit we obtain conclusive results that allow us to exclude such a hypothesis since in most cases this configuration requires massive planets which should have been detected by our observations. Unsatisfactory is also the case of one single planet on an eccentric orbit for which we obtained high masses and/or eccentricities which are still at odds with observations. Introducing multi planetary architectures is encouraging because for the case of three packed equal-mass planets on circular orbits we obtain quite low masses for the perturbing planets which would remain undetected by our SPHERE observations. The case of two equal-mass planets on eccentric orbits is also of interest since it suggests the possible presence of planets with masses lower than the detection limits and with moderate eccentricity. Our results show that the apparent lack of planets in gaps between double belts could be explained by the presence of a system of two or more planets possibly of low mass and on eccentric orbits whose sizes are below the present detection limits. Based on observations collected at Paranal Observatory, ESO (Chile) Program ID: 095.C-0298, 096.C-0241, 097.C-0865, and 198.C-0209.

  9. Regolith Derived Heat Shield for Planetary Body Entry and Descent System with In Situ Fabrication

    Science.gov (United States)

    Hogue, Michael D.; Meuller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Rasky, Daniel J.

    2012-01-01

    This NIAC project investigated an innovative approach to provide heat shield protection to spacecraft after launch and prior to each EDL thus potentially realizing significant launch mass savings. Heat shields fabricated in situ can provide a thermal-protection system for spacecraft that routinely enter a planetary atmosphere. By fabricating the heat shield with space resources from materials available on moons and asteroids, it is possible to avoid launching the heat-shield mass from Earth. Regolith has extremely good insulating properties and the silicates it contains can be used in the fabrication and molding of thermal-protection materials. Such in situ developed heat shields have been suggested before by Lewis. Prior research efforts have shown that regolith properties can be compatible with very-high temperature resistance. Our project team is highly experienced in regolith processing and thermal protection systems (TPS). Routine access to space and return from any planetary surface requires dealing with heat loads experienced by the spacecraft during reentry. Our team addresses some of the key issues with the EDL of human-scale missions through a highly innovative investigation of heat shields that can be fabricated in space by using local resources on asteroids and moons. Most space missions are one-way trips, dedicated to placing an asset in space for economical or scientific gain. However, for human missions, a very-reliable heat-shield system is necessary to protect the crew from the intense heat experienced at very high entry velocities of approximately 11 km/s at approximately Mach 33 (Apollo). For a human mission to Mars, the return problem is even more difficult, with predicted velocities of up to 14 km/s, at approximately Mach 42 at the Earth-atmosphere entry. In addition to human return, it is very likely that future space-travel architecture will include returning cargo to the Earth, either for scientific purposes or for commercial reasons

  10. An obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation

    Science.gov (United States)

    Liu, L.; Jia, J.; Li, L.

    In this paper we present an implementation of an obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation The fisheye lenses can improve image acquisition efficiency and handle minimal clearance recovery problem because they provide a large field of view However the fisheye lens introduces significant distortion in the image and this will make it much more difficult to find a one-to-one correspondence In addition we have to improve the system accuracy and efficiency for robot navigation To compute dense depth maps accurately in real time the following five key issues are considered 1 using lookup tables for a tradeoff between time and space in fisheye distortion correction and correspondence matching 2 using an improved incremental calculation scheme for algorithmic optimization 3 multimedia instruction set MMX implementation 4 consistency check to remove wrong stereo matching problems suffering from occlusions or mismatches 5 constraints of the recovery space To realize obstacle detection robustly we use the following three steps 1 extracting the ground plane parameters using Randomized Hough Transform 2 filtering the ground and background 3 locating the obstacles by using connected region detection Experimental results show the system can run at 3 2fps in 2 0GHz PC with 640X480 pixels

  11. STABILITY OF ADDITIONAL PLANETS IN AND AROUND THE HABITABLE ZONE OF THE HD 47186 PLANETARY SYSTEM

    International Nuclear Information System (INIS)

    Kopparapu, Ravi Kumar; Raymond, Sean N.; Barnes, Rory

    2009-01-01

    We study the dynamical stability of an additional, potentially habitable planet in the HD 47186 planetary system. Two planets are currently known in this system: a 'hot Neptune' with a period of 4.08 days and a Saturn-mass planet with a period of 3.7 years. Here we consider the possibility that one or more undetected planets exist between the two known planets and possibly within the habitable zone (HZ) in this system. Given the relatively low masses of the known planets, additional planets could have masses ∼ + , and hence be terrestrial-like and further improving potential habitability. We perform N-body simulations to identify the stable zone between planets b and c and find that much of the inner HZ can harbor a 10 M + planet. With the current radial velocity threshold of ∼1 m s -1 , an additional planet should be detectable if it lies at the inner edge of the habitable zone at 0.8 AU. We also show that the stable zone could contain two additional planets of 10 M + each if their eccentricities are lower than ∼0.3.

  12. Mass outflow in the nearby proto-planetary system, Beta Pictoris

    International Nuclear Information System (INIS)

    Bruhweiler, F.C.; Grady, C.A.; Kondo, Yoji

    1991-01-01

    Previous spectral studies of circumstallar dust around the nearby, candidate proto-planetary system, Beta Pictoris, has detected only infalling gas. The lack of detectable mass outflow has been critical in the interpretation of the origin of the circumstellar gas and in our understanding of the evolutionary status of the Beta Pictoris system. IUE high-dispersion spectra are presented which show, in addition to infall, the presence of mass outflow, with a maximum observed outflow velocity of -60 km/s, and a corresponding instantaneous outflow rate of 1.1 x 10 to the -14th solar mass/yr, or 1.1 x 10 to the -11th Jupiter mass/yr. This mass outflow rate and terminal velocity are comparable to the magnitudes of mass infall rates and terminal velocities observed from late 1986 through early 1988. The implications of these observations on our understanding of the mechanisms producing infall from the surrounding circumstellar disk are discussed, as are the implications for our understanding of the evolutionary status of the Beta Pic system. 23 refs

  13. The Planetary Data System - A Case Study in the Development and Management of Meta-Data for a Scientific Digital Library

    Science.gov (United States)

    Hughes, J.

    1998-01-01

    The Planetary Data System (PDS) is an active science data archive managed by scientists for NASA's planetary science community. With the advent of the World Wide Web the majority of the archive has been placed on-line as a science digital libraty for access by scientists, the educational community, and the general public.

  14. The distribution of mass in the planetary system and solar nebulae

    International Nuclear Information System (INIS)

    Weidenschilling, S.J.

    1977-01-01

    A model 'solar nebula' is constructed by adding the solar complement of light elements to each planet, using recent models of planetary compositions. Uncertainties in this approach are estimated. The computed surface density varies approximately as rsup(-3/2). Mercury, Mars and the asteroid belt are anomalously low in mass, but processes exist which would preferentially remove matter from these regions. Planetary masses and compositions are generally consistent with a monotonic density distribution in the primordial solar nebula. (Auth.)

  15. CLOSE STELLAR ENCOUNTERS IN YOUNG, SUBSTRUCTURED, DISSOLVING STAR CLUSTERS: STATISTICS AND EFFECTS ON PLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Craig, Jonathan; Krumholz, Mark R.

    2013-01-01

    Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early evolution in these substructured environments, stars can undergo close encounters with one another that might have significant impacts on their protoplanetary disks or young planetary systems. We perform N-body simulations of the early evolution of dissolving, substructured clusters with a wide range of properties, with the aim of quantifying the expected number and orbital element distributions of encounters as a function of cluster properties. We show that the presence of substructure both boosts the encounter rate and modifies the distribution of encounter velocities compared to what would be expected for a dynamically relaxed cluster. However, the boost only lasts for a dynamical time, and as a result the overall number of encounters expected remains low enough that gravitational stripping is unlikely to be a significant effect for the vast majority of star-forming environments in the Galaxy. We briefly discuss the implications of this result for models of the origin of the solar system, and of free-floating planets. We also provide tabulated encounter rates and orbital element distributions suitable for inclusion in population synthesis models of planet formation in a clustered environment.

  16. CLOSE STELLAR ENCOUNTERS IN YOUNG, SUBSTRUCTURED, DISSOLVING STAR CLUSTERS: STATISTICS AND EFFECTS ON PLANETARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Jonathan; Krumholz, Mark R., E-mail: krumholz@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2013-06-01

    Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early evolution in these substructured environments, stars can undergo close encounters with one another that might have significant impacts on their protoplanetary disks or young planetary systems. We perform N-body simulations of the early evolution of dissolving, substructured clusters with a wide range of properties, with the aim of quantifying the expected number and orbital element distributions of encounters as a function of cluster properties. We show that the presence of substructure both boosts the encounter rate and modifies the distribution of encounter velocities compared to what would be expected for a dynamically relaxed cluster. However, the boost only lasts for a dynamical time, and as a result the overall number of encounters expected remains low enough that gravitational stripping is unlikely to be a significant effect for the vast majority of star-forming environments in the Galaxy. We briefly discuss the implications of this result for models of the origin of the solar system, and of free-floating planets. We also provide tabulated encounter rates and orbital element distributions suitable for inclusion in population synthesis models of planet formation in a clustered environment.

  17. Close Stellar Encounters in Young, Substructured, Dissolving Star Clusters: Statistics and Effects on Planetary Systems

    Science.gov (United States)

    Craig, Jonathan; Krumholz, Mark R.

    2013-06-01

    Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early evolution in these substructured environments, stars can undergo close encounters with one another that might have significant impacts on their protoplanetary disks or young planetary systems. We perform N-body simulations of the early evolution of dissolving, substructured clusters with a wide range of properties, with the aim of quantifying the expected number and orbital element distributions of encounters as a function of cluster properties. We show that the presence of substructure both boosts the encounter rate and modifies the distribution of encounter velocities compared to what would be expected for a dynamically relaxed cluster. However, the boost only lasts for a dynamical time, and as a result the overall number of encounters expected remains low enough that gravitational stripping is unlikely to be a significant effect for the vast majority of star-forming environments in the Galaxy. We briefly discuss the implications of this result for models of the origin of the solar system, and of free-floating planets. We also provide tabulated encounter rates and orbital element distributions suitable for inclusion in population synthesis models of planet formation in a clustered environment.

  18. Planetary Protection: X-ray Super-Flares Aid Formation of "Solar Systems"

    Science.gov (United States)

    2005-05-01

    New results from NASA's Chandra X-ray Observatory imply that X-ray super-flares torched the young Solar System. Such flares likely affected the planet-forming disk around the early Sun, and may have enhanced the survival chances of Earth. By focusing on the Orion Nebula almost continuously for 13 days, a team of scientists used Chandra to obtain the deepest X-ray observation ever taken of this or any star cluster. The Orion Nebula is the nearest rich stellar nursery, located just 1,500 light years away. These data provide an unparalleled view of 1400 young stars, 30 of which are prototypes of the early Sun. The scientists discovered that these young suns erupt in enormous flares that dwarf - in energy, size, and frequency -- anything seen from the Sun today. Illustration of Large Flares Illustration of Large Flares "We don't have a time machine to see how the young Sun behaved, but the next best thing is to observe Sun-like stars in Orion," said Scott Wolk of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "We are getting a unique look at stars between one and 10 million years old - a time when planets form." A key result is that the more violent stars produce flares that are a hundred times as energetic as the more docile ones. This difference may specifically affect the fate of planets that are relatively small and rocky, like the Earth. "Big X-ray flares could lead to planetary systems like ours where Earth is a safe distance from the Sun," said Eric Feigelson of Penn State University in University Park, and principal investigator for the international Chandra Orion Ultradeep Project. "Stars with smaller flares, on the other hand, might end up with Earth-like planets plummeting into the star." Animation of X-ray Flares from a Young Sun Animation of X-ray Flares from a "Young Sun" According to recent theoretical work, X-ray flares can create turbulence when they strike planet-forming disks, and this affects the position of rocky planets as they

  19. Transition control system for procedure prompting

    International Nuclear Information System (INIS)

    Colley, R.W.

    1981-11-01

    A system called the Transition Control System (TCS) is being developed at the Hanford Engineering Development Laboratory (HEDL). The purpose of the TCS is to monitor the operational status of a plant's systems and equipment, and provide either operator guidance or direct control. The TCS provides the rule-based information to the operator specific to the plant's current operational status. A schematic of the information flow and control functions of a reactor plant is shown. The basis for the TCS is a methodology called Sequencing Established States (SES). The fundamental precept of this methodology is that all plant states are determined by the operational status of the various plant systems. The operational status of each plant system is determined, in turn, by the operational status of the system's equipment, instrumentation and controllers

  20. Climate change mitigation through livestock system transitions

    Science.gov (United States)

    Havlík, Petr; Valin, Hugo; Herrero, Mario; Obersteiner, Michael; Schmid, Erwin; Rufino, Mariana C.; Mosnier, Aline; Thornton, Philip K.; Böttcher, Hannes; Conant, Richard T.; Frank, Stefan; Fritz, Steffen; Fuss, Sabine; Kraxner, Florian; Notenbaert, An

    2014-01-01

    Livestock are responsible for 12% of anthropogenic greenhouse gas emissions. Sustainable intensification of livestock production systems might become a key climate mitigation technology. However, livestock production systems vary substantially, making the implementation of climate mitigation policies a formidable challenge. Here, we provide results from an economic model using a detailed and high-resolution representation of livestock production systems. We project that by 2030 autonomous transitions toward more efficient systems would decrease emissions by 736 million metric tons of carbon dioxide equivalent per year (MtCO2e⋅y−1), mainly through avoided emissions from the conversion of 162 Mha of natural land. A moderate mitigation policy targeting emissions from both the agricultural and land-use change sectors with a carbon price of US$10 per tCO2e could lead to an abatement of 3,223 MtCO2e⋅y−1. Livestock system transitions would contribute 21% of the total abatement, intra- and interregional relocation of livestock production another 40%, and all other mechanisms would add 39%. A comparable abatement of 3,068 MtCO2e⋅y−1 could be achieved also with a policy targeting only emissions from land-use change. Stringent climate policies might lead to reductions in food availability of up to 200 kcal per capita per day globally. We find that mitigation policies targeting emissions from land-use change are 5 to 10 times more efficient—measured in “total abatement calorie cost”—than policies targeting emissions from livestock only. Thus, fostering transitions toward more productive livestock production systems in combination with climate policies targeting the land-use change appears to be the most efficient lever to deliver desirable climate and food availability outcomes. PMID:24567375

  1. The statistical model of origin and evolution planets of Solar system and planetary satellities

    Science.gov (United States)

    Krot, A.

    There are the theories for exploring Solar system formation in accord Titius-Bode's low: electromagnetic theories (Birkeland (1912), Alfven (1942)), gravitational theories (Schmidt (1944), Woolfson (1964), Safronov (1969), Dole (1970)), nebular theories (Weizsaecker (1943), Kuiper (1949), Nakano (1970)) [1]-[3]. In spite of great number of work aimed to exploring formation of the Solar system, however, the mentioned theories were not able to explain all phenomena. In this connection the statistical theory for a cosmological body forming (so-called the spheroidal body model) has been proposed in [4]-[11]. Within the framework of this theory, bodies have fuzzy outlines and are represented by means of spheroidal forms. In the work [6], which is a continuation of the papers [4], [5], it has been investigated a slowly evolving in time process of a gravitational compression of a spheroidal body close to an unstable equilibrium state. In the papers [7],[8]the equation of motion of particles inside the weakly gravitating spheroidal body modeled by means of an ideal liquid has been obtained. Using Schwarzschild's and Kerr's metrics a consistency of the proposed statistical model with the general relativity has been shown in [12]. The proposed theory proceeds from the conception for forming a spheroidal body as a protoplanet from planetary nebula; it permits to derive the form of distribution functions for an immovable and rotating spheroidal body [4]-[6],[10]-[13] as well as their density masses (gravitational potentials and strengths) and also to find the distribution function of specific angular momentum of the rotating uniformly spheroidal body [13],[14]. Using the specific angular momentum distribution function this work considers a gas- dust protoplanetary cloud as a rotating and gravitating spheroidal body. Because the specific angular momenta are averaged during conglomeration process the specific angular momenta for a planets of Solar system is found. As a result a

  2. Detection and Localization of Tooth Breakage Fault on Wind Turbine Planetary Gear System considering Gear Manufacturing Errors

    Directory of Open Access Journals (Sweden)

    Y. Gui

    2014-01-01

    Full Text Available Sidebands of vibration spectrum are sensitive to the fault degree and have been proved to be useful for tooth fault detection and localization. However, the amplitude and frequency modulation due to manufacturing errors (which are inevitable in actual planetary gear system lead to much more complex sidebands. Thus, in the paper, a lumped parameter model for a typical planetary gear system with various types of errors is established. In the model, the influences of tooth faults on time-varying mesh stiffness and tooth impact force are derived analytically. Numerical methods are then utilized to obtain the response spectra of the system with tooth faults with and without errors. Three system components (including sun, planet, and ring gears with tooth faults are considered in the discussion, respectively. Through detailed comparisons of spectral sidebands, fault characteristic frequencies of the system are acquired. Dynamic experiments on a planetary gear-box test rig are carried out to verify the simulation results and these results are of great significances for the detection and localization of tooth faults in wind turbines.

  3. THE THREE-DIMENSIONAL ARCHITECTURE OF THE υ ANDROMEDAE PLANETARY SYSTEM

    International Nuclear Information System (INIS)

    Deitrick, Russell; Barnes, Rory; Quinn, Thomas R.; Luger, Rodrigo; Antonsen, Adrienne; McArthur, Barbara; Fritz Benedict, G.

    2015-01-01

    The υ Andromedae system is the first exoplanetary system to have the relative inclination of two planets' orbital planes directly measured, and therefore offers our first window into the three-dimensional configurations of planetary systems. We present, for the first time, full three-dimensional, dynamically stable configurations for the three planets of the system consistent with all observational constraints. While the outer two planets, c and d, are inclined by ∼30°, the inner planet's orbital plane has not been detected. We use N-body simulations to search for stable three-planet configurations that are consistent with the combined radial velocity and astrometric solution. We find that only 10 trials out of 1000 are robustly stable on 100 Myr timescales, or ∼8 billion orbits of planet b. Planet b's orbit must lie near the invariable plane of planets c and d, but can be either prograde or retrograde. These solutions predict that b's mass is in the range of 2-9 M Jup and has an inclination angle from the sky plane of less than 25°. Combined with brightness variations in the combined star/planet light curve ( p hase curve ) , our results imply that planet b's radius is ∼1.8 R Jup , relatively large for a planet of its age. However, the eccentricity of b in several of our stable solutions reaches >0.1, generating upward of 10 19 W in the interior of the planet via tidal dissipation, possibly inflating the radius to an amount consistent with phase curve observations

  4. Planetary Magnetism

    Science.gov (United States)

    Connerney, J. E. P.

    2007-01-01

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

  5. Planetary Defense

    Science.gov (United States)

    2016-05-01

    4 Abstract Planetary defense against asteroids should be a major concern for every government in the world . Millions of asteroids and...helps make Planetary Defense viable because defending the Earth against asteroids benefits from all the above technologies. So if our planet security...information about their physical characteristics so we can employ the right strategies. It is a crucial difference if asteroids are made up of metal

  6. Homogeneous Photodynamical Analysis of Kepler's Multiply-Transiting Systems

    Science.gov (United States)

    Ragozzine, Darin

    . Research Objective 1 (RO1) Gather and detrend publicly-available light curves for Kepler MTSs; gather starting guesses of preliminary planetary and stellar parameters from the Kepler pipeline (e.g., Rowe et al. 2014) and other studies; and expand our existing photodynamical code (e.g., Mills & Fabrycky 2017) to handle all Kepler MTSs. All required data are publicly available and our significant past expertise demonstrates our ability to complete these tasks. The new photodynamical code will be called the PhotoDynamical Multi-planet Model (PhoDyMM) and described in a paper. Research Objective 2 (RO2) Apply PhoDyMM to the 600 known systems with 2-3 transiting planets; publish these results, including full posterior distributions for all systems (to be housed at the NASA Exoplanet Archive). Research Objective 3 (RO3) Apply PhoDyMM to the 100 Kepler MTSs with 4 or more planets. This astrophysics data analysis is a major step beyond existing efforts and will provide the definitive physical and orbital properties for Kepler MTSs. It is clearly responsive to the Astrophysics Data Analysis Program and relevant to NASA Astrophysics Goals. PI Ragozzine and Co-I Fabrycky have participated in the Kepler prime science mission since its inception and have significant experience in all required areas. Co-I Mills has the most published uses of a photodynamical model on some of the most difficult to analyze exoplanetary systems (Kepler-11, Kepler-108 Kepler-223, Kepler-444). We will employ best practices for Data Management such as archiving posterior distributions and providing open access to PhoDyMM. PI Ragozzine s startup provided sufficient computational resources to perform the extensive analyses. He will be supported by a graduate student and unfunded undergraduates.

  7. Economic System and Transition Mode : A Comparative Research on Transition Economies

    OpenAIRE

    Yang, Liu

    2014-01-01

    This passage mainly deals with the problem of why different transition countries have different transition mode and different economic performance. According to this research, it has been found that the economic system of the traditional socialist countries played an important role in their process of reform and transition. The socialist countries with their different economic systems had determined the economic performance, the space, as well as the environment of the transition. All of this...

  8. TRANSIT

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. TRANSIT. SYSTEM: DETERMINE 2D-POSITION GLOBALLY BUT INTERMITTENT (POST-FACTO). IMPROVED ACCURACY. PRINCIPLE: POLAR SATELLITES WITH INNOVATIONS OF: GRAVITY-GRADIENT ATTITUDE CONTROL; DRAG COMPENSATION. WORKS ...

  9. A Comparison of the Dynamical Evolution of Planetary Systems Proceedings of the Sixth Alexander von Humboldt Colloquium on Celestial Mechanics Bad Hofgastein (Austria), 21–27 March 2004

    CERN Document Server

    Dvorak, Rudolf

    2005-01-01

    The papers in this volume cover a wide range of subjects covering the most recent developments in Celestial Mechanics from the theoretical point of nonlinear dynamical systems to the application to real problems. We emphasize the papers on the formation of planetary systems, their stability and also the problem of habitable zones in extrasolar planetary systems. A special topic is the stability of Trojans in our planetary system, where more and more realistic dynamical models are used to explain their complex motions: besides the important contribution from the theoretical point of view, the results of several numerical experiments unraveled the structure of the stable zone around the librations points. This volume will be of interest to astronomers and mathematicians interested in Hamiltonian mechanics and in the dynamics of planetary systems.

  10. A complex systems methodology to transition management

    NARCIS (Netherlands)

    Alkemade, F.; Frenken, K.; Hekkert, M.P.; Schwoon, M.

    2009-01-01

    There is a general sense of urgency that major technological transitions are required for sustainable development. Such transitions are best perceived as involving multiple transition steps along a transition path. Due to the path dependent and irreversible nature of innovation in complex

  11. Equilibrium positions on stationary orbits and planetary principal inertia axis orientations for the Solar System

    Science.gov (United States)

    Romero, Pilar; Barderas, Gonzalo; Mejuto, Javier

    2018-05-01

    We present a qualitative analysis in a phase space to determine the longitudinal equilibrium positions on the planetary stationary orbits by applying an analytical model that considers linear gravitational perturbations. We discuss how these longitudes are related with the orientation of the planetary principal inertia axes with respect to their Prime Meridians, and then we use this determination to derive their positions with respect to the International Celestial Reference Frame. Finally, a numerical analysis of the non-linear effects of the gravitational fields on the equilibrium point locations is developed and their correlation with gravity field anomalies shown.

  12. Resilience Thinking as an Interdisciplinary Guiding Principle for Energy System Transitions

    Directory of Open Access Journals (Sweden)

    Frauke Wiese

    2016-09-01

    Full Text Available Resource usage and environmental consequences of most current energy systems exceed planetary boundaries. The transition to sustainable energy systems is accompanied by a multitude of research methods, as energy systems are complex structures of technical, economical, social and ecological interactions. The description of different discipline’s perspectives in this paper show that a more mutual understanding between disciplines of their respective focus is necessary as they partly create internally competitive views arising from differing emphasis of connected matters. The purpose of this paper is to present a framework for interdisciplinary proceeding in a complex energy system transition process. Resilience thinking is chosen as a core concept for a more holistic view on sustainable energy system development. It is shown that it is already widely used in different disciplines connected to energy system research and is especially suitable due to its wide application across disciplines. The seven principles of resilience thinking (maintain redundancy and diversity, manage connectivity, manage slow variables and feedback, foster complex adaptive systems thinking, encourage learning, broaden participation, and promote polycentric governance systems are chosen as the basis for a procedure that can be utilized to increase the interdisciplinary perspectives of energy system transitions. For energy transition processes based on scenario development, backcasting and pathway definition, resilience thinking principles are used to assess the resilience of the target energy system, the pathway resilience and the design of the scenario process with respect to the probability of a resilient outcome. The described procedure consisting of questions and parameters can be applied as a first attempt for a resilience assessment of energy transition processes. The perspective of resilience in sustainable energy systems strengthens the importance of diversity

  13. Vibration characteristics of two-stage planetary transmission system with thin-walled ring gear on elastic supports

    Science.gov (United States)

    Li, JianYing; Hu, QingChun; Zong, ChangFu; Zhu, TianJun; Zhang, ZeXing

    2018-03-01

    A dual-clutch and dual-speed planetary gears mechanism of a hybrid car coupled-system is taken as research subject, in which the ring gear of planet set II is a thin-walled structure and the clutch friction plates of planet set II are used as its elastic supports. Based on the lumped parameter-rigid elastic coupled dynamic model of two-stage planetary transmission system with thin-walled ring gear on elastic supports, the motion differential equations are established and the dynamic responses are solved by the Runge-Kutta method considering each stage internal and external time-varying mesh stiffness. The vibration displacements of each stage ring gear have been affected differently in time-domain, the translational vibration displacement of the ring gear of planet set I are obviously more than the torsional vibration displacement, but it is opposite for the ring gear of planet set II; The translational and torsional vibration responses of each stage ring gear arrive the peak in low-frequency. The analysis results of this paper can enrich the theoretical research of multistage planetary transmission and provide guidance for dynamic design.

  14. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

    Science.gov (United States)

    Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

    2016-01-01

    This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293

  15. Stellar and Planetary Parameters for K2 's Late-type Dwarf Systems from C1 to C5

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Arturo O. [Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States); Crossfield, Ian J. M.; Peacock, Sarah [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721 (United States); Schlieder, Joshua E. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Dressing, Courtney D. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Obermeier, Christian [Max Planck Institut für Astronomie, Heidelberg (Germany); Livingston, John; Petigura, Erik A. [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033 (Japan); Ciceri, Simona [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Beichman, Charles A. [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Lépine, Sébastien [Department of Physics and Astronomy, Georgia State University, 25 Park Pl NE #605, Atlanta, GA 30303 (United States); Aller, Kimberly M. [Institute for Astronomy, University of Hawai’i at Mānoa, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Chance, Quadry A. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85719 (United States); Howard, Andrew W. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Werner, Michael W. [Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)

    2017-03-01

    The NASA K2 mission uses photometry to find planets transiting stars of various types. M dwarfs are of high interest since they host more short-period planets than any other type of main-sequence star and transiting planets around M dwarfs have deeper transits compared to other main-sequence stars. In this paper, we present stellar parameters from K and M dwarfs hosting transiting planet candidates discovered by our team. Using the SOFI spectrograph on the European Southern Observatory’s New Technology Telescope, we obtained R ≈ 1000 J -, H -, and K -band (0.95–2.52 μ m) spectra of 34 late-type K2 planet and candidate planet host systems and 12 bright K4–M5 dwarfs with interferometrically measured radii and effective temperatures. Out of our 34 late-type K2 targets, we identify 27 of these stars as M dwarfs. We measure equivalent widths of spectral features, derive calibration relations using stars with interferometric measurements, and estimate stellar radii, effective temperatures, masses, and luminosities for the K2 planet hosts. Our calibrations provide radii and temperatures with median uncertainties of 0.059 R {sub ⊙} (16.09%) and 160 K (4.33%), respectively. We then reassess the radii and equilibrium temperatures of known and candidate planets based on our spectroscopically derived stellar parameters. Since a planet’s radius and equilibrium temperature depend on the parameters of its host star, our study provides more precise planetary parameters for planets and candidates orbiting late-type stars observed with K2 . We find a median planet radius and an equilibrium temperature of approximately 3 R {sub ⊕} and 500 K, respectively, with several systems (K2-18b and K2-72e) receiving near-Earth-like levels of incident irradiation.

  16. Comets as a possible source of nanodust in the Solar System cloud and in planetary debris discs.

    Science.gov (United States)

    Mann, Ingrid

    2017-07-13

    Comets, comet-like objects and their fragments are the most plausible source for the dust in both the inner heliosphere and planetary debris discs around other stars. The smallest size of dust particles in debris discs is not known and recent observational results suggest that the size distribution of the dust extends down to sizes of a few nanometres or a few tens of nanometres. In the Solar System, electric field measurements from spacecraft observe events that are explained with high-velocity impacts of nanometre-sized dust. In some planetary debris discs an observed mid- to near-infrared emission supposedly results from hot dust located in the vicinity of the star. And the observed emission is characteristic of dust of sizes a few tens of nanometres. Rosetta observations, on the other hand, provide little information on the presence of nanodust near comet 67P/Churyumov-Gerasimenko. This article describes why this is not in contradiction to the observations of nanodust in the heliosphere and in planetary debris discs. The direct ejection of nanodust from the nucleus of the comet would not contribute significantly to the observed nanodust fluxes. We discuss a scenario that nanodust forms in the interplanetary dust cloud through the high-velocity collision process in the interplanetary medium for which the production rates are highest near the Sun. Likewise, fragmentation by collisions occurs near the star in planetary debris discs. The collisional fragmentation process in the inner Solar System occurs at similar velocities to those of the collisional evolution in the interstellar medium. A question for future studies is whether there is a common magic size of the smallest collision fragments and what determines this size.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

  17. Gastrointestinal transit in patients with systemic sclerosis.

    Science.gov (United States)

    Fynne, Lotte; Worsøe, Jonas; Gregersen, Tine; Schlageter, Vincent; Laurberg, Søren; Krogh, Klaus

    2011-10-01

    Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis and collagen deposits. Gastrointestinal symptoms of SSc, including abdominal pain, bloating and discomfort, are common but diffuse and their pathophysiology remains obscure. To investigate the pathophysiology of abdominal pain and discomfort in individuals with SSc. A total of 15 individuals with SSc (13 women, median age 58 years), all suffering from diffuse abdominal symptoms, and 17 healthy volunteers (12 women, median age 52 years) were evaluated with the Motility Tracking System, MTS-1, measuring gastric emptying (GE) and velocity through the small intestine. SSc patients were also examined for bacterial overgrowth using the hydrogen breath test and with radiopaque markers to determine the total gastrointestinal transit time (GITT). Assessed with the MTS-1, the velocity through the proximal small intestine was significantly reduced in SSc patients (median 0.525 m/h, range 0.11-1.15) when compared to healthy subjects (median 0.91 m/h, range 0.51-1.74) (p = 0.02). Prolonged GE was found in 4 SSc patients (27%) but in none of the healthy volunteers (p = 0.04). Only 3 SSc patients (21%) had positive breath tests for small intestinal bacterial overgrowth. GITT was >3 days in 8 patients (53%). Slow small intestinal transit was associated with a prolonged GITT (p < 0.05). Velocity through the small intestine is significantly reduced in SSc patients with diffuse abdominal symptoms.

  18. HPS: A space fission power system suitable for near-term, low-cost lunar and planetary bases

    International Nuclear Information System (INIS)

    Houts, M.G.; Poston, D.I.; Ranken, W.A.

    1996-01-01

    Near-term, low-cost space fission power systems can enhance the feasibility and utility of lunar and planetary bases. One such system, the Heatpipe Power System (HPS), is described in this paper. The HPS draws on 40 yr of United States and international experience to enable a system that can be developed in <5 yr at a cost of <$100M. Total HPS mass is <600 kg at 5 kWe and <2000 kg at 50 kWe, assuming that thermoelectric power conversion is used. More advanced power conversion systems could reduce system mass significantly. System mass for planetary surface systems also may be reduced (1) if indigenous material is used for radiation shielding and (2) because of the positive effect of the gravitational field on heatpipe operation. The HPS is virtually non-radioactive at launch and is passively subcritical during all credible launch accidents. Full-system electrically heated testing is possible, and a ground nuclear power test is not needed for flight qualification. Fuel burnup limits are not reached for several decades, thus giving the system long-life potential

  19. Revolution evolution: tracing angular momentum during star and planetary system formation

    Science.gov (United States)

    Davies, Claire Louise

    2015-04-01

    disc to expand. I used spatially resolved submillimetre detections of the dust and gas components of protoplanetary discs, gathered from the literature, to measure the radial extent of discs around low-mass pre-main sequence stars of ∼ 1-10 Myr and probe their viscous evolution. I find no clear observational evidence for the radial expansion of the dust component. However, I find tentative evidence for the expansion ofthe gas component. This suggests that the evolution of the gas and dust components of protoplanetary discs are likely governed by different astrophysical processes. Observations of jets and outflows emanating from protostars and pre-main sequence stars highlight that it may also be possible to remove angular momentum from the circumstellar material. Using the sample of spatially resolved protoplanetary discs, I find no evidence for angular momentum removal during disc evolution. I also use the spatially resolved debris discs from the Submillimetre Common-User Bolometer Array-2 Observations of Nearby Stars survey to constrain the amount of angular momentum retained within planetary systems. This sample is compared to the protoplanetary disc angular momenta and to the angular momentum contained within pre-stellar cores. I find that significant quantities of angular momentum must be removed during disc formation and disc dispersal. This likely occurs via magnetic braking during the formation of the disc, via the launching of a disc or photo-evaporative wind, and/or via ejection of planetary material following dynamical interactions.

  20. BIRDY - Interplanetary CubeSat for planetary geodesy of Small Solar System Bodies (SSSB).

    Science.gov (United States)

    Hestroffer, D.; Agnan, M.; Segret, B.; Quinsac, G.; Vannitsen, J.; Rosenblatt, P.; Miau, J. J.

    2017-12-01

    We are developing the Birdy concept of a scientific interplanetary CubeSat, for cruise, or proximity operations around a Small body of the Solar System (asteroid, comet, irregular satellite). The scientific aim is to characterise the body's shape, gravity field, and internal structure through imaging and radio-science techniques. Radio-science is now of common use in planetary science (flybys or orbiters) to derive the mass of the scientific target and possibly higher order terms of its gravity field. Its application to a nano-satellite brings the advantage of enabling low orbits that can get closer to the body's surface, hence increasing the SNR for precise orbit determination (POD), with a fully dedicated instrument. Additionally, it can be applied to two or more satellites, on a leading-trailing trajectory, to improve the gravity field determination. However, the application of this technique to CubeSats in deep space, and inter-satellite link has to be proven. Interplanetary CubeSats need to overcome a few challenges before reaching successfully their deep-space objectives: link to ground-segment, energy supply, protection against radiation, etc. Besides, the Birdy CubeSat — as our basis concept — is designed to be accompanying a mothercraft, and relies partly on the main mission for reaching the target, as well as on data-link with the Earth. However, constraints to the mothercraft needs to be reduced, by having the CubeSat as autonomous as possible. In this respect, propulsion and auto-navigation are key aspects, that we are studying in a Birdy-T engineering model. We envisage a 3U size CubeSat with radio link, object-tracker and imaging function, and autonomous ionic propulsion system. We are considering two case studies for autonomous guidance, navigation and control, with autonomous propulsion: in cruise and in proximity, necessitating ΔV up to 2m/s for a total budget of about 50m/s. In addition to the propulsion, in-flight orbit determination (IFOD

  1. Exploration of Icy Moons in the Outer Solar System: Updated Planetary Protection Requirements for Missions to Enceladus and Europa

    Science.gov (United States)

    Rummel, J. D.; Race, M. S.

    2016-12-01

    Enceladus and Europa are bodies with icy/watery environments and potential habitable conditions for life, making both of great interest in astrobiological studies of chemical evolution and /or origin of life. They are also of significant planetary protection concern for spacecraft missions because of the potential for harmful contamination during exploration. At a 2015 COSPAR colloquium in Bern Switzerland, international scientists identified an urgent need to establish planetary protection requirements for missions proposing to return samples to Earth from Saturn's moon Enceladus. Deliberations at the meeting resulted in recommended policy updates for both forward and back contamination requirements for missions to Europa and Enceladus, including missions sampling plumes originating from those bodies. These recently recommended COSPAR policy revisions and biological contamination requirements will be applied to future missions to Europa and Encealadus, particularly noticeable in those with plans for in situ life detection and sample return capabilities. Included in the COSPAR policy are requirementsto `break the chain of contact' with Europa or Enceladus, to keep pristine returned materials contained, and to complete required biohazard analyses, testing and/or sterilization upon return to Earth. Subsequent to the Bern meeting, additional discussions of Planetary Protection of Outer Solar System bodies (PPOSS) are underway in a 3-year study coordinated by the European Science Foundation and involving multiple international partners, including Japan, China and Russia, along with a US observer. This presentation will provide science and policy updates for those whose research or activities will involve icy moon missions and exploration.

  2. Smart Energy Systems and Energy Transition

    International Nuclear Information System (INIS)

    Duic, N.

    2016-01-01

    Transition to decarbonized energy systems is becoming more attractive with fall of investment costs of renewables and volatile prices and political insecurity of fossil fuels. Improving energy efficiency, especially of buildings and transport, is important, but due to long life of buildings, it will be a slow way of decarbonization. The renewable energy resources are bountiful, especially wind and solar, while integrating them into current energy systems is proving to be a challenge. Solar has reached grid parity making it cheapest electricity source for retail customers in most of the World, creating new prosumer markets. It has started to reach cost parity in sunny countries, and soon solar energy will be cheapest everywhere. The limit of cheap and easy integration for wind is around 20% of yearly electricity generation, while a combined wind and solar may reach 30%. Going any further asks for implementation of completely free energy markets (involving day ahead, intraday and various reserve and ancillary services markets), demand response, coupling of wholesale and retail energy prices, and it involves integration between electricity, heat, water and transport systems. The cheapest and simplest way of increasing further the penetration of renewables is integrating power and heating/cooling systems through the use of district heating and cooling (which may be centrally controlled and may have significant heat storage capacity), since power to heat technologies are excellent for demand response. District cooling is of particular importance to historic cities that want to remove split systems from their facades. In countries with low heat demand water supply system may be used to increase the penetration of renewables, by using water at higher potential energy as storage media, or in dry climates desalination and stored water may be used for those purposes, and reversible hydro may be used as balancing technology. Electrification of personal car transport allows

  3. Planetary Geomorphology.

    Science.gov (United States)

    Baker, Victor R.

    1984-01-01

    Discusses various topics related to planetary geomorphology, including: research techniques; such geomorphic processes as impact, volcanic, degradational, eolian, and hillslope/mass movement processes; and channels and valleys. Indicates that the subject should be taught as a series of scientific questions rather than scientific results of…

  4. System Design for Transitional Aircraft Support

    Directory of Open Access Journals (Sweden)

    John P.T. Mo

    2014-01-01

    Full Text Available The Australian Defence Force and industry are undergoing significant changes in the way they work together in capability enhancement programs. There are capability gaps in maintaining and supporting current obligations during major asset acquisition, which has migrated into the front line of Royal Air Force Fighter Groups as a new capability. This paper examines a steady state support solution and argues that in order to interchange from one support solution to a new architecture there must be a period for transition, which may need its own interim business model and operational service. A preliminary study of several existing support solutions reveals the generic elements that need to be parameterized and traced through the support system architecture trajectory.

  5. The planetary scientist's companion

    CERN Document Server

    Lodders, Katharina

    1998-01-01

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

  6. TRANSIT TIMING OBSERVATIONS FROM KEPLER. IV. CONFIRMATION OF FOUR MULTIPLE-PLANET SYSTEMS BY SIMPLE PHYSICAL MODELS

    International Nuclear Information System (INIS)

    Fabrycky, Daniel C.; Ford, Eric B.; Moorhead, Althea V.; Steffen, Jason H.; Rowe, Jason F.; Christiansen, Jessie L.; Carter, Joshua A.; Fressin, Francois; Geary, John; Batalha, Natalie M.; Borucki, William J.; Bryson, Steve; Haas, Michael R.; Buchhave, Lars A.; Ciardi, David R.; Cochran, William D.; Endl, Michael; Fanelli, Michael N.; Fischer, Debra; Hall, Jennifer R.

    2012-01-01

    Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present four sets of light curves from the Kepler spacecraft, each which of shows multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates that the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets' masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems' architectures, even in cases for which high-precision Doppler follow-up is impractical.

  7. TRANSIT TIMING OBSERVATIONS FROM KEPLER. IV. CONFIRMATION OF FOUR MULTIPLE-PLANET SYSTEMS BY SIMPLE PHYSICAL MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, Santa Cruz, CA 95064 (United States); Ford, Eric B.; Moorhead, Althea V. [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32111 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, MS 127, Batavia, IL 60510 (United States); Rowe, Jason F.; Christiansen, Jessie L. [SETI Institute, Mountain View, CA 94043 (United States); Carter, Joshua A.; Fressin, Francois; Geary, John [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Borucki, William J.; Bryson, Steve; Haas, Michael R. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Buchhave, Lars A. [Department of Astrophysics and Planetary Science, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91126 (United States); Cochran, William D.; Endl, Michael [McDonald Observatory, The University of Texas, Austin TX 78730 (United States); Fanelli, Michael N. [Bay Area Environmental Research Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Fischer, Debra [Astronomy Department, Yale University, New Haven, CT (United States); Hall, Jennifer R., E-mail: daniel.fabrycky@gmail.com [Orbital Sciences Corporation/NASA Ames Research Center, Moffett Field, CA 94035 (United States); and others

    2012-05-10

    Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present four sets of light curves from the Kepler spacecraft, each which of shows multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates that the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets' masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems' architectures, even in cases for which high-precision Doppler follow-up is impractical.

  8. A Complete Approximation Theory for Weighted Transition Systems

    DEFF Research Database (Denmark)

    Hansen, Mikkel; Larsen, Kim Guldstrand; Mardare, Radu Iulian

    2016-01-01

    We propose a way of reasoning about minimal and maximal values of the weights of transitions in a weighted transition system (WTS). This perspective induces a notion of bisimulation that is coarser than the classic bisimulation: it relates states that exhibit transitions to bisimulation classes...... the image-finiteness restriction, a fact that makes this development general and robust....

  9. Note on the Tableau Technique for Commutative Transition Systems

    DEFF Research Database (Denmark)

    Srba, Jirí

    2002-01-01

    We define a class of transition systems called effective commutative transition systems (ECTS) and show, by generalising a tableau-based proof for BPP, that strong bisimilarity between any two states of such a transition system is decidable. It gives a general technique for extending decidability...... borders of strong bisimilarity for a wide class of infinite-state transition systems. This is demonstrated for several process formalisms, namely BPP process algebra, lossy BPP processes, BPP systems with interrupt and timed-arc BPP nets....

  10. Magnetic transition in double perovskite systems

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, O., E-mail: navarro@servidor.unam.m [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-360, 04510 Mexico DF (Mexico); Aguilar, B. [Laboratorio Interinstitucional de Magnetismo Natural, Instituto de Geofisica, Sede Michoacan, Universidad Nacional Autonoma de Mexico, Morelia (Mexico); Avignon, M. [Institut Neel, CNRS and Universite Joseph Fourier, BP 166, 38042 Grenoble Cedex 9 (France)

    2010-05-15

    The search for materials having complete spin polarization and high Curie temperature have received a lot of attention in view of spintronics applications, especially the ferromagnetic (F) Sr{sub 2}FeMoO{sub 6}, because of its fairly high Curie temperature (T{sub C}= 450 K), half-metallic character, large magnetoresistance and potential applications. On the other hand, Sr{sub 2}FeWO{sub 6} is insulating and antiferromagnetic (AF) with T{sub N}=37K. With a double exchange type model it has been shown that F-AF transition can be driven by super-exchange interactions with increasing Fe-M (M=Mo, W) charge transfer energy. So, the charge transfer energy is expected to be larger in FeW than in FeMo compounds. Using a tight-binding model with the renormalized perturbation expansion technique, we determine the density of states for the AF phase and the electronic energy difference for the F- and AF-phases as a function of the Fe-M charge transfer energy. The F-AF transition in the ordered system Sr{sub 2}FeMo{sub x}W{sub 1-x}O{sub 6} occurs for xapprox0.3, in good agreement with the experimental value. We also studied the effect of the diagonal disorder in the variation of the number of conduction electrons on Fe and M sites. Finally, the behavior of the Curie temperature as a function of the Mo/W concentration is determined.

  11. Nuclear safeguards - a system in transition

    International Nuclear Information System (INIS)

    Carlson, J.

    1999-01-01

    'Classical' safeguards have a strong emphasis on nuclear materials accountancy, and are primarily concerned with verifying nuclear activities as declared by the State - what has been termed the correctness of States' declarations. Following the Gulf War, failure to adequately address the possibility of undeclared nuclear activities - the issue of the completeness of States' declarations - has been recognised as a major shortcoming in the classical safeguards system, and major changes are in progress to strengthen the IAEA's capabilities in this regard. Agreement has been reached on a Model Protocol substantially extending the IAEA's authority, and there has been good progress in developing the new approaches and technologies required to ensure this authority is used effectively. IAEA safeguards are undergoing a major transition, towards greater emphasis on information collection and analysis, diversity of verification methods, incorporation of more qualitative judgments, and improved efficiency. These changes present major challenges to the IAEA and to the international community, but the end result will be a more effective safeguards system

  12. Role of the magnetospheric convection and inertial forces informing the planetary structure of the ionosphere-protonosphere system

    International Nuclear Information System (INIS)

    Saenko, Yu.S.; Natsvalyan, N.S.; Tepenitsyna, N.Yu.; Shagimuratov, I.I.

    1991-01-01

    Mechanisms of forming the planetary distribution of concentrations and fluxes of basic O + and H + ions are investigated on the base of a three-dimensional nonstationary model of ionosphere-protonosphere system. The leading role of diffusion, drifts and inertia in the formation of such structural features as equatorial anomaly, mid-latitudinal gap, polar tail in F2-layer and plasmosphere, plasmosphere, plasma gap and polar wind in protonosphere, as well as regions with increased concentrations of heavy O + ions in the polar wind and plasmosphere, is demonstrated

  13. The (Un)Lonely Planet Guide: Formation and Evolution of Planetary Systems from a ``Blue Dots'' Perspective

    Science.gov (United States)

    Meyer, M. R.

    2010-10-01

    In this contribution I summarize some recent successes, and focus on remaining challenges, in understanding the formation and evolution of planetary systems in the context of the Blue Dots initiative. Because our understanding is incomplete, we cannot yet articulate a design reference mission engineering matrix suitable for an exploration mission where success is defined as obtaining a spectrum of a potentially habitable world around a nearby star. However, as progress accelerates, we can identify observational programs that would address fundamental scientific questions through hypothesis testing such that the null result is interesting.

  14. Implementing planetary protection on the Atlas V fairing and ground systems used to launch the Mars Science Laboratory.

    Science.gov (United States)

    Benardini, James N; La Duc, Myron T; Ballou, David; Koukol, Robert

    2014-01-01

    On November 26, 2011, the Mars Science Laboratory (MSL) launched from Florida's Cape Canaveral Air Force Station aboard an Atlas V 541 rocket, taking its first step toward exploring the past habitability of Mars' Gale Crater. Because microbial contamination could profoundly impact the integrity of the mission, and compliance with international treaty was a necessity, planetary protection measures were implemented on all MSL hardware to verify that bioburden levels complied with NASA regulations. The cleanliness of the Atlas V payload fairing (PLF) and associated ground support systems used to launch MSL were also evaluated. By applying proper recontamination countermeasures early and often in the encapsulation process, the PLF was kept extremely clean and was shown to pose little threat of recontaminating the enclosed MSL flight system upon launch. Contrary to prelaunch estimates that assumed that the interior PLF spore burden ranged from 500 to 1000 spores/m², the interior surfaces of the Atlas V PLF were extremely clean, housing a mere 4.65 spores/m². Reported here are the practices and results of the campaign to implement and verify planetary protection measures on the Atlas V launch vehicle and associated ground support systems used to launch MSL. All these facilities and systems were very well kept and exceeded the levels of cleanliness and rigor required in launching the MSL payload.

  15. Calcium signals in planetary embryos

    Science.gov (United States)

    Morbidelli, Alessandro

    2018-03-01

    The calcium-isotope composition of planetary bodies in the inner Solar System correlates with the masses of such objects. This finding could have implications for our understanding of how the Solar System formed.

  16. Geodesy and cartography methods of exploration of the outer planetary systems: Galilean satellites and Enceladus

    Science.gov (United States)

    Zubarev, Anatoliy; Kozlova, Natalia; Kokhanov, Alexander; Oberst, Jürgen; Nadezhdina, Irina; Patraty, Vyacheslav; Karachevtseva, Irina

    elements of external orientation, provides new image processing of previous missions to outer planetary system. Using Photomod software (http://www.racurs.ru/) we have generated a new control point network in 3-D and orthomosaics for Io, Ganymede and Enceladus. Based on improved orbit data for Galileo we have used larger numbers of images than were available before, resulting in a more rigid network for Ganymede. The obtained results will be used for further processing and improvement of the various parameters: body shape parameters and shape modeling, libration, as well as for studying of the surface interesting geomorphological phenomena, for example, distribution of bright and dark surface materials on Ganymede and their correlations with topography and slopes [6]. Acknowledgments: The Ganymede study was partly supported by ROSKOSMOS and Space Research Institute under agreement No. 36/13 “Preliminary assessment of the required coordinate and navigation support for selection of landing sites for lander mission “Laplace” and partly funding by agreement No. 11-05-91323 for “Geodesy, cartography and research satellites Phobos and Deimos” References: [1] Nadezhdina et al. Vol. 14, EGU2012-11210, 2012. [2] Zhukov et al. International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments", Space Research Institute, Moscow, Russia, 4-8 March, 2013. [3] Zubarev et al. International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments", Space Research Institute, Moscow, Russia, 4-8 March, 2013. [4] Lazarev et al. Izvestia VUZov. 2012, No 6, pp. 9-11 http://miigaik.ru/journal.miigaik.ru/2012/20130129120215-2593.pdf (in Russian). [5] Kokhanov et al. Current problems in remote sensing of the Earth from space. 2013. Vol. 10. No 4. pp. 136-153. http://d33.infospace.ru/d33_conf/sb2013t4/136-153.pdf (in Russian). [6] Oberst et al., 2013 International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments", Space

  17. Agile Port System Transition Support Transition Plan Development

    Science.gov (United States)

    2013-07-29

    the term agile port like  coca   cola  having migrated to the national lexicon in ubiquitous general usage.  For its part the JDDSP concept has evolved...RTLS technology is a COTS patented technology and TrAMS technology is owned by CSUOB  Foundation. Neither is in a  financial  position to invest in...acquisition and  systems engineering principles.   Cost    X    A focused effort would require dedication of adequate in kind and  financial  DoD resources

  18. Bifurcation of transition paths induced by coupled bistable systems.

    Science.gov (United States)

    Tian, Chengzhe; Mitarai, Namiko

    2016-06-07

    We discuss the transition paths in a coupled bistable system consisting of interacting multiple identical bistable motifs. We propose a simple model of coupled bistable gene circuits as an example and show that its transition paths are bifurcating. We then derive a criterion to predict the bifurcation of transition paths in a generalized coupled bistable system. We confirm the validity of the theory for the example system by numerical simulation. We also demonstrate in the example system that, if the steady states of individual gene circuits are not changed by the coupling, the bifurcation pattern is not dependent on the number of gene circuits. We further show that the transition rate exponentially decreases with the number of gene circuits when the transition path does not bifurcate, while a bifurcation facilitates the transition by lowering the quasi-potential energy barrier.

  19. PLANETS AROUND LOW-MASS STARS (PALMS). IV. THE OUTER ARCHITECTURE OF M DWARF PLANETARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Bowler, Brendan P. [California Institute of Technology, Division of Geological and Planetary Sciences, 1200 East California Boulevard, Pasadena, CA 91101 (United States); Liu, Michael C. [Institute for Astronomy, University of Hawai' i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Tamura, Motohide, E-mail: bpbowler@caltech.edu [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2015-01-01

    to single M dwarfs between 10-100 AU is 2.8{sub −1.5}{sup +2.4}%. Altogether we find that giant planets, especially massive ones, are rare in the outskirts of M dwarf planetary systems. Although the first directly imaged planets were found around massive stars, there is currently no statistical evidence for a trend of giant planet frequency with stellar host mass at large separations as predicted by the disk instability model of giant planet formation.

  20. Liquid-liquid phase transition and glass transition in a monoatomic model system.

    Science.gov (United States)

    Xu, Limei; Buldyrev, Sergey V; Giovambattista, Nicolas; Stanley, H Eugene

    2010-01-01

    We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

  1. Computer studies of the evolution of planetary and satellite systems. II

    International Nuclear Information System (INIS)

    Barricelli, N.A.; Aashamar, K.

    1980-01-01

    This paper describes two computer experiments carried out with a CDC-Cyber 74 program for computer simulation of a large number of objects in orbit about a central body or primary. The first experiment was started with 125 planets of which the two largest ones had coplanar orbits and masses comparable to those of Jupiter and Saturn, respectively. Their semi-major axes and eccentricities were, however, much larger. The smaller planets had a distribution promoting the formation of an axial meeting area. The experiment gives information relevant to the question of focusing of planetary orbits into a common plane and to the question of the formation and stability of an axial meeting area. Together with the next experiment, it also gives information about the development of commensurabilities (or resonances) with the largest planets. The second experiment started with 55 planets none of them with a mass greater than about 20% of Jupiter's but several of them with orbits close to a common plane. The aim of the experiment was to investigate whether successive captures followed by planetary fusion could lead to the formation of major planets comparable to Jupiter and Saturn, and in similar orbits. Also this experiment gives information relevant to the commensurability problem. (Auth.)

  2. Quantum phase transitions of strongly correlated electron systems

    International Nuclear Information System (INIS)

    Imada, Masatoshi

    1998-01-01

    Interacting electrons in solids undergo various quantum phase transitions driven by quantum fluctuations. The quantum transitions take place at zero temperature by changing a parameter to control quantum fluctuations rather than thermal fluctuations. In contrast to classical phase transitions driven by thermal fluctuations, the quantum transitions have many different features where quantum dynamics introduces a source of intrinsic fluctuations tightly connected with spatial correlations and they have been a subject of recent intensive studies as we see below. Interacting electron systems cannot be fully understood without deep analyses of the quantum phase transitions themselves, because they are widely seen and play essential roles in many phenomena. Typical and important examples of the quantum phase transitions include metal-insulator transitions, (2, 3, 4, 5, 6, 7, 8, 9) metal-superconductor transitions, superconductor-insulator transitions, magnetic transitions to antiferromagnetic or ferromagnetic phases in metals as well as in Mott insulators, and charge ordering transitions. Here, we focus on three different types of transitions

  3. Hidden Challenges to Education Systems in Transition Economies.

    Science.gov (United States)

    Berryman, Sue E.

    This book, published by the World Bank, sounds the alarm for education in Europe and Central Asia (ECA). It describes how the transition from communism to free-market economies has left many countries' educational systems in disarray. At the start of transition, ECA education systems had solved problems that plagued other regions of the world,…

  4. Accelerating the transition to sustainable energy systems

    International Nuclear Information System (INIS)

    Jefferson, Michael

    2008-01-01

    The slow pace of transition to sustainable energy systems is the result of several factors running in parallel. The starting points are very low. Even 30% per annum increases in rated capacity (for wind energy or solar PV, for example) take many years to make a big impact at the global level. Policy initiatives are for the most part ineffectual in relation to the urgency and scale of what is required, and often fail to address the fundamental causes of this slow progress. This reflects a 'top-down' approach-often accompanied by unrealistic targets and simultaneously undermined by a lack of consistency across policies, which reflect a 'utopian social engineering mentality', made worse because: 'The Planner's response to failure of previous interventions (is) to do more intensive and comprehensive interventions' as William Easterly has put it. In short, there is little or no accountability. This approach has failed to harness the sympathy, imagination, self-interest, or sound options of energy users-although it may attract developers, including those not hitherto noted for renewable energy projects or environmental concern. Targets are usually too short term and clearly unrealistic, especially where fossil fuel use is rising very rapidly, and renewable energy use expands modestly. Government subsidies for traditional energy forms continue. Insufficient attention is paid to what individuals might achieve in energy efficiency and renewable energy terms if permitted to have, or retain (in industrialized countries, where the burden of taxation is often inhibiting), the wherewithal to make the necessary investments. Subsidy systems often promote renewable energy schemes that are misdirected and buoyed up by grossly exaggerated claims. One or two mature renewable energy technologies are pushed nationally with insufficient regard for their costs, contribution to electricity generation, transportation fuels' needs, or carbon emission avoidance. Investors are rewarded

  5. PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Moynier, Frederic; Podosek, Frank A. [Department of Earth and Planetary Science and McDonnell Center for Space Sciences, Washington University, St. Louis, MO 63130 (United States); Day, James M. D. [Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0244 (United States); Okui, Wataru; Yokoyama, Tetsuya [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Bouvier, Audrey [Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455-0231 (United States); Walker, Richard J., E-mail: moynier@levee.wustl.edu, E-mail: fap@levee.wustl.edu, E-mail: jmdday@ucsd.edu, E-mail: rjwalker@umd.edu, E-mail: okui.w.aa@m.titech.ac.jp, E-mail: tetsuya.yoko@geo.titech.ac.jp, E-mail: abouvier@umn.edu [Department of Geology, University of Maryland, College Park, MD 20742 (United States)

    2012-10-10

    Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived {sup 87}Rb-{sup 87}Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial {sup 87}Sr/{sup 86}Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in {sup 84}Sr/{sup 86}Sr between calcium aluminum inclusions and eucrites ({epsilon}{sup 84}Sr > 2), the difference in age between these materials would be {approx}6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.

  6. Future planetary X-ray and gamma-ray remote sensing system and in situ requirements for room temperature solid state detectors

    CERN Document Server

    Trombka, J I; Starr, R; Clark, P E; Floyd, S R

    1999-01-01

    X-Ray and gamma-ray remote sensing observations find important applications in the study of the development of the planets. Orbital measurements can be carried out on solar-system bodies whose atmospheres and trapped radiation environments do not interfere significantly with the emissions. Elemental compositions can be inferred from observations of these line emissions. Future planetary missions also will involve landing both stationery and roving probes on planetary surfaces. Both X-ray and gamma-ray spectrometers will be used for performing elemental analysis of surface samples. These future planetary missions will impose a number of constraints: the flight instruments must be significantly reduced in weight from those previously flown; for many missions, gravity assist will be required, greatly increasing mission duration, resulting in the passage of several years before the first scientific measurement of a solar system body. The detector systems must operate reliably after years of cosmic-ray irradiation...

  7. Transit Timing Observations from Kepler: II. Confirmation of Two Multiplanet Systems via a Non-parametric Correlation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Eric B.; /Florida U.; Fabrycky, Daniel C.; /Lick Observ.; Steffen, Jason H.; /Fermilab; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Moorhead, Althea V.; /Florida U.; Morehead, Robert C.; /Florida U.; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Rowe, Jason F.; /NASA, Ames /SETI Inst., Mtn. View /San Diego State U., Astron. Dept.

    2012-01-01

    We present a new method for confirming transiting planets based on the combination of transit timing variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the transit timing variations of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:9 and 2:4:6:9 period commensurabilities. Our results demonstrate that TTVs provide a powerful tool for confirming transiting planets, including low-mass planets and planets around faint stars for which Doppler follow-up is not practical with existing facilities. Continued Kepler observations will dramatically improve the constraints on the planet masses and orbits and provide sensitivity for detecting additional non-transiting planets. If Kepler observations were extended to eight years, then a similar analysis could likely confirm systems with multiple closely spaced, small transiting planets in or near the habitable zone of solar-type stars.

  8. Planetary Science Training for NASA's Astronauts: Preparing for Future Human Planetary Exploration

    Science.gov (United States)

    Bleacher, J. E.; Evans, C. A.; Graff, T. G.; Young, K. E.; Zeigler, R.

    2017-02-01

    Astronauts selected in 2017 and in future years will carry out in situ planetary science research during exploration of the solar system. Training to enable this goal is underway and is flexible to accommodate an evolving planetary science vision.

  9. Rock mass classification system : transition from RMR to GSI.

    Science.gov (United States)

    2013-11-01

    The AASHTO LRFD Bridge Design Specifications is expected to replace the rock mass rating : (RMR) system with the Geological Strength Index (GSI) system for classifying and estimating : engineering properties of rock masses. This transition is motivat...

  10. Sciences for Exoplanets and Planetary Systems : web sites and E-learning

    Science.gov (United States)

    Roques, F.; Balança, C.; Bénilan, Y.; Griessmeier, J. M.; Marcq, E.; Navarro, T.; Renner, S.; Schneider, J.; Schott, C.

    2015-10-01

    The websites « Sciences pour les Exoplanètes et les Systèmes Planétaires » (SESP) and « Exoplanètes » have been created in the context of the LabEx ESEP (Laboratoire d'excellence Exploration Spatiale des Environnements Planétaires) [1]. They present planetary and exoplanetary sciences with courses, interactive tools, and a didactic catalogue connected to the Encyclopedia http://exoplanet.eu [2]. These resources are directed towards undergraduate level. They will be used as support for face-to-face courses and self-training. In the future, we will translate some contents into English and create e-learning degree courses.

  11. Long Term Evolution of Planetary Systems with a Terrestrial Planet and a Giant Planet

    Science.gov (United States)

    Georgakarakos, Nikolaos; Dobbs-Dixon, Ian; Way, Michael J.

    2016-01-01

    We study the long term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the smaller planet. The perturbing potential is expanded to high orders and an analytical solution of the terrestrial planetary orbit is derived. The analytical estimates are then compared against results from the numerical integration of the full equations of motion and we find that the analytical solution works reasonably well. An interesting finding is that the new analytical estimates improve greatly the predictions for the timescales of the orbital evolution of the terrestrial planet compared to an octupole order expansion. Finally, we briefly discuss possible applications of the analytical estimates in astrophysical problems.

  12. Health system strategies supporting transition to adult care.

    Science.gov (United States)

    Hepburn, Charlotte Moore; Cohen, Eyal; Bhawra, Jasmin; Weiser, Natalie; Hayeems, Robin Z; Guttmann, Astrid

    2015-06-01

    The transition from paediatric to adult care is associated with poor clinical outcomes, increased costs and low patient and family satisfaction. However, little is known about health system strategies to streamline and safeguard care for youth transitioning to adult services. Moreover, the needs of children and youth are often excluded from broader health system reform discussions, leaving this population especially vulnerable to system 'disintegration'. (1) To explore the international policy profile of paediatric-to-adult care transitions, and (2) to document policy objectives, initiatives and outcomes for jurisdictions publicly committed to addressing transition issues. An international policy scoping review of all publicly available government documents detailing transition-related strategies was completed using a web-based search. Our analysis included a comparable cohort of nine wealthy Organisation for Economic Co-operation and Development (OECD) jurisdictions with Beveridge-style healthcare systems (deemed those most likely to benefit from system-level transition strategies). Few jurisdictions address transition of care issues in either health or broader social policy documents. While many jurisdictions refer to standardised practice guidelines, a few report the intention to use powerful policy levers (including physician remuneration and non-physician investments) to facilitate the uptake of best practice. Most jurisdictions do not address the policy infrastructure required to support successful transitions, and rigorous evaluations of transition strategies are rare. Despite the well-documented risks and costs associated with a poor transition from paediatric to adult care, little policy attention has been paid to this issue. We recommend that healthcare providers engage health system planners in the design and evaluation of system-level, policy-sensitive transition strategies. Published by the BMJ Publishing Group Limited. For permission to use (where not

  13. TRANSIT OBSERVATIONS OF THE WASP-10 SYSTEM

    International Nuclear Information System (INIS)

    Dittmann, J. A.; Close, L. M.; Scuderi, L. J.; Morris, M. D.

    2010-01-01

    We present here observations of the transit of WASP-10b on 2009 October 14 UT taken from the University of Arizona's 1.55 m Kuiper telescope on Mount Bigelow. Conditions were photometric and accuracies of 2.0 mmag rms were obtained throughout the transit. We have found that the ratio of the planet to host star radii is in agreement with the measurements of Christian et al. instead of the refinements of Johnson et al., suggesting that WASP-10b is indeed inflated beyond what is expected from theoretical modeling. We find no evidence for large (>20 s) transit timing variations in WASP-10b's orbit from the ephemeris of Christian et al. and Johnson et al.

  14. Planetary Habitability

    Science.gov (United States)

    Kasting, James F.

    1997-01-01

    This grant was entitled 'Planetary Habitability' and the work performed under it related to elucidating the conditions that lead to habitable, i.e. Earth-like, planets. Below are listed publications for the past two and a half years that came out of this work. The main thrusts of the research involved: (1) showing under what conditions atmospheric O2 and O3 can be considered as evidence for life on a planet's surface; (2) determining whether CH4 may have played a role in warming early Mars; (3) studying the effect of varying UV levels on Earth-like planets around different types of stars to see whether this would pose a threat to habitability; and (4) studying the effect of chaotic obliquity variations on planetary climates and determining whether planets that experienced such variations might still be habitable. Several of these topics involve ongoing research that has been carried out under a new grant number, but which continues to be funded by NASA's Exobiology program.

  15. Shaping of planetary nebulae

    International Nuclear Information System (INIS)

    Balick, B.

    1987-01-01

    The phases of stellar evolution and the development of planetary nebulae are examined. The relation between planetary nebulae and red giants is studied. Spherical and nonspherical cases of shaping planetaries with stellar winds are described. CCD images of nebulae are analyzed, and it is determined that the shape of planetary nebulae depends on ionization levels. Consideration is given to calculating the distances of planetaries using radio images, and molecular hydrogen envelopes which support the wind-shaping model of planetary nebulae

  16. Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system.

    Science.gov (United States)

    Worsøe, Jonas; Fynne, Lotte; Gregersen, Tine; Schlageter, Vincent; Christensen, Lisbet A; Dahlerup, Jens F; Rijkhoff, Nico J M; Laurberg, Søren; Krogh, Klaus

    2011-12-29

    Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4) giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, φ). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state. Experiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1) (p = 0.03). MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

  17. Non-planetary Science from Planetary Missions

    Science.gov (United States)

    Elvis, M.; Rabe, K.; Daniels, K.

    2015-12-01

    Planetary science is naturally focussed on the issues of the origin and history of solar systems, especially our own. The implications of an early turbulent history of our solar system reach into many areas including the origin of Earth's oceans, of ores in the Earth's crust and possibly the seeding of life. There are however other areas of science that stand to be developed greatly by planetary missions, primarily to small solar system bodies. The physics of granular materials has been well-studied in Earth's gravity, but lacks a general theory. Because of the compacting effects of gravity, some experiments desired for testing these theories remain impossible on Earth. Studying the behavior of a micro-gravity rubble pile -- such as many asteroids are believed to be -- could provide a new route towards exploring general principles of granular physics. These same studies would also prove valuable for planning missions to sample these same bodies, as techniques for anchoring and deep sampling are difficult to plan in the absence of such knowledge. In materials physics, first-principles total-energy calculations for compounds of a given stoichiometry have identified metastable, or even stable, structures distinct from known structures obtained by synthesis under laboratory conditions. The conditions in the proto-planetary nebula, in the slowly cooling cores of planetesimals, and in the high speed collisions of planetesimals and their derivatives, are all conditions that cannot be achieved in the laboratory. Large samples from comets and asteroids offer the chance to find crystals with these as-yet unobserved structures as well as more exotic materials. Some of these could have unusual properties important for materials science. Meteorites give us a glimpse of these exotic materials, several dozen of which are known that are unique to meteorites. But samples retrieved directly from small bodies in space will not have been affected by atmospheric entry, warmth or

  18. TRANSIT TIMING OBSERVATIONS FROM KEPLER. II. CONFIRMATION OF TWO MULTIPLANET SYSTEMS VIA A NON-PARAMETRIC CORRELATION ANALYSIS

    International Nuclear Information System (INIS)

    Ford, Eric B.; Moorhead, Althea V.; Morehead, Robert C.; Fabrycky, Daniel C.; Steffen, Jason H.; Carter, Joshua A.; Fressin, Francois; Holman, Matthew J.; Ragozzine, Darin; Charbonneau, David; Lissauer, Jack J.; Rowe, Jason F.; Borucki, William J.; Bryson, Stephen T.; Burke, Christopher J.; Caldwell, Douglas A.; Welsh, William F.; Allen, Christopher; Batalha, Natalie M.; Buchhave, Lars A.

    2012-01-01

    We present a new method for confirming transiting planets based on the combination of transit timing variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies is in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the TTVs of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple-planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:9 and 2:4:6:9 period commensurabilities. Our results demonstrate that TTVs provide a powerful tool for confirming transiting planets, including low-mass planets and planets around faint stars for which Doppler follow-up is not practical with existing facilities. Continued Kepler observations will dramatically improve the constraints on the planet masses and orbits and provide sensitivity for detecting additional non-transiting planets. If Kepler observations were extended to eight years, then a similar analysis could likely confirm systems with multiple closely spaced, small transiting planets in or near the habitable zone of solar-type stars.

  19. TRANSIT TIMING OBSERVATIONS FROM KEPLER. II. CONFIRMATION OF TWO MULTIPLANET SYSTEMS VIA A NON-PARAMETRIC CORRELATION ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Eric B.; Moorhead, Althea V.; Morehead, Robert C. [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32611 (United States); Fabrycky, Daniel C. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, MS 127, Batavia, IL 60510 (United States); Carter, Joshua A.; Fressin, Francois; Holman, Matthew J.; Ragozzine, Darin; Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lissauer, Jack J.; Rowe, Jason F.; Borucki, William J.; Bryson, Stephen T.; Burke, Christopher J.; Caldwell, Douglas A. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Welsh, William F. [Astronomy Department, San Diego State University, San Diego, CA 92182-1221 (United States); Allen, Christopher [Orbital Sciences Corporation/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Buchhave, Lars A., E-mail: eford@astro.ufl.edu [Niels Bohr Institute, Copenhagen University, DK-2100 Copenhagen (Denmark); Collaboration: Kepler Science Team; and others

    2012-05-10

    We present a new method for confirming transiting planets based on the combination of transit timing variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies is in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the TTVs of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple-planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:9 and 2:4:6:9 period commensurabilities. Our results demonstrate that TTVs provide a powerful tool for confirming transiting planets, including low-mass planets and planets around faint stars for which Doppler follow-up is not practical with existing facilities. Continued Kepler observations will dramatically improve the constraints on the planet masses and orbits and provide sensitivity for detecting additional non-transiting planets. If Kepler observations were extended to eight years, then a similar analysis could likely confirm systems with multiple closely spaced, small transiting planets in or near the habitable zone of solar-type stars.

  20. The formation of retrograde planetary orbits by close stellar encounters

    Directory of Open Access Journals (Sweden)

    Ford E. B.

    2011-02-01

    Full Text Available We consider the growing number of observations of the RossiterMcLaughlin effect in transiting planets, which seem to suggest that ~30% of transiting planets are in highly inclined or retrograde orbits. We consider the dense cluster environment in which stars are born and investigate whether perturbations from passing stars can drive planetary systems into retrograde configurations. We find that fly-bys can result in significantly more inclination excitation than might naively be expected from impulse approximations, leading to several percent of stellar systems possessing planets in retrograde orbits.

  1. Transition towards Circular Economy in the Food System

    Directory of Open Access Journals (Sweden)

    Alexandra Jurgilevich

    2016-01-01

    Full Text Available Growing population and increased demand for food, inefficient resource use and food distribution, environmental impacts, and high rates of food wasted at all stages of the food system are all calling for transition towards more sustainable practices. In this article we apply the concept of circular economy to the case of a sustainable food system. Furthermore, we explore the transition towards a circular food system through the lens of socio-technical transition theory towards sustainability. We discuss challenges and potential solutions for the production stage (focusing on nutrient flow, the consumption stage (focusing on meat consumption, and food waste and surplus management and prevention.

  2. Challenging the planetary boundaries II: Assessing the sustainable global population and phosphate supply, using a systems dynamics assessment model

    International Nuclear Information System (INIS)

    Sverdrup, Harald U.; Ragnarsdottir, Kristin Vala

    2011-01-01

    Highlights: → Peak phosphorus supply behaviour. → Recycling essential for phosphorus supply. → Phosphorus supply is connected to food security. - Abstract: A systems dynamics model was developed to assess the planetary boundary for P supply in relation to use by human society. It is concluded that present day use rates and poor recycling rates of P are unsustainable at timescales beyond 100+ a. The predictions made suggest that P will become a scarce and expensive material in the future. The study shows clearly that market mechanisms alone will not be able to secure an efficient use before a large part of the resource will have been allowed to dissipate into the natural environment. It is suggested that population size management and effective recycling measures must be planned long term to avoid unpleasant consequences of hunger and necessary corrections imposed on society by mass balance and thermodynamics.

  3. A New Paradigm for Habitability in Planetary Systems: the Extremophilic Zone

    Science.gov (United States)

    Janot-Pacheco, E., Bernardes, L., Lage, C. A. S.

    2014-03-01

    More than a thousand exoplanets have been discovered so far. Planetary surface temperature may strongly depends on its albedo and geodynamic conditions. We have fed exoplanets from the Encyclopedia database with a comprehensive model of Earth's atmosphere and plate tectonics. As CO2 is the main agent responsible for the greenhouse effect, its partial pressure has been taken as a free parameter to estimate the surface temperature of some known planets. We also investigated the possible presence of "exomoons" belonging to giant planets in the Habitable Zone capable of harbour dynamic stability, to retain an atmosphere and to keep geodynamic activity for long time spans. Biological data on earthly micro-organisms classified as "extremophiles" indicate that such kind of microbial species could dwell on the surface of many exoplanets and exomoons. We thus propose an extension of the mainly astronomically defined "Habitable Zone" concept into the more astrobiologically one, the "Extremophililic Zone", that takes into account other parameters allowing survival of more robust life forms. This contribution comes from an ongoing project developed by a French-Brazilian colaboration in Astrophysics and Biophysics to search for living fingerprints in astrobiologically promising exoplanets.

  4. Orbital alignment and star-spot properties in the WASP-52 planetary system

    DEFF Research Database (Denmark)

    Mancini, L.; Southworth, J.; Raia, G.

    2017-01-01

    the same site but with two different instruments, including a multi-band camera. Anomalies were clearly detected in five light curves and modelled as starspots occulted by the planet during the transit events. We fitted the clean light curves with the jktebop code, and those with the anomalies...

  5. THE KEPLER-19 SYSTEM: A TRANSITING 2.2 R{sub Circled-Plus} PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, Sarah; Fressin, Francois; Charbonneau, David; Desert, Jean-Michel; Torres, Guillermo; Holman, Matthew J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fabrycky, Daniel [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Marcy, Geoffrey; Isaacson, Howard [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States); Burke, Christopher J.; Henze, Christopher; Howell, Steven B.; Bryson, Stephen T.; Rowe, Jason F.; Lissauer, Jack J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, Batavia, IL 60510 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Cochran, William D.; Endl, Michael [McDonald Observatory, The University of Texas, Austin, TX 78712 (United States); Jenkins, Jon M., E-mail: sballard@cfa.harvard.edu [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); and others

    2011-12-20

    We present the discovery of the Kepler-19 planetary system, which we first identified from a 9.3 day periodic transit signal in the Kepler photometry. From high-resolution spectroscopy of the star, we find a stellar effective temperature T{sub eff} = 5541 {+-} 60 K, a metallicity [Fe/H] = -0.13 {+-} 0.06, and a surface gravity log(g) = 4.59 {+-} 0.10. We combine the estimate of T{sub eff} and [Fe/H] with an estimate of the stellar density derived from the photometric light curve to deduce a stellar mass of M{sub *} = 0.936 {+-} 0.040 M{sub Sun} and a stellar radius of R{sub *} = 0.850 {+-} 0.018 R{sub Sun} (these errors do not include uncertainties in the stellar models). We rule out the possibility that the transits result from an astrophysical false positive by first identifying the subset of stellar blends that reproduce the precise shape of the light curve. Using the additional constraints from the measured color of the system, the absence of a secondary source in the high-resolution spectrum, and the absence of a secondary source in the adaptive optics imaging, we conclude that the planetary scenario is more than three orders of magnitude more likely than a blend. The blend scenario is independently disfavored by the achromaticity of the transit: we measure a transit depth with Spitzer at 4.5 {mu}m of 547{sup +113}{sub -110} ppm, consistent with the depth measured in the Kepler optical bandpass of 567 {+-} 6 ppm (corrected for stellar limb darkening). We determine a physical radius of the planet Kepler-19b of R{sub p} = 2.209 {+-} 0.048 R{sub Circled-Plus }; the uncertainty is dominated by uncertainty in the stellar parameters. From radial velocity observations of the star, we find an upper limit on the planet mass of 20.3 M{sub Circled-Plus }, corresponding to a maximum density of 10.4 g cm{sup -3}. We report a significant sinusoidal deviation of the transit times from a predicted linear ephemeris, which we conclude is due to an additional perturbing body in

  6. Construction of the Hunveyor-Husar space probe model system for planetary science education and analog studies and simulations in universities and colleges of Hungary.

    Science.gov (United States)

    Bérczi, Sz.; Hegyi, S.; Hudoba, Gy.; Hargitai, H.; Kokiny, A.; Drommer, B.; Gucsik, A.; Pintér, A.; Kovács, Zs.

    Several teachers and students had the possibility to visit International Space Camp in the vicinity of the MSFC NASA in Huntsville Alabama USA where they learned the success of simulators in space science education To apply these results in universities and colleges in Hungary we began a unified complex modelling in planetary geology robotics electronics and complex environmental analysis by constructing an experimental space probe model system First a university experimental lander HUNVEYOR Hungarian UNiversity surVEYOR then a rover named HUSAR Hungarian University Surface Analyser Rover has been built For Hunveyor the idea and example was the historical Surveyor program of NASA in the 1960-ies for the Husar the idea and example was the Pathfinder s rover Sojouner rover The first step was the construction of the lander a year later the rover followed The main goals are 1 to build the lander structure and basic electronics from cheap everyday PC compatible elements 2 to construct basic experiments and their instruments 3 to use the system as a space activity simulator 4 this simulator contains lander with on board computer for works on a test planetary surface and a terrestrial control computer 5 to harmonize the assemblage of the electronic system and instruments in various levels of autonomy from the power and communication circuits 6 to use the complex system in education for in situ understanding complex planetary environmental problems 7 to build various planetary environments for application of the

  7. Transition Office Management and Accounting System

    Data.gov (United States)

    US Agency for International Development — TOMAS combined over 20 previously separate systems into one fully integrated management system covering budget, finance, procurement, travel, and emergency contact...

  8. Renormalization group theory of phase transitions in square Ising systems

    International Nuclear Information System (INIS)

    Nienhuis, B.

    1978-01-01

    Some renormalization group calculations are presented on a number of phase transitions in a square Ising model, both second and first order. Of these transitions critical exponents are calculated, the amplitudes of the power law divergences and the locus of the transition. In some cases attention is paid to the thermodynamic functions also far from the critical point. Universality and scaling are discussed and the renormalization group theory is reviewed. It is shown how a renormalization transformation, which relates two similar systems with different macroscopic dimensions, can be constructed, and how some critical properties of the system follow from this transformation. Several numerical and analytical applications are presented. (Auth.)

  9. System and prospects of China's intercity rail transit technology

    Science.gov (United States)

    Gong, Ming

    2018-06-01

    City clusters and metropolitan areas in China are flourishing in the midst of the deepening urbanization in the country, thereby resulting in the emergence of intercity rail transit. Intercity railways connect mainline and urban railways for an integrated regional transportation system that underpins and leads the development of city clusters and metropolitan areas. This study explores the development mode and service characteristics of intercity rail transit, as well as proposes overviews on this system and prospects of its future technology in China.

  10. A Decidable Recursive Logic for Weighted Transition Systems

    DEFF Research Database (Denmark)

    Xue, Bingtian; Larsen, Kim Guldstrand; Mardare, Radu Iulian

    2014-01-01

    In this paper we develop and study the Recursive Weighted Logic (RWL), a multi-modal logic that expresses qualitative and quantitative properties of labelled weighted transition systems (LWSs). LWSs are transition systems labelled with actions and real-valued quantities representing the costs of ...... extends previous results that we have demonstrated for a similar but much more restrictive logic that can only use one variable for each type of resource to encode logical properties....

  11. EPOXI EXOPLANET TRANSIT OBS - HRIV CALIBRATED IMAGES V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set set contains calibrated images of eight known transiting extrasolar planetary systems (hot Jupiters) acquired by the Deep Impact High Resolution...

  12. Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions: Overview of the Technology Maturation Efforts Funded by NASA's Game Changing Development Program

    Science.gov (United States)

    Beck, Robin A.; Arnold, James O.; Gasch, Matthew J.; Stackpoole, Margaret M.; Fan, Wendy; Szalai, Christine E.; Wercinski, Paul F.; Venkatapathy, Ethiraj

    2012-01-01

    The Office of Chief Technologist (OCT), NASA has identified the need for research and technology development in part from NASA's Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASA's exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program (GCDP) is a primary avenue to achieve the Agency's 2011 strategic goal to "Create the innovative new space technologies for our exploration, science, and economic future." In addition, recently released "NASA space Technology Roadmaps and Priorities," by the National Research Council (NRC) of the National Academy of Sciences stresses the need for NASA to invest in the very near term in specific EDL technologies. The report points out the following challenges (Page 2-38 of the pre-publication copy released on February 1, 2012): Mass to Surface: Develop the ability to deliver more payload to the destination. NASA's future missions will require ever-greater mass delivery capability in order to place scientifically significant instrument packages on distant bodies of interest, to facilitate sample returns from bodies of interest, and to enable human exploration of planets such as Mars. As the maximum mass that can be delivered to an entry interface is fixed for a given launch system and trajectory design, the mass delivered to the surface will require reduction in spacecraft structural mass; more efficient, lighter thermal protection systems; more efficient lighter propulsion systems; and lighter, more efficient deceleration systems. Surface Access: Increase the ability to land at a variety of planetary locales and at a variety of times. Access to specific sites can be achieved via landing at a specific location (s) or transit from a single designated landing location, but it is currently infeasible to transit long distances and through extremely rugged terrain, requiring landing close to the

  13. AN INCREASE IN THE MASS OF PLANETARY SYSTEMS AROUND LOWER-MASS STARS

    Energy Technology Data Exchange (ETDEWEB)

    Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel, E-mail: mulders@lpl.arizona.edu [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States)

    2015-12-01

    Trends in the planet population with host star mass provide an avenue to constrain planet formation theories. We derive the planet radius distribution function for Kepler stars of different spectral types, sampling a range in host star masses. We find that M dwarf stars have 3.5 times more small planets (1.0–2.8 R{sub ⨁}) than main-sequence FGK stars, but two times fewer Neptune-sized and larger (>2.8 R{sub ⨁}) planets. We find no systematic trend in the planet size distribution between spectral types F, G, and K to explain the increasing occurrence rates. Taking into account the mass–radius relationship and heavy-element mass of observed exoplanets, and assuming those are independent of spectral type, we derive the inventory of the heavy-element mass locked up in exoplanets at short orbits. The overall higher planet occurrence rates around M stars are not consistent with the redistribution of the same mass into more, smaller planets. At the orbital periods and planet radii where Kepler observations are complete for all spectral types, the average heavy-element mass locked up in exoplanets increases roughly inversely with stellar mass from 4 M{sub ⨁} in F stars to 5 M{sub ⨁} in G and K stars to 7 M{sub ⨁} in M stars. This trend stands in stark contrast with observed protoplanetary disk masses that decrease toward lower mass stars, and provides a challenge for current planet formation models. Neither models of in situ formation nor migration of fully formed planets are consistent with these results. Instead, these results are indicative of large-scale inward migration of planetary building blocks—either through type-I migration or radial drift of dust grains—that is more efficient for lower mass stars, but does not result in significantly larger or smaller planets.

  14. AN INCREASE IN THE MASS OF PLANETARY SYSTEMS AROUND LOWER-MASS STARS

    International Nuclear Information System (INIS)

    Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel

    2015-01-01

    Trends in the planet population with host star mass provide an avenue to constrain planet formation theories. We derive the planet radius distribution function for Kepler stars of different spectral types, sampling a range in host star masses. We find that M dwarf stars have 3.5 times more small planets (1.0–2.8 R ⨁ ) than main-sequence FGK stars, but two times fewer Neptune-sized and larger (>2.8 R ⨁ ) planets. We find no systematic trend in the planet size distribution between spectral types F, G, and K to explain the increasing occurrence rates. Taking into account the mass–radius relationship and heavy-element mass of observed exoplanets, and assuming those are independent of spectral type, we derive the inventory of the heavy-element mass locked up in exoplanets at short orbits. The overall higher planet occurrence rates around M stars are not consistent with the redistribution of the same mass into more, smaller planets. At the orbital periods and planet radii where Kepler observations are complete for all spectral types, the average heavy-element mass locked up in exoplanets increases roughly inversely with stellar mass from 4 M ⨁ in F stars to 5 M ⨁ in G and K stars to 7 M ⨁ in M stars. This trend stands in stark contrast with observed protoplanetary disk masses that decrease toward lower mass stars, and provides a challenge for current planet formation models. Neither models of in situ formation nor migration of fully formed planets are consistent with these results. Instead, these results are indicative of large-scale inward migration of planetary building blocks—either through type-I migration or radial drift of dust grains—that is more efficient for lower mass stars, but does not result in significantly larger or smaller planets

  15. Suppressed Far-UV Stellar Activity and Low Planetary Mass Loss in the WASP-18 System

    Science.gov (United States)

    Fossati, L.; Koskinen, T.; France, K.; Cubillos, P. E.; Haswell, C. A.; Lanza, A. F.; Pillitteri, I.

    2018-03-01

    WASP-18 hosts a massive, very close-in Jupiter-like planet. Despite its young age (extinction (E(B-V) ≈ 0.01 mag) and then the interstellar medium (ISM) column density for a number of ions, concluding that ISM absorption is not the origin of the anomaly. We measure the flux of the four stellar emission features detected in the COS spectrum (C II, C III, C IV, Si IV). Comparing the C II/C IV flux ratio measured for WASP-18 with that derived from spectra of nearby stars with known age, we see that the far-UV spectrum of WASP-18 resembles that of old (>5 Gyr), inactive stars, in stark contrast with its young age. We conclude that WASP-18 has an intrinsically low activity level, possibly caused by star–planet tidal interaction, as suggested by previous studies. Re-scaling the solar irradiance reference spectrum to match the flux of the Si IV line, yields an XUV integrated flux at the planet orbit of 10.2 erg s‑1 cm‑2. We employ the rescaled XUV solar fluxes to models of the planetary upper atmosphere, deriving an extremely low thermal mass-loss rate of 10‑20 M J Gyr‑1. For such high-mass planets, thermal escape is not energy limited, but driven by Jeans escape. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from MAST at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13859. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 092.D-0587.

  16. ANALYSIS OF THE POSSIBILITY OF INTEGRATING A MINING RIGHT-ANGLE PLANETARY GEARBOX WITH TECHNICAL DIAGNOSTICS SYSTEMS

    Directory of Open Access Journals (Sweden)

    Andrzej WIECZOREK

    2016-12-01

    Full Text Available A key factor enabling the achievement of the required capacity by longwall mining systems is to obtain a satisfactory service life for individual components of such systems. Such components include right-angle planetary gearboxes for armoured face conveyors. An increase in the service life of such equipment can be achieved by ensuring adequacy in terms of design, materials and organization. As a part of organizational changes, the use of individual diagnostics systems may have the greatest impact on the service life of mining gearboxes; however, their widespread implementation is limited by economic and operational barriers. This paper presents an analysis of the possibility of integrating mining gearboxes with electronic systems of technical diagnostics, as well as expanding the scope of the technical condition monitoring by the machines operating together with these gearboxes. As a result of the calculation and design work performed, it has been demonstrated that it is possible to integrate technical diagnostics systems with advanced data transmission capabilities inside gearboxes.

  17. Liquid-Liquid Phase Transition and Glass Transition in a Monoatomic Model System

    Directory of Open Access Journals (Sweden)

    Nicolas Giovambattista

    2010-12-01

    Full Text Available We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

  18. ngVLA Key Science Goal 2: Probing the Initial Conditions for Planetary Systems and Life with Astrochemistry

    Science.gov (United States)

    McGuire, Brett; ngVLA Science Working Group 1

    2018-01-01

    One of the most challenging aspects in understanding the origin and evolution of planets and planetary systems is tracing the influence of chemistry on the physical evolution of a system from a molecular cloud to a solar system. Existing facilities have already shown the stunning degree of molecular complexity present in these systems. The unique combination of sensitivity and spatial resolution offered by the ngVLA will permit the observation of both highly complex and very low-abundance chemical species that are exquisitely sensitive to the physical conditions and evolutionary history of their sources, which are out of reach of current observatories. In turn, by understanding the chemical evolution of these complex molecules, unprecedentedly detailed astrophysical insight can be gleaned from these astrochemical observations.This poster will overview a number of key science goals in astrochemistry which will be enabled by the ngVLA, including:1) imaging of the deepest, densest regions in protoplanetary disks and unveiling the physical history through isotopic ratios2) probing the ammonia snow line in these disks, thought to be the only viable tracer of the water snowline3) observations of the molecular content of giant planet atmospheres4) detections of new, complex molecules, potentially including the simplest amino acids and sugars5) tracing the origin of chiral excess in star-forming regions

  19. Kinematics of galactic planetary nebulae

    International Nuclear Information System (INIS)

    Kiosa, M.I.; Khromov, G.S.

    1979-01-01

    The classical method of determining the components of the solar motion relative to the centroid of the system of planetary nebulae with known radial velocities is investigated. It is shown that this method is insensitive to random errors in the radial velocities and that low accuracy in determining the coordinates of the solar apex and motion results from the insufficient number of planetaries with measured radial velocities. The planetary nebulae are found not to satisfy well the law of differential galactic rotation with circular orbits. This is attributed to the elongation of their galactic orbits. A method for obtaining the statistical parallax of planetary nebulae is considered, and the parallax calculated from the tau components of their proper motion is shown to be the most reliable

  20. Mars Technology Program Planetary Protection Technology Development

    Science.gov (United States)

    Lin, Ying

    2006-01-01

    The objectives of the NASA Planetary Protection program are to preserve biological and organic conditions of solar-system bodies for future scientific exploration and to protect the Earth from potential hazardous extraterrestrial contamination. As the exploration of solar system continues, NASA remains committed to the implementation of planetary protection policy and regulations. To fulfill this commitment, the Mars Technology Program (MTP) has invested in a portfolio of tasks for developing necessary technologies to meet planetary protection requirements for the next decade missions.

  1. Descriptions of Transit Maintenance Management Information Systems

    Science.gov (United States)

    1984-10-01

    This 289-page report presents an overview of ten maintenance management information systems that are currently operational or near-operational on minicomputers or microcomputers. The systems described address one or more of the following concerns: co...

  2. A rural transit asset management system

    Science.gov (United States)

    2005-01-01

    This reports the research undertaken to create an interactive, geographic information system based asset management system for the Alabama Department of Transportation to manage vehicles purchased and operated through Section 5310 and 5311 federal gr...

  3. Bisimulation and Open Maps for Timed Transition Systems

    DEFF Research Database (Denmark)

    Nielsen, Mogens

    1999-01-01

    Formal models for real-time systems have been studied intensively over the past decade. Much of the theory of untimed systems have been lifted to real-time settings. One example is the notion of bisimulation applied to timed transition systems, which is studied here within the general categorical...

  4. Solar System Exploration Augmented by In-Situ Resource Utilization: Human Planetary Base Issues for Mercury and Saturn

    Science.gov (United States)

    Palaszewski, Bryan A.

    2017-01-01

    Human and robotic missions to Mercury and Saturn are presented and analyzed with a range of propulsion options. Historical studies of space exploration, planetary spacecraft, and astronomy, in-situ resource utilization (ISRU), and industrialization all point to the vastness of natural resources in the solar system. Advanced propulsion benefitted from these resources in many ways. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal and nuclear pulse propulsion as well as advanced chemical propulsion can significantly enhance these scenarios. Updated analyses based on these historical visions are presented. Nuclear thermal propulsion and ISRU enhanced chemical propulsion landers are assessed for Mercury missions. At Saturn, nuclear pulse propulsion with alternate propellant feed systems and Saturn moon exploration with chemical propulsion and nuclear electric propulsion options are discussed. Issues with using in-situ resource utilization on Mercury missions are discussed. At Saturn, the best locations for exploration and the use of the moons Titan and Enceladus as central locations for Saturn moon exploration is assessed.

  5. Sustainability and deliberate transition of socio-technical systems

    DEFF Research Database (Denmark)

    Hansen, Ole Erik; Søndergård, Bent; Stærdahl, Jens

    or developing socio-technical systems in order to integrate the concept of sustainability as a driver for the deliberate and purposeful shaping and transition. The article discusses the requirements to effective governance networks and governing of governance networks. Research within innovation systems......The article suggests that deliberate planning for sustainability demands a focus on the transition of socio-technical systems in order to establish robust and more sustainable patterns of production and consumption. This implies the necessity of a new perspective for environmental planning......, transition management and technology systems combined with planning and experimental activities provides both a theoretical and empirical body of knowledge of such governance processes. The article discusses how this perspective can be used in relation to the process of developing bio-fuel systems...

  6. Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system

    Directory of Open Access Journals (Sweden)

    WorsØe Jonas

    2011-12-01

    Full Text Available Abstract Background Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. Methods A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4 giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, ϕ. Eight healthy subjects were each investigated three times: (1 with a small magnet mounted on a capsule endoscope (PillCam; (2 with the magnet alone and the small intestine in the fasting state; and (3 with the magnet alone and the small intestine in the postprandial state. Results Experiment (1 showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min and small intestinal transit time (median difference 0.5 min; range: 0-52 min. Comparing experiments (1 and (2 there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2 and (3, short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1 (p = 0.03. Conclusion MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

  7. FTA real-time transit information assessment : white paper on literature review of real-time transit information systems.

    Science.gov (United States)

    Real-time transit information systems are key technology applications within the transit industry designed to provide better customer service by disseminating timely and accurate information. Riders use this information to make various decisions abou...

  8. Business strategies for transitions to sustainable systems

    NARCIS (Netherlands)

    D.A. Loorbach (Derk); J.C. Bakel (Janneke); G.M. Whiteman (Gail); J. Rotmans (Jan)

    2010-01-01

    textabstractThis paper develops a strategic perspective for business to contribute to the innovation of societal systems. Sustainability issues at the level of societal sectors cannot be addressed by single organizations but need to be thought of as systemic challenges in which business, government

  9. Stochastic hybrid systems with renewal transitions

    NARCIS (Netherlands)

    Guerreiro Tome Antunes, D.J.; Hespanha, J.P.; Silvestre, C.J.

    2010-01-01

    We consider Stochastic Hybrid Systems (SHSs) for which the lengths of times that the system stays in each mode are independent random variables with given distributions. We propose an analysis framework based on a set of Volterra renewal-type equations, which allows us to compute any statistical

  10. Autonomous Trans-Antartic expeditions: an initiative for advancing planetary mobility system technology while addressing Earth science objectives in Antartica

    Science.gov (United States)

    Carsey, F.; Schenker, P.; Blamont, J.

    2001-01-01

    A workshop on Antartic Autonomous Scientific Vehicles and Traverses met at the National Geographic Society in February to discuss scientific objectives and benefits of the use of rovers such as are being developed for use in planetary exploration.

  11. Topology of sustainable management of dynamical systems with desirable states: from defining planetary boundaries to safe operating spaces in the Earth System

    Science.gov (United States)

    Heitzig, Jobst; Kittel, Tim; Donges, Jonathan; Molkenthin, Nora

    2016-04-01

    To keep the Earth System in a desirable region of its state space, such as defined by the recently suggested "tolerable environment and development window", "guardrails", "planetary boundaries", or "safe (and just) operating space for humanity", one not only needs to understand the quantitative internal dynamics of the system and the available options for influencing it (management), but also the structure of the system's state space with regard to certain qualitative differences. Important questions are: Which state space regions can be reached from which others with or without leaving the desirable region? Which regions are in a variety of senses "safe" to stay in when management options might break away, and which qualitative decision problems may occur as a consequence of this topological structure? In this work, we develop a mathematical theory of the qualitative topology of the state space of a dynamical system with management options and desirable states, as a complement to the existing literature on optimal control which is more focussed on quantitative optimization and is much applied in both the engineering and the integrated assessment literature. We suggest a certain terminology for the various resulting regions of the state space and perform a detailed formal classification of the possible states with respect to the possibility of avoiding or leaving the undesired region. Our results indicate that before performing some form of quantitative optimization such as of indicators of human well-being for achieving certain sustainable development goals, a sustainable and resilient management of the Earth System may require decisions of a more discrete type that come in the form of several dilemmas, e.g., choosing between eventual safety and uninterrupted desirability, or between uninterrupted safety and larger flexibility. We illustrate the concepts and dilemmas drawing on conceptual models from climate science, ecology, coevolutionary Earth System modeling

  12. Nervous System Injury in Response to Contact With Environmental, Engineered and Planetary Micro- and Nano-Sized Particles

    Directory of Open Access Journals (Sweden)

    Tatiana Borisova

    2018-06-01

    Full Text Available Nerve cells take a special place among other cells in organisms because of their unique function mechanism. The plasma membrane of nerve cells from the one hand performs a classical barrier function, thereby being foremost targeted during contact with micro- and nano-sized particles, and from the other hand it is very intensively involved in nerve signal transmission, i.e., depolarization-induced calcium-dependent compound exocytosis realized via vesicle fusion following by their retrieval and calcium-independent permanent neurotransmitter turnover via plasma membrane neurotransmitter transporters that utilize Na+/K+ electrochemical gradient as a driving force. Worldwide traveling air pollution particulate matter is now considered as a possible trigger factor for the development of a variety of neuropathologies. Micro- and nano-sized particles can reach the central nervous system during inhalation avoiding the blood–brain barrier, thereby making synaptic neurotransmission extremely sensitive to their influence. Neurosafety of environmental, engineered and planetary particles is difficult to predict because they possess other features as compared to bulk materials from which the particles are composed of. The capability of the particles to absorb heavy metals and organic neurotoxic molecules from the environment, and moreover, spontaneously interact with proteins and lipids in organisms and form biomolecular corona can considerably change the particles‘ features. The absorption capability occasionally makes them worldwide traveling particulate carriers for delivery of environmental neurotoxic compounds to the brain. Discrepancy of the experimental data on neurotoxicity assessment of micro- and nano-sized particles can be associated with a variability of systems, in which neurotoxicity was analyzed and where protein components of the incubation media forming particle biocorona can significantly distort and even eliminate factual particle

  13. Constraining the Movement of the Spiral Features and the Locations of Planetary Bodies Within the AB Aur System

    Science.gov (United States)

    Lomax, Jamie R.; Wisniewski, John P.; Grady, Carol A.; McElwain, Michael W.; Hashimoto, Jun; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Okamoto, Yoshiko K.; Fukagawa, Misato; Abe, Lyu

    2016-01-01

    We present a new analysis of multi-epoch, H-band, scattered light images of the AB Aur system. We use a Monte Carlo radiative transfer code to simultaneously model the systems spectral energy distribution (SED) and H-band polarized intensity (PI) imagery. We find that a disk-dominated model, as opposed to one that is envelope dominated, can plausibly reproduce AB Aurs SED and near-IR imagery. This is consistent with previous modeling attempts presented in the literature and supports the idea that at least a subset of AB Aurs spirals originate within the disk. In light of this, we also analyzed the movement of spiral structures in multi-epoch H-band total light and PI imagery of the disk. We detect no significant rotation or change in spatial location of the spiral structures in these data, which span a 5.8-year baseline. If such structures are caused by disk planet interactions, the lack of observed rotation constrains the location of the orbit of planetary perturbers to be 47 au.

  14. Information systems in logistics - transition challenges

    Directory of Open Access Journals (Sweden)

    Nikolay Dragomirov

    2016-03-01

    Full Text Available The implementation of information systems in business organizations does not consist of just buying software products and installing them on the servers. Most of these systems are important for the development of the organizations concerned and in some cases are very expensive. Therefore, their success requires a properly managed process of implementation, which seeks a balance between the aims of the systems and the financial and technical capabilities of the organization. The implementation problem becomes greater when the emphasis is on the logistics function in the context of the supply chain management. Last, but not least, these initiatives are related to something much more challenging, namely the adoption of the new information system by the users, which involves a change of habits in the organization. It is no secret that a new system may be rejected by its users and this will make it useless. All this requires finding adequate solutions to analyze these problems and to ensure the effective use of information systems in logistics.

  15. MARVELS-1: A FACE-ON DOUBLE-LINED BINARY STAR MASQUERADING AS A RESONANT PLANETARY SYSTEM AND CONSIDERATION OF RARE FALSE POSITIVES IN RADIAL VELOCITY PLANET SEARCHES

    International Nuclear Information System (INIS)

    Wright, Jason T.; Roy, Arpita; Mahadevan, Suvrath; Wang, Sharon X.; Fleming, Scott W.; Ford, Eric B.; Payne, Matt; Lee, Brian L.; Ge, Jian; Wang, Ji; Crepp, Justin R.; Gaudi, B. Scott; Eastman, Jason; Pepper, Joshua; Cargile, Phillip; Stassun, Keivan G.; Ghezzi, Luan; González-Hernández, Jonay I.; Wisniewski, John; Dutra-Ferreira, Leticia

    2013-01-01

    We have analyzed new and previously published radial velocity (RV) observations of MARVELS-1, known to have an ostensibly substellar companion in a ∼6 day orbit. We find significant (∼100 m s –1 ) residuals to the best-fit model for the companion, and these residuals are naïvely consistent with an interior giant planet with a P = 1.965 days in a nearly perfect 3:1 period commensurability (|P b /P c – 3| –4 ). We have performed several tests for the reality of such a companion, including a dynamical analysis, a search for photometric variability, and a hunt for contaminating stellar spectra. We find many reasons to be critical of a planetary interpretation, including the fact that most of the three-body dynamical solutions are unstable. We find no evidence for transits, and no evidence of stellar photometric variability. We have discovered two apparent companions to MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-alarm scenarios inspired by various curiosities in the data. Ultimately, a line profile and bisector analysis lead us to conclude that the ∼100 m s –1 residuals are an artifact of spectral contamination from a stellar companion contributing ∼15%-30% of the optical light in the system. We conclude that origin of this contamination is the previously detected RV companion to MARVELS-1, which is not, as previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.

  16. SOAP-T: a tool to study the light curve and radial velocity of a system with a transiting planet and a rotating spotted star

    Science.gov (United States)

    Oshagh, M.; Boisse, I.; Boué, G.; Montalto, M.; Santos, N. C.; Bonfils, X.; Haghighipour, N.

    2013-01-01

    We present an improved version of SOAP named "SOAP-T", which can generate the radial velocity variations and light curves for systems consisting of a rotating spotted star with a transiting planet. This tool can be used to study the anomalies inside transit light curves and the Rossiter-McLaughlin effect, to better constrain the orbital configuration and properties of planetary systems and the active zones of their host stars. Tests of the code are presented to illustrate its performance and to validate its capability when compared with analytical models and real data. Finally, we apply SOAP-T to the active star, HAT-P-11, observed by the NASA Kepler space telescope and use this system to discuss the capability of this tool in analyzing light curves for the cases where the transiting planet overlaps with the star's spots. The tool's public interface is available at http://www.astro.up.pt/resources/soap-t/

  17. Exponential law as a more compatible model to describe orbits of planetary systems

    Directory of Open Access Journals (Sweden)

    M Saeedi

    2012-12-01

    Full Text Available   According to the Titus-Bode law, orbits of planets in the solar system obey a geometric progression. Many investigations have been launched to improve this law. In this paper, we apply square and exponential models to planets of solar system, moons of planets, and some extra solar systems, and compare them with each other.

  18. Transition Manifolds of Complex Metastable Systems

    Science.gov (United States)

    Bittracher, Andreas; Koltai, Péter; Klus, Stefan; Banisch, Ralf; Dellnitz, Michael; Schütte, Christof

    2018-04-01

    We consider complex dynamical systems showing metastable behavior, but no local separation of fast and slow time scales. The article raises the question of whether such systems exhibit a low-dimensional manifold supporting its effective dynamics. For answering this question, we aim at finding nonlinear coordinates, called reaction coordinates, such that the projection of the dynamics onto these coordinates preserves the dominant time scales of the dynamics. We show that, based on a specific reducibility property, the existence of good low-dimensional reaction coordinates preserving the dominant time scales is guaranteed. Based on this theoretical framework, we develop and test a novel numerical approach for computing good reaction coordinates. The proposed algorithmic approach is fully local and thus not prone to the curse of dimension with respect to the state space of the dynamics. Hence, it is a promising method for data-based model reduction of complex dynamical systems such as molecular dynamics.

  19. An assessment method for system innovation and transition (AMSIT)

    NARCIS (Netherlands)

    Bos, Marc W.; Hofman, Erwin; Kuhlmann, Stefan

    2016-01-01

    To address comprehensive system innovations that may occur in a future transition, a suitable ex ante assessment method is required. The technological innovation system approach is useful for the retrospective study of the conditions for success or failure of innovation trajectories, and the

  20. Robotic vehicles for planetary exploration

    Science.gov (United States)

    Wilcox, Brian; Matthies, Larry; Gennery, Donald; Cooper, Brian; Nguyen, Tam; Litwin, Todd; Mishkin, Andrew; Stone, Henry

    1992-01-01

    A program to develop planetary rover technology is underway at the Jet Propulsion Laboratory (JPL) under sponsorship of the National Aeronautics and Space Administration. Developmental systems with the necessary sensing, computing, power, and mobility resources to demonstrate realistic forms of control for various missions have been developed, and initial testing has been completed. These testbed systems and the associated navigation techniques used are described. Particular emphasis is placed on three technologies: Computer-Aided Remote Driving (CARD), Semiautonomous Navigation (SAN), and behavior control. It is concluded that, through the development and evaluation of such technologies, research at JPL has expanded the set of viable planetary rover mission possibilities beyond the limits of remotely teleoperated systems such as Lunakhod. These are potentially applicable to exploration of all the solid planetary surfaces in the solar system, including Mars, Venus, and the moons of the gas giant planets.

  1. Divergent Quiescent Transition Systems (extended version)

    NARCIS (Netherlands)

    Stokkink, W.G.J.; Timmer, Mark; Stoelinga, Mariëlle Ida Antoinette

    Quiescence is a fundamental concept in modelling system behaviour, as it explicitly represents the fact that no output is produced in certain states. The notion of quiescence is also essential to model-based testing: if a particular implementation under test does not provide any output, then the

  2. SOPHIE velocimetry of Kepler transit candidates: a joint photometric, spectroscopic and dynamical analysis of the Kepler-117 system

    Directory of Open Access Journals (Sweden)

    Bruno G.

    2015-01-01

    Full Text Available We present the analysis of the multi-planetary system Kepler-117, which is part of our program of observations of Kepler planets. This system is composed of a ~ 30 MEarth planet in a ~ 19 days orbit and a ~ 2 MJ planet orbiting in ~ 51 days. Both the orbits have low eccentricity. The planets are not close to an exact low-order mean motion resonance, but exhibit significant transit timing variations (TTVs nevertheless. We perform a combined Markov Chain Monte Carlo fit on all the available data: the Kepler photometry, the TTVs, the radial velocities we obtained with SOPHIE/OHP and the stellar parameters. The prime result is that the modelling of the TTVs allows to increase the precision on the system parameters which are not constrained by the radial velocities alone.

  3. Lunar and Planetary Science XXXV: Special Session: Oxygen in the Solar System, I

    Science.gov (United States)

    2004-01-01

    The Special Session: Oxygen in the Solar System, I, included the following reports:Oxygen in the Solar System: Origins of Isotopic and Redox Complexity; The Origin of Oxygen Isotope Variations in the Early Solar System; Solar and Solar-Wind Oxygen Isotopes and the Genesis Mission; Solar 18O/17O and the Setting for Solar Birth; Oxygen Isotopes in Early Solar System Materials: A Perspective Based on Microbeam Analyses of Chondrules from CV Carbonaceous Chondrites; Insight into Primordial Solar System Oxygen Reservoirs from Returned Cometary Samples; Tracing Meteorites to Their Sources Through Asteroid Spectroscopy; Redox Conditions Among the Terrestrial Planets; Redox Complexity in Martian Meteorites: Implications for Oxygen in the Terrestrial Planets; Implications of Sulfur Isotopes for the Evolution of Atmospheric Oxygen; Oxygen in the Outer Solar System; and On the Oxidation States of the Galilean Satellites: Implications for Internal Structures.

  4. Dissipation-driven quantum phase transitions in collective spin systems

    International Nuclear Information System (INIS)

    Morrison, S; Parkins, A S

    2008-01-01

    We consider two different collective spin systems subjected to strong dissipation-on the same scale as interaction strengths and external fields-and show that either continuous or discontinuous dissipative quantum phase transitions can occur as the dissipation strength is varied. First, we consider a well-known model of cooperative resonance fluorescence that can exhibit a second-order quantum phase transition, and analyse the entanglement properties near the critical point. Next, we examine a dissipative version of the Lipkin-Meshkov-Glick interacting collective spin model, where we find that either first- or second-order quantum phase transitions can occur, depending only on the ratio of the interaction and external field parameters. We give detailed results and interpretation for the steady-state entanglement in the vicinity of the critical point, where it reaches a maximum. For the first-order transition we find that the semiclassical steady states exhibit a region of bistability. (fast track communication)

  5. Transitioning to Biofuels: A System-of-Systems Perspective; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Riley, C.; Sandor, D.

    2008-06-01

    Using the existing fuel supply chain infrastructure as a framework, this paper discusses a vision for transitioning to a larger biofuels industry and the challenges associated with a massive market and infrastructure transformation.

  6. Esophageal transit scintigraphy in systemic sclerosis

    Directory of Open Access Journals (Sweden)

    Marek Chojnowski

    2016-11-01

    Full Text Available Systemic sclerosis is a rare connective tissue disease, distinctive features of which are fibrosis and microangiopathy. The esophagus is one of the most commonly involved internal organs. Most patients experience dysphagia, difficulties in swallowing and gastro-esophageal reflux. However, in up to one third of cases, the initial onset of esophageal disease may be clinically silent. There are several diagnostic modalities available for assessing both morphological and functional abnormalities of the esophagus. If structural abnormalities are suspected, endoscopy is the method of choice. Functional evaluation is best achieved with manometry. Both endoscopy and manometry are invasive techniques, with low patient acceptance. Barium-contrast study is well tolerated, but qualitative assessment of functional abnormalities is imprecise. Esophageal scintigraphy is an easy, non-invasive, sensitive and specific diagnostic modality. It can detect esophageal dysfunction even in asymptomatic patients. In patients already diagnosed with systemic sclerosis, scintigraphy is useful in evaluating severity and progression of the disease.

  7. Dimensionality and integrals of motion of the Trappist-1 planetary system

    Science.gov (United States)

    Floß, Johannes; Rein, Hanno; Brumer, Paul

    2018-04-01

    The number of isolating integrals of motion of the Trappist-1 system - a late M-dwarf orbited by seven Earth-sized planets - was determined numerically, using an adapted version of the correlation dimension method. It was found that over the investigated time-scales of up to 20 000 years the number of isolating integrals of motion is the same as one would find for a system of seven non-interacting planets - despite the fact that the planets in the Trappist-1 system are strongly interacting. Considering perturbed versions of the Trappist-1 system shows that the system may occupy an atypical part of phase-space with high stability. These findings are consistent with earlier studies.

  8. Exploring the Solar System Activities Outline: Hands-On Planetary Science for Formal Education K-14 and Informal Settings

    Science.gov (United States)

    Allen, J. S.; Tobola, K. W.; Lindstrom, M. L.

    2003-01-01

    Activities by NASA scientists and teachers focus on integrating Planetary Science activities with existing Earth science, math, and language arts curriculum. The wealth of activities that highlight missions and research pertaining to the exploring the solar system allows educators to choose activities that fit a particular concept or theme within their curriculum. Most of the activities use simple, inexpensive techniques that help students understand the how and why of what scientists are learning about comets, asteroids, meteorites, moons and planets. With these NASA developed activities students experience recent mission information about our solar system such as Mars geology and the search for life using Mars meteorites and robotic data. The Johnson Space Center ARES Education team has compiled a variety of NASA solar system activities to produce an annotated thematic outline useful to classroom educators and informal educators as they teach space science. An important aspect of the outline annotation is that it highlights appropriate science content information and key science and math concepts so educators can easily identify activities that will enhance curriculum development. The outline contains URLs for the activities and NASA educator guides as well as links to NASA mission science and technology. In the informal setting educators can use solar system exploration activities to reinforce learning in association with thematic displays, planetarium programs, youth group gatherings, or community events. Within formal education at the primary level some of the activities are appropriately designed to excite interest and arouse curiosity. Middle school educators will find activities that enhance thematic science and encourage students to think about the scientific process of investigation. Some of the activities offered are appropriate for the upper levels of high school and early college in that they require students to use and analyze data.

  9. CONSTRAINING THE MOVEMENT OF THE SPIRAL FEATURES AND THE LOCATIONS OF PLANETARY BODIES WITHIN THE AB AUR SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Lomax, Jamie R.; Wisniewski, John P.; Hashimoto, Jun [Homer L. Dodge Department of Physics, University of Oklahoma, Norman, OK 73071 (United States); Grady, Carol A. [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McElwain, Michael W. [NASA Goddard Space Flight Center, Code 6681, Greenbelt, MD 20771 (United States); Kudo, Tomoyuki; Currie, Thayne M; Egner, Sebastian; Guyon, Olivier; Hayano, Yutaka [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720 (United States); Kusakabe, Nobuhiko; Hayashi, Masahiko [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Okamoto, Yoshiko K. [Institute of Astrophysics and Planetary Sciences, Faculty of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Fukagawa, Misato [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Abe, Lyu [Laboratoire Lagrange (UMR 7293), Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d’Azur, 28 avenue Valrose, F-06108 Nice Cedex 2 (France); Brandner, Wolfgang; Feldt, Markus [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Brandt, Timothy D. [Astrophysics Department, Institute for Advanced Study, Princeton, NJ 08540 (United States); Carson, Joseph C. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); Goto, Miwa, E-mail: Jamie.R.Lomax@ou.edu, E-mail: wisniewski@ou.edu, E-mail: carol.a.grady@nasa.gov [Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 München (Germany); and others

    2016-09-01

    We present a new analysis of multi-epoch, H -band, scattered light images of the AB Aur system. We use a Monte Carlo radiative transfer code to simultaneously model the system’s spectral energy distribution (SED) and H -band polarized intensity (PI) imagery. We find that a disk-dominated model, as opposed to one that is envelope-dominated, can plausibly reproduce AB Aur’s SED and near-IR imagery. This is consistent with previous modeling attempts presented in the literature and supports the idea that at least a subset of AB Aur’s spirals originate within the disk. In light of this, we also analyzed the movement of spiral structures in multi-epoch H -band total light and PI imagery of the disk. We detect no significant rotation or change in spatial location of the spiral structures in these data, which span a 5.8-year baseline. If such structures are caused by disk–planet interactions, the lack of observed rotation constrains the location of the orbit of planetary perturbers to be >47 au.

  10. Constraint on Additional Planets in Planetary Systems Discovered Through the Channel of High-magnification Gravitational Microlensing Events

    Science.gov (United States)

    Shin, I.-G.; Han, C.; Choi, J.-Y.; Hwang, K.-H.; Jung, Y.-K.; Park, H.

    2015-04-01

    High-magnification gravitational microlensing events provide an important channel of detecting planetary systems with multiple giants located at their birth places. In order to investigate the potential existence of additional planets, we reanalyze the light curves of the eight high-magnification microlensing events, for each of which a single planet was previously detected. The analyzed events include OGLE-2005-BLG-071, OGLE-2005-BLG-169, MOA-2007-BLG-400, MOA-2008-BLG-310, MOA-2009-BLG-319, MOA-2009-BLG-387, MOA-2010-BLG-477, and MOA-2011-BLG-293. We find that including an additional planet improves fits with {Δ }{{χ }2}\\lt 80 for seven out of eight analyzed events. For MOA-2009-BLG-319, the improvement is relatively big with {Δ }{{χ }2}∼ 143. From inspection of the fits, we find that the improvement of the fits is attributed to systematics in data. Although no clear evidence of additional planets is found, it is still possible to constrain the existence of additional planets in the parameter space. For this purpose, we construct exclusion diagrams showing the confidence levels excluding the existence of an additional planet as a function of its separation and mass ratio. We also present the exclusion ranges of additional planets with 90% confidence level for Jupiter-, Saturn-, and Uranus-mass planets.

  11. System Integration and Interface Transition Issues.

    Science.gov (United States)

    1977-04-01

    OC - 4- u -O m4 U V L.- I~V 0~ C 0 - i CC 0 .iOC30~i .- ~. C > u uU O! ul Wi 0) i~ LUn CL04) z w 0 CL-0r I.- ~ ~~~~ in0 6 - 2-A 0 ~ 4) 0 zEC u~5. 0...Systems Design and Documentation - An Introduction to the HIPO Method, Van Nostrand Reinhold Co. (1976). [34] Peter Freeman, "Toward Improved Review of...Software Design," Proc. National Computer Conf. 44, AFIPS Press (1975) pp 329-334. [35] Peter G. Neumann, "Software Development & Proofs of Multi-Level

  12. VARIATIONAL PRINCIPLE FOR PLANETARY INTERIORS

    International Nuclear Information System (INIS)

    Zeng, Li; Jacobsen, Stein B.

    2016-01-01

    In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. The variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory, which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying the variational principle to the planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From this principle, a universal mass–radius relation, an estimate of the error propagation from the equation of state to the mass–radius relation, and a form of the virial theorem applicable to planetary interiors are derived.

  13. Electrostatic Phenomena on Planetary Surfaces

    Science.gov (United States)

    Calle, Carlos I.

    2017-02-01

    The diverse planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near planetary surfaces. The desire to understand the electrostatic environments of planetary surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.

  14. Planetary Geologic Mapping Handbook - 2009

    Science.gov (United States)

    Tanaka, K. L.; Skinner, J. A.; Hare, T. M.

    2009-01-01

    . Terrestrial geologic maps published by the USGS now are primarily digital products using geographic information system (GIS) software and file formats. GIS mapping tools permit easy spatial comparison, generation, importation, manipulation, and analysis of multiple raster image, gridded, and vector data sets. GIS software has also permitted the development of project-specific tools and the sharing of geospatial products among researchers. GIS approaches are now being used in planetary geologic mapping as well (e.g., Hare and others, 2009). Guidelines or handbooks on techniques in planetary geologic mapping have been developed periodically (e.g., Wilhelms, 1972, 1990; Tanaka and others, 1994). As records of the heritage of mapping methods and data, these remain extremely useful guides. However, many of the fundamental aspects of earlier mapping handbooks have evolved significantly, and a comprehensive review of currently accepted mapping methodologies is now warranted. As documented in this handbook, such a review incorporates additional guidelines developed in recent years for planetary geologic mapping by the NASA Planetary Geology and Geophysics (PGG) Program s Planetary Cartography and Geologic Mapping Working Group s (PCGMWG) Geologic Mapping Subcommittee (GEMS) on the selection and use of map bases as well as map preparation, review, publication, and distribution. In light of the current boom in planetary exploration and the ongoing rapid evolution of available data for planetary mapping, this handbook is especially timely.

  15. Autonomous Soil Assessment System: A Data-Driven Approach to Planetary Mobility Hazard Detection

    Science.gov (United States)

    Raimalwala, K.; Faragalli, M.; Reid, E.

    2018-04-01

    The Autonomous Soil Assessment System predicts mobility hazards for rovers. Its development and performance are presented, with focus on its data-driven models, machine learning algorithms, and real-time sensor data fusion for predictive analytics.

  16. Planetary protection issues related to human missions to Mars

    Science.gov (United States)

    Debus, A.; Arnould, J.

    2008-09-01

    In accordance with the United Nations Outer Space Treaties [United Nations, Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, UN doc A/RES/34/68, resolution 38/68 of December 1979], currently maintained and promulgated by the Committee on Space Research [COSPAR Planetary Protection Panel, Planetary Protection Policy accepted by the COSPAR Council and Bureau, 20 October 2002, amended 24 March 2005, http://www.cosparhq.org/scistr/PPPolicy.htm], missions exploring the Solar system must meet planetary protection requirements. Planetary protection aims to protect celestial bodies from terrestrial contamination and to protect the Earth environment from potential biological contamination carried by returned samples or space systems that have been in contact with an extraterrestrial environment. From an exobiology perspective, Mars is one of the major targets, and several missions are currently in operation, in transit, or scheduled for its exploration. Some of them include payloads dedicated to the detection of life or traces of life. The next step, over the coming years, will be to return samples from Mars to Earth, with a view to increasing our knowledge in preparation for the first manned mission that is likely to take place within the next few decades. Robotic missions to Mars shall meet planetary protection specifications, currently well documented, and planetary protection programs are implemented in a very reliable manner given that experience in the field spans some 40 years. With regards to sample return missions, a set of stringent requirements has been approved by COSPAR [COSPAR Planetary Protection Panel, Planetary Protection Policy accepted by the COSPAR Council and Bureau, 20 October 2002, amended 24 March 2005, http://www.cosparhq.org/scistr/PPPolicy.htm], and technical challenges must now be overcome in order to preserve the Earth’s biosphere from any eventual contamination risk. In addition to the human dimension of

  17. Phase transition universality classes of classical, nonequilibrium systems

    CERN Document Server

    Ódor, G

    2004-01-01

    In the first chapter I summarize the most important critical exponents and relations used in this work. In the second chapter I briefly address the question of scaling behavior at first order phase transitions.In chapter three I review dynamical extensions of basic static classes, show the effect of mixing dynamics and percolation behavior. The main body of this work is given in chapter four where genuine, dynamical universality classes specific to nonequilibrium systems are introduced. In chapter five I continue overviewing such nonequilibrium classes but in coupled, multi-component systems. Most of known transitions in low dimensional systems are between active and absorbing states of reaction-diffusion type systems, but I briefly introduce related classes that appear in interface growth models in chapter six. Some of them are related to critical behavior of coupled, multi-component systems. Finally in chapter seven I summarize families of absorbing state system classes, mean-field classes and the most freq...

  18. The Goldstone solar system radar: A science instrument for planetary research

    Science.gov (United States)

    Dvorsky, J. D.; Renzetti, N. A.; Fulton, D. E.

    1992-01-01

    The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided.

  19. Robotic Planetary Drill Tests

    Science.gov (United States)

    Glass, Brian J.; Thompson, S.; Paulsen, G.

    2010-01-01

    Several proposed or planned planetary science missions to Mars and other Solar System bodies over the next decade require subsurface access by drilling. This paper discusses the problems of remote robotic drilling, an automation and control architecture based loosely on observed human behaviors in drilling on Earth, and an overview of robotic drilling field test results using this architecture since 2005. Both rotary-drag and rotary-percussive drills are targeted. A hybrid diagnostic approach incorporates heuristics, model-based reasoning and vibration monitoring with neural nets. Ongoing work leads to flight-ready drilling software.

  20. Planetary submillimeter spectroscopy

    Science.gov (United States)

    Klein, M. J.

    1988-01-01

    The aim is to develop a comprehensive observational and analytical program to study solar system physics and meterology by measuring molecular lines in the millimeter and submillimeter spectra of planets and comets. A primary objective is to conduct observations with new JPL and Caltech submillimeter receivers at the Caltech Submillimeter Observatory (CSO) on Mauna Kea, Hawaii. A secondary objective is to continue to monitor the time variable planetary phenomena (e.g., Jupiter and Uranus) at centimeter wavelength using the NASA antennas of the Deep Space Network (DSN).

  1. Mathematical models of non-linear phenomena, processes and systems: from molecular scale to planetary atmosphere

    CERN Document Server

    2013-01-01

    This book consists of twenty seven chapters, which can be divided into three large categories: articles with the focus on the mathematical treatment of non-linear problems, including the methodologies, algorithms and properties of analytical and numerical solutions to particular non-linear problems; theoretical and computational studies dedicated to the physics and chemistry of non-linear micro-and nano-scale systems, including molecular clusters, nano-particles and nano-composites; and, papers focused on non-linear processes in medico-biological systems, including mathematical models of ferments, amino acids, blood fluids and polynucleic chains.

  2. Analysis of developed transition road safety barrier systems.

    Science.gov (United States)

    Soltani, Mehrtash; Moghaddam, Taher Baghaee; Karim, Mohamed Rehan; Sulong, N H Ramli

    2013-10-01

    Road safety barriers protect vehicles from roadside hazards by redirecting errant vehicles in a safe manner as well as providing high levels of safety during and after impact. This paper focused on transition safety barrier systems which were located at the point of attachment between a bridge and roadside barriers. The aim of this study was to provide an overview of the behavior of transition systems located at upstream bridge rail with different designs and performance levels. Design factors such as occupant risk and vehicle trajectory for different systems were collected and compared. To achieve this aim a comprehensive database was developed using previous studies. The comparison showed that Test 3-21, which is conducted by impacting a pickup truck with speed of 100 km/h and angle of 25° to transition system, was the most severe test. Occupant impact velocity and ridedown acceleration for heavy vehicles were lower than the amounts for passenger cars and pickup trucks, and in most cases higher occupant lateral impact ridedown acceleration was observed on vehicles subjected to higher levels of damage. The best transition system was selected to give optimum performance which reduced occupant risk factors using the similar crashes in accordance with Test 3-21. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Asteroseismic inference on rotation, gyrochronology and planetary system dynamics of 16 Cygni

    DEFF Research Database (Denmark)

    Davies, G. R.; Chaplin, W. J.; Farr, W. M.

    2014-01-01

    The solar analogs 16 Cyg A and 16 Cyg B are excellent asteroseismic targets in the \\Kepler field of view and together with a red dwarf and a Jovian planet form an interesting system. For these more evolved Sun-like stars we cannot detect surface rotation with the current \\Kepler data but instead...

  4. STEM Engagement with NASA's Solar System Treks Portals for Lunar and Planetary Mapping and Modeling

    Science.gov (United States)

    Law, E. S.; Day, B. H.

    2018-01-01

    This presentation will provide an overview of the uses and capabilities of NASA's Solar System Treks family of online mapping and modeling portals. While also designed to support mission planning and scientific research, this presentation will focus on the Science, Technology, Engineering, and Math (STEM) engagement and public outreach capabilities of these web based suites of data visualization and analysis tools.

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

    CERN Document Server

    Beutler, Gerhard

    2005-01-01

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

  6. Climate, ecosystems, and planetary futures: The challenge to predict life in Earth system models.

    Science.gov (United States)

    Bonan, Gordon B; Doney, Scott C

    2018-02-02

    Many global change stresses on terrestrial and marine ecosystems affect not only ecosystem services that are essential to humankind, but also the trajectory of future climate by altering energy and mass exchanges with the atmosphere. Earth system models, which simulate terrestrial and marine ecosystems and biogeochemical cycles, offer a common framework for ecological research related to climate processes; analyses of vulnerability, impacts, and adaptation; and climate change mitigation. They provide an opportunity to move beyond physical descriptors of atmospheric and oceanic states to societally relevant quantities such as wildfire risk, habitat loss, water availability, and crop, fishery, and timber yields. To achieve this, the science of climate prediction must be extended to a more multifaceted Earth system prediction that includes the biosphere and its resources. Copyright © 2018, American Association for the Advancement of Science.

  7. Pulsed neutron generator system for astrobiological and geochemical exploration of planetary bodies

    International Nuclear Information System (INIS)

    Akkurt, Hatice; Groves, Joel L.; Trombka, Jacob; Starr, Richard; Evans, Larry; Floyd, Samuel; Hoover, Richard; Lim, Lucy; McClanahan, Timothy; James, Ralph; McCoy, Timothy; Schweitzer, Jeffrey

    2005-01-01

    A pulsed neutron/gamma-ray detection system for use on rovers to survey the elemental concentrations of Martian and Lunar surface and subsurface materials is evaluated. A robotic survey system combining a pulsed neutron generator (PNG) and detectors (gamma ray and neutron) can measure the major constituents to a depth of about 30 cm. Scanning mode measurements can give the major elemental concentrations while the rover is moving; analyzing mode measurements can give a detailed elemental analysis of the adjacent material when the rover is stationary. A detailed map of the subsurface elemental concentrations will provide invaluable information relevant to some of the most fundamental astrobiological questions including the presence of water, biogenic activity, life habitability and deposition processes

  8. Shear-induced transitions in a ternary polymeric system

    NARCIS (Netherlands)

    Zvelindovsky, AV; Sevink, GJA; Fraaije, JGEM

    The first three-dimensional simulation of shear-induced phase transitions in a polymeric system has been performed. The method is based on dynamic density-functional theory. The pathways between a bicontinuous phase with developing gyroid mesostructure and a lamellar/cylinder phase coexistence are

  9. Transition to Postgraduate Study: Postgraduate Ecological Systems and Identity

    Science.gov (United States)

    Tobbell, Jane; O'Donnell, Victoria L.

    2013-01-01

    This paper explores and examines the distal and proximal systems which construct social science postgraduate study in the UK and analyses the emergent identities of postgraduate students as they negotiate the multiple and interacting practices in their transition to study. The data represent part of a one-year research project, funded by the…

  10. Lunar and Planetary Geology

    Science.gov (United States)

    Basilevsky, Alexander T.

    2018-05-01

    Lunar and planetary geology can be described using examples such as the geology of Earth (as the reference case) and geologies of the Earth's satellite the Moon; the planets Mercury, Mars and Venus; the satellite of Saturn Enceladus; the small stony asteroid Eros; and the nucleus of the comet 67P Churyumov-Gerasimenko. Each body considered is illustrated by its global view, with information given as to its position in the solar system, size, surface, environment including gravity acceleration and properties of its atmosphere if it is present, typical landforms and processes forming them, materials composing these landforms, information on internal structure of the body, stages of its geologic evolution in the form of stratigraphic scale, and estimates of the absolute ages of the stratigraphic units. Information about one body may be applied to another body and this, in particular, has led to the discovery of the existence of heavy "meteoritic" bombardment in the early history of the solar system, which should also significantly affect Earth. It has been shown that volcanism and large-scale tectonics may have not only been an internal source of energy in the form of radiogenic decay of potassium, uranium and thorium, but also an external source in the form of gravity tugging caused by attractions of the neighboring bodies. The knowledge gained by lunar and planetary geology is important for planning and managing space missions and for the practical exploration of other bodies of the solar system and establishing manned outposts on them.

  11. Transition From NASA Space Communication Systems to Commerical Communication Products

    Science.gov (United States)

    Ghazvinian, Farzad; Lindsey, William C.

    1994-01-01

    Transitioning from twenty-five years of space communication system architecting, engineering and development to creating and marketing of commercial communication system hardware and software products is no simple task for small, high-tech system engineering companies whose major source of revenue has been the U.S. Government. Yet, many small businesses are faced with this onerous and perplexing task. The purpose of this talk/paper is to present one small business (LinCom) approach to taking advantage of the systems engineering expertise and knowledge captured in physical neural networks and simulation software by supporting numerous National Aeronautics and Space Administration (NASA) and the Department of Defense (DoD) projects, e.g., Space Shuttle, TDRSS, Space Station, DCSC, Milstar, etc. The innovative ingredients needed for a systems house to transition to a wireless communication system products house that supports personal communication services and networks (PCS and PCN) development in a global economy will be discussed. Efficient methods for using past government sponsored space system research and development to transition to VLSI communication chip set products will be presented along with notions of how synergy between government and industry can be maintained to benefit both parties.

  12. Phase transitions in glassy systems via convolutional neural networks

    Science.gov (United States)

    Fang, Chao

    Machine learning is a powerful approach commonplace in industry to tackle large data sets. Most recently, it has found its way into condensed matter physics, allowing for the first time the study of, e.g., topological phase transitions and strongly-correlated electron systems. The study of spin glasses is plagued by finite-size effects due to the long thermalization times needed. Here we use convolutional neural networks in an attempt to detect a phase transition in three-dimensional Ising spin glasses. Our results are compared to traditional approaches.

  13. Noise-induced transition in a quantum system

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Pulak Kumar [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Barik, Debashis [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Ray, Deb Shankar [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

    2005-07-04

    We examine the noise-induced transition in a fluctuating bistable potential of a driven quantum system in thermal equilibrium. Making use of a Wigner canonical thermal distribution for description of the statistical properties of the thermal bath, we explore the generic effects of quantization like vacuum field fluctuation and tunneling in the characteristic stationary probability distribution functions undergoing transition from unimodal to bimodal nature and in signal-to-noise ratio characterizing the cooperative effect among the noise processes and the weak periodic signal.

  14. Noise-induced transition in a quantum system

    International Nuclear Information System (INIS)

    Ghosh, Pulak Kumar; Barik, Debashis; Ray, Deb Shankar

    2005-01-01

    We examine the noise-induced transition in a fluctuating bistable potential of a driven quantum system in thermal equilibrium. Making use of a Wigner canonical thermal distribution for description of the statistical properties of the thermal bath, we explore the generic effects of quantization like vacuum field fluctuation and tunneling in the characteristic stationary probability distribution functions undergoing transition from unimodal to bimodal nature and in signal-to-noise ratio characterizing the cooperative effect among the noise processes and the weak periodic signal

  15. From Planetary Mapping to Map Production: Planetary Cartography as integral discipline in Planetary Sciences

    Science.gov (United States)

    Nass, Andrea; van Gasselt, Stephan; Hargitai, Hendrik; Hare, Trent; Manaud, Nicolas; Karachevtseva, Irina; Kersten, Elke; Roatsch, Thomas; Wählisch, Marita; Kereszturi, Akos

    2016-04-01

    Cartography is one of the most important communication channels between users of spatial information and laymen as well as the open public alike. This applies to all known real-world objects located either here on Earth or on any other object in our Solar System. In planetary sciences, however, the main use of cartography resides in a concept called planetary mapping with all its various attached meanings: it can be (1) systematic spacecraft observation from orbit, i.e. the retrieval of physical information, (2) the interpretation of discrete planetary surface units and their abstraction, or it can be (3) planetary cartography sensu strictu, i.e., the technical and artistic creation of map products. As the concept of planetary mapping covers a wide range of different information and knowledge levels, aims associated with the concept of mapping consequently range from a technical and engineering focus to a scientific distillation process. Among others, scientific centers focusing on planetary cartography are the United State Geological Survey (USGS, Flagstaff), the Moscow State University of Geodesy and Cartography (MIIGAiK, Moscow), Eötvös Loránd University (ELTE, Hungary), and the German Aerospace Center (DLR, Berlin). The International Astronomical Union (IAU), the Commission Planetary Cartography within International Cartographic Association (ICA), the Open Geospatial Consortium (OGC), the WG IV/8 Planetary Mapping and Spatial Databases within International Society for Photogrammetry and Remote Sensing (ISPRS) and a range of other institutions contribute on definition frameworks in planetary cartography. Classical cartography is nowadays often (mis-)understood as a tool mainly rather than a scientific discipline and an art of communication. Consequently, concepts of information systems, mapping tools and cartographic frameworks are used interchangeably, and cartographic workflows and visualization of spatial information in thematic maps have often been

  16. Planetary optical and infrared imaging

    International Nuclear Information System (INIS)

    Terrile, R.J.

    1988-01-01

    The purpose of this investigation is to obtain and analyze high spatial resolution charge coupled device (CCD) coronagraphic images of extra-solar planetary material and solar system objects. These data will provide information on the distribution of planetary and proto-planetary material around nearby stars leading to a better understanding of the origin and evolution of the solar system. Imaging within our solar system will provide information on the current cloud configurations on the outer planets, search for new objects around the outer planets, and provide direct support for Voyager, Galileo, and CRAF by imaging material around asteroids and clouds on Neptune. Over the last year this program acquired multispectral and polarization images of the disk of material around the nearby star Beta Pictoris. This material is believed to be associated with the formation of planets and provides a first look at a planetary system much younger than our own. Preliminary color and polarization data suggest that the material is very low albedo and similar to dark outer solar system carbon rich material. A coronagraphic search for other systems is underway and has already examined over 100 nearby stars. Coronagraphic imaging provided the first clear look at the rings of Uranus and albedo limits for the ring arcs around Neptune

  17. Resonant structure, formation and stability of the planetary system HD155358

    Science.gov (United States)

    Silburt, Ari; Rein, Hanno

    2017-08-01

    Two Jovian-sized planets are orbiting the star HD155358 near exact mean motion resonance (MMR) commensurability. In this work, we re-analyse the radial velocity (RV) data previously collected by Robertson et al. Using a Bayesian framework, we construct two models - one that includes and the other that excludes gravitational planet-planet interactions (PPIs). We find that the orbital parameters from our PPI and no planet-planet interaction (noPPI) models differ by up to 2σ, with our noPPI model being statistically consistent with previous results. In addition, our new PPI model strongly favours the planets being in MMR, while our noPPI model strongly disfavours MMR. We conduct a stability analysis by drawing samples from our PPI model's posterior distribution and simulating them for 109 yr, finding that our best-fitting values land firmly in a stable region of parameter space. We explore a series of formation models that migrate the planets into their observed MMR. We then use these models to directly fit to the observed RV data, where each model is uniquely parametrized by only three constants describing its migration history. Using a Bayesian framework, we find that a number of migration models fit the RV data surprisingly well, with some migration parameters being ruled out. Our analysis shows that PPIs are important to take into account when modelling observations of multiplanetary systems. The additional information that one can gain from interacting models can help constrain planet migration parameters.

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

    Science.gov (United States)

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

    2012-10-01

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

  19. Masses of the Planetary Nebula Central Stars in the Galactic Globular Cluster System from HST Imaging and Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jacoby, George H. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Marco, Orsola De [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Davies, James [Space Telescope Science Institute, Baltimore MD 21218 (United States); Lotarevich, I. [American Museum of Natural History, New York, NY (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Harrington, J. Patrick [University of Maryland, College Park, MD (United States); Lanz, Thierry, E-mail: gjacoby@lowell.edu, E-mail: orsola.demarco@mq.edu.au, E-mail: jdavies@stsci.edu, E-mail: heb11@psu.edu, E-mail: jph@astro.umd.edu, E-mail: thierry.lanz@oca.eu [Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, F-06304 Nice (France)

    2017-02-10

    The globular cluster (GC) system of our Galaxy contains four planetary nebulae (PNe): K 648 (or Ps 1) in M15, IRAS 18333-2357 in M22, JaFu 1 in Pal 6, and JaFu 2 in NGC 6441. Because single-star evolution at the low stellar mass of present-epoch GCs was considered incapable of producing visible PNe, their origin presented a puzzle. We imaged the PN JaFu 1 with the Hubble Space Telescope (HST) to obtain photometry of its central star (CS) and high-resolution morphological information. We imaged IRAS 18333-2357 with better depth and resolution, and we analyzed its archival HST spectra to constrain its CS temperature and luminosity. All PNe in Galactic GCs now have quality HST data, allowing us to improve CS mass estimates. We find reasonably consistent masses between 0.53 and 0.58 M {sub ⊙} for all four objects, though estimates vary when adopting different stellar evolutionary calculations. The CS mass of IRAS 18333-2357, though, depends strongly on its temperature, which remains elusive due to reddening uncertainties. For all four objects, we consider their CS and nebula masses, their morphologies, and other incongruities to assess the likelihood that these objects formed from binary stars. Although generally limited by uncertainties (∼0.02 M {sub ⊙}) in post-AGB tracks and core mass versus luminosity relations, the high-mass CS in K 648 indicates a binary origin. The CS of JaFu 1 exhibits compact, bright [O iii] and H α emission, like EGB 6, suggesting a binary companion or disk. Evidence is weaker for a binary origin of JaFu 2.

  20. Validation of a Rapid Bacteria Endospore Enumeration System for Planetary Protection Application

    Science.gov (United States)

    Chen, Fei; Kern, Roger; Kazarians, Gayane; Venkateswaran, Kasthuri

    NASA monitors spacecraft surfaces to assure that the presence of bacterial endospores meets strict criteria at launch, to minimize the risk of inadvertent contamination of the surface of Mars. Currently, the only approved method for enumerating the spores is a culture based assay that requires three days to produce results. In order to meet the demanding schedules of spacecraft assembly, a more rapid spore detection assay is being considered as an alternate method to the NASA standard culture-based assay. The Millipore Rapid Microbiology Detection System (RMDS) has been used successfully for rapid bioburden enumeration in the pharmaceutical and food industries. The RMDS is rapid and simple, shows high sensitivity (to 1 colony forming unit [CFU]/sample), and correlates well with traditional culture-based methods. It combines membrane filtration, adenosine triphosphate (ATP) bioluminescence chemistry, and image analysis based on photon detection with a Charge Coupled Device (CCD) camera. In this study, we have optimized the assay conditions and evaluated the use of the RMDS as a rapid spore detection tool for NASA applications. In order to select for spores, the samples were subjected to a heat shock step before proceeding with the RMDS incubation protocol. Seven species of Bacillus (nine strains) that have been repeatedly isolated from clean room environments were assayed. All strains were detected by the RMDS in 5 hours and these assay times were repeatedly demonstrated along with low image background noise. Validation experiments to compare the Rapid Sore Assay (RSA) and NASA standard assay (NSA) were also performed. The evaluation criteria were modeled after the FDA Guideline of Process Validation, and Analytical Test Methods. This body of research demonstrates that the Rapid Spore Assay (RSA) is quick, and of equivalent sensitivity to the NASA standard assay, potentially reducing the assay time for bacterial endospores from over 72 hours to less than 8 hours

  1. Assessing Sustainability Transition in the US Electrical Power System

    Directory of Open Access Journals (Sweden)

    Stephen McCauley

    2010-02-01

    Full Text Available This paper examines sustainability transition dynamics in the US electricity system, drawing on the socio-technical systems approach. We view system change as unfolding along several critical dimensions and geographical scales, including dynamics in the environment, science, civil society, discourse, and state regulatory institutions, as well as in capital and technology formations. A particular emphasis is given to the interaction of discourses, policy networks, and institutions. We trace four distinct regimes which have characterized the evolution of this discourse-network-institutional nexus over the last century. The research examines dynamics that present a challenge to the incumbent energy regime based on fossil fuels, nuclear and hydropower, and demonstrates how the actor-network supporting renewables and energy efficiency has grown stronger and more capable of moving toward a sustainability transition than at any time since the sustainable energy movement began a generation ago.

  2. Pairing symmetry transitions in the even-denominator FQHE system

    International Nuclear Information System (INIS)

    Nomura, Kentaro; Yoshioka, Daijiro

    2001-01-01

    Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane-Rezayi state, it is shown that the charging effect of a bilayer system which breaks the SU (2) symmetry of the pseudospin shifts the central charge and the conformal dimensions of the fermionic fields which describe the pseudospin sector in the edge theory. This corresponds to the transition from the Haldane-Rezayi state to Halperin's 331 state, or from a singlet d-wave to a triplet p-wave ABM type paired state in the composite fermion picture. Considering interlayer tunneling, the tunneling rate-capacitance phase diagram for the ν=5/2 paired bilayer system is discussed. (author)

  3. Pairing Symmetry Transitions in the Even-Denominator FQHE System

    Science.gov (United States)

    Nomura, Kentaro; Yoshioka, Daijiro

    2001-12-01

    Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane Rezayi state, it is shown that the charging effect of a bilayer system which breaks the SU(2) symmetry of the pseudospin shifts the central charge and the conformal dimensions of the fermionic fields which describe the pseudospin sector in the edge theory. This corresponds to the transition from the Haldane Rezayi state to Halperin's 331 state, or from a singlet d-wave to a triplet p-wave ABM type paired state in the composite fermion picture. Considering interlayer tunneling, the tunneling rate-capacitance phase diagram for the ν=5/2 paired bilayer system is discussed.

  4. Hyperchaos-chaos-hyperchaos transition in modified Roessler systems

    International Nuclear Information System (INIS)

    Nikolov, Svetoslav; Clodong, Sebastien

    2006-01-01

    We consider in this paper a family of modified hyperchaotic Roessler systems and investigate both problems of understanding hyperchaos-chaos-hyperchaos transition and computing the prediction time. These systems were obtained and numerically investigated by Nikolov and Clodong [Nikolov S, Clodong S. Occurrence of regular, chaotic and hyperchaotic behavior in a family of modified Rossler hyperchaotic systems. Chaos, Solitons and Fractals 2004;22:407-31]. Our studies confirm that transition hyperchaos-chaos-hyperchaos (i) depends on the change of the sign of the corresponding characteristic equation roots or (ii) can be obtained as a result of the absorption/repulsion of the repeller originally located out of the attractor by the growing attractor. It is also shown that the prediction time is a more reliable predictor of the evolution than the information dimension. We conclude that the prediction time in hyperchaotic regimes is at least one order of magnitude smaller than those in chaotic zones

  5. Dual-Priced Modal Transition Systems with Time Durations

    DEFF Research Database (Denmark)

    Beneš, Nikola; Kretínsky, Jan; Larsen, Kim Guldstrand

    2012-01-01

    Modal transition systems are a well-established specification formalism for a high-level modelling of component-based software systems. We present a novel extension of the formalism called modal transition systems with durations where time durations are modelled as controllable or uncontrollable...... intervals. We further equip the model with two kinds of quantitative aspects: each action has its own running cost per time unit, and actions may require several hardware components of different costs. We ask the question, given a fixed budget for the hardware components, what is the implementation...... with the cheapest long-run average reward. We give an algorithm for computing such optimal implementations via a reduction to a new extension of mean payoff games with time durations and analyse the complexity of the algorithm....

  6. Rheology of planetary ices

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B. [Lawrence Livermore National Lab., CA (United States); Kirby, S.H.; Stern, L.A. [Geological Survey, Menlo Park, CA (United States)

    1996-04-24

    The brittle and ductile rheology of ices of water, ammonia, methane, and other volatiles, in combination with rock particles and each other, have a primary influence of the evolution and ongoing tectonics of icy moons of the outer solar system. Laboratory experiments help constrain the rheology of solar system ices. Standard experimental techniques can be used because the physical conditions under which most solar system ices exist are within reach of conventional rock mechanics testing machines, adapted to the low subsolidus temperatures of the materials in question. The purpose of this review is to summarize the results of a decade-long experimental deformation program and to provide some background in deformation physics in order to lend some appreciation to the application of these measurements to the planetary setting.

  7. Hydrodynamic escape from planetary atmospheres

    Science.gov (United States)

    Tian, Feng

    Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Due to the existence of a singularity point near the transonic point, it is difficult to find transonic steady state solutions by solving the time-independent hydrodynamic equations. In addition to that, most previous works assume that all energy driving the escape flow is deposited in one narrow layer. This assumption not only results in less accurate solutions to the hydrodynamic escape problem, but also makes it difficult to include other chemical and physical processes in the hydrodynamic escape models. In this work, a numerical model describing the transonic hydrodynamic escape from planetary atmospheres is developed. A robust solution technique is used to solve the time dependent hydrodynamic equations. The method has been validated in an isothermal atmosphere where an analytical solution is available. The hydrodynamic model is applied to 3 cases: hydrogen escape from small orbit extrasolar planets, hydrogen escape from a hydrogen rich early Earth's atmosphere, and nitrogen/methane escape from Pluto's atmosphere. Results of simulations on extrasolar planets are in good agreement with the observations of the transiting extrasolar planet HD209458b. Hydrodynamic escape of hydrogen from other hypothetical close-in extrasolar planets are simulated and the influence of hydrogen escape on the long-term evolution of these extrasolar planets are discussed. Simulations on early Earth suggest that hydrodynamic escape of hydrogen from a hydrogen rich early Earth's atmosphere is about two orders magnitude slower than the diffusion limited escape rate. A hydrogen rich early Earth's atmosphere could have been maintained by the balance between the hydrogen escape and the supply of hydrogen into the atmosphere by volcanic outgassing. Origin of life may have occurred in the organic soup ocean created by the efficient formation of prebiotic molecules in the hydrogen rich early

  8. Five kepler target stars that show multiple transiting exoplanet candidates

    DEFF Research Database (Denmark)

    Steffen..[], Jason H.; Batalha, N. M.; Broucki, W J.

    2010-01-01

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets a...

  9. Planetary spectroscopy

    International Nuclear Information System (INIS)

    Fink, U.

    1988-01-01

    The main goal of the research is charge coupled device (CCD) spectroscopic and imaging studies of the solar system in support of spacecraft investigations. Studies include the physical behavior of comets, the atmosphere of the gaseous planets, and the solid surfaces of satellites and asteroids. The major observing program consisted of approximately 50 nights of photometry of Comet Halley in order to resolve the controversy over this comet's rotation period. This data is presently being analyzed. Additional observing projects included the spectroscopic occultation of Charon by Pluto, reflection spectroscopy of Mercury, and a spectrum of the satellite Oberon. Mercury data does not corroborate the Fe(++) absorption feature reported by McCord and Clark at 8800 A but instead potentially shows a weaker feature at longer wavelengths. This position is in much closer accord with expectations for Mercury since a band center near 8800 A implies too little Fe(++) on Mercury, especially if band shifts with temperature are considered. The Pluto project proved that the deep methane absorptions visible in their combined specta are due soley to Pluto with Charon showing a flat and featureless spectrum. It appears that if Charon ever contained a substantial methane component, the satellite's low surface gravity could not hold it and the methane evaporated and escaped

  10. Transitions of social-ecological subsistence systems in the Arctic

    Directory of Open Access Journals (Sweden)

    Per Fauchald

    2017-04-01

    Full Text Available Transitions of social-ecological systems (SES expose governance systems to new challenges. This is particularly so in the Arctic where resource systems are increasingly subjected to global warming, industrial development and globalization which subsequently alter the local SES dynamics. Based on common-pool resource theory, we developed a dynamic conceptual model explaining how exogenous drivers might alter a traditional subsistence system from a provisioning to an appropriation actions situation. In a provisioning action situation the resource users do not control the resource level but adapt to the fluctuating availability of resources, and the collective challenge revolve around securing the subsistence in the community. An increased harvest pressure enabled by exogenous drivers could transform the SES to an appropriation action situation where the collective challenge has changed to avoid overuse of a common-pool resource. The model was used as a focal lens to investigate the premises for broad-scale transitions of subsistence-oriented SESs in Arctic Alaska, Canada and Greenland. We synthesized data from documents, official statistics and grey and scientific literature to explore the different components of our model. Our synthesis suggests that the traditional Arctic subsistence SESs mostly comply with a provisioning action situation. Despite population growth and available technology; urbanization, increased wage labor and importation of food have reduced the resource demand, and we find no evidence for a broad-scale transition to an appropriation action situation throughout the Western Arctic. However, appropriation ­challenges have emerged in some cases either as a consequence of commercialization of the resource or by severely reduced resource stocks due to various exogenous drivers. Future transitions of SESs could be triggered by the emergence of commercial local food markets and Arctic warming. In particular, Arctic warming is an

  11. Transition of International System and China’s Strategic Choice

    Institute of Scientific and Technical Information of China (English)

    TANG YONGSHENG

    2016-01-01

    At present,the international situation is at change.The international system undergoes profound transition.Great changes are happening to structure of power pattern,essence of international relations and norms of global governance.Major events of overall and strategic bearings such as the Ukraine Crisis,the Chaos of the Middle East,the proliferation of terrorism and the slowdown in economic

  12. Sampling Transition Pathways in Highly Correlated Complex Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David

    2004-10-20

    This research grant supported my group's efforts to apply and extend the method of transition path sampling that we invented during the late 1990s. This methodology is based upon a statistical mechanics of trajectory space. Traditional statistical mechanics focuses on state space, and with it, one can use Monte Carlo methods to facilitate importance sampling of states. With our formulation of a statistical mechanics of trajectory space, we have succeeded at creating algorithms by which importance sampling can be done for dynamical processes. In particular, we are able to study rare but important events without prior knowledge of transition states or mechanisms. In perhaps the most impressive application of transition path sampling, my group combined forces with Michele Parrinello and his coworkers to unravel the dynamics of auto ionization of water [5]. This dynamics is the fundamental kinetic step of pH. Other applications concern nature of dynamics far from equilibrium [1, 7], nucleation processes [2], cluster isomerization, melting and dissociation [3, 6], and molecular motors [10]. Research groups throughout the world are adopting transition path sampling. In part this has been the result of our efforts to provide pedagogical presentations of the technique [4, 8, 9], as well as providing new procedures for interpreting trajectories of complex systems [11].

  13. Turning Planetary Theory Upside Down

    Science.gov (United States)

    2010-04-01

    The discovery of nine new transiting exoplanets is announced today at the RAS National Astronomy Meeting (NAM2010). When these new results were combined with earlier observations of transiting exoplanets astronomers were surprised to find that six out of a larger sample of 27 were found to be orbiting in the opposite direction to the rotation of their host star - the exact reverse of what is seen in our own Solar System. The new discoveries provide an unexpected and serious challenge to current theories of planet formation. They also suggest that systems with exoplanets of the type known as hot Jupiters are unlikely to contain Earth-like planets. "This is a real bomb we are dropping into the field of exoplanets," says Amaury Triaud, a PhD student at the Geneva Observatory who, with Andrew Cameron and Didier Queloz, leads a major part of the observational campaign. Planets are thought to form in the disc of gas and dust encircling a young star. This proto-planetary disc rotates in the same direction as the star itself, and up to now it was expected that planets that form from the disc would all orbit in more or less the same plane, and that they would move along their orbits in the same direction as the star's rotation. This is the case for the planets in the Solar System. After the initial detection of the nine new exoplanets [1] with the Wide Angle Search for Planets (WASP, [2]), the team of astronomers used the HARPS spectrograph on the 3.6-metre ESO telescope at the La Silla observatory in Chile, along with data from the Swiss Euler telescope, also at La Silla, and data from other telescopes to confirm the discoveries and characterise the transiting exoplanets [3] found in both the new and older surveys. Surprisingly, when the team combined the new data with older observations they found that more than half of all the hot Jupiters [4] studied have orbits that are misaligned with the rotation axis of their parent stars. They even found that six exoplanets in this

  14. Proto-planetary nebulae

    International Nuclear Information System (INIS)

    Zuckerman, B.

    1978-01-01

    A 'proto-planetary nebula' or a 'planetary nebula progenitor' is the term used to describe those objects that are losing mass at a rate >approximately 10 -5 Msolar masses/year (i.e. comparable to mass loss rates in planetary nebulae with ionized masses >approximately 0.2 Msolar masses) and which, it is believed, will become planetary nebulae themselves within 5 years. It is shown that most proto-planetary nebulae appear as very red objects although a few have been 'caught' near the middle of the Hertzsprung-Russell diagram. The precursors of these proto-planetaries are the general red giant population, more specifically probably Mira and semi-regular variables. (Auth.)end

  15. EMPIRICAL CONSTRAINTS ON TROJAN COMPANIONS AND ORBITAL ECCENTRICITIES IN 25 TRANSITING EXOPLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    Madhusudhan, N.; Winn, Joshua N.

    2009-01-01

    We present a search for Trojan companions to 25 transiting exoplanets. We use the technique of Ford and Gaudi, in which a difference is sought between the observed transit time and the transit time that is calculated by fitting a two-body Keplerian orbit to the radial-velocity data. This technique is sensitive to the imbalance of mass at the L4/L5 points of the planet-star orbit. No companions were detected above 2σ confidence. The median 2σ upper limit is 56 M + , and the most constraining limit is 2.8 M + for the case of GJ 436. A similar survey using forthcoming data from the Kepler satellite mission, along with the radial-velocity data that will be needed to confirm transit candidates, will be sensitive to 10-50 M + Trojan companions in the habitable zones of their parent stars. As a by-product of this study, we present empirical constraints on the eccentricities of the planetary orbits, including those which have previously been assumed to be circular. The limits on eccentricity are of interest for investigations of tidal circularization and for bounding possible systematic errors in the measured planetary radii and the predicted times of secondary eclipses.

  16. Photochemistry of Planetary Atmospheres

    Science.gov (United States)

    Yung, Y. L.

    2005-12-01

    The Space Age started half a century ago. Today, with the completion of a fairly detailed study of the planets of the Solar System, we have begun studying exoplanets (or extrasolar planets). The overriding question in is to ask whether an exoplanet is habitable and harbors life, and if so, what the biosignatures ought to be. This forces us to confront the fundamental question of what controls the composition of an atmosphere. The composition of a planetary atmosphere reflects a balance between thermodynamic equilibrium chemistry (as in the interior of giant planets) and photochemistry (as in the atmosphere of Mars). The terrestrial atmosphere has additional influence from life (biochemistry). The bulk of photochemistry in planetary atmospheres is driven by UV radiation. Photosynthesis may be considered an extension of photochemistry by inventing a molecule (chlorophyll) that can harvest visible light. Perhaps the most remarkable feature of photochemistry is catalytic chemistry, the ability of trace amounts of gases to profoundly affect the composition of the atmosphere. Notable examples include HOx (H, OH and HO2) chemistry on Mars and chlorine chemistry on Earth and Venus. Another remarkable feature of photochemistry is organic synthesis in the outer solar system. The best example is the atmosphere of Titan. Photolysis of methane results in the synthesis of more complex hydrocarbons. The hydrocarbon chemistry inevitably leads to the formation of high molecular weight products, giving rise to aerosols when the ambient atmosphere is cool enough for them to condense. These results are supported by the findings of the recent Cassini mission. Lastly, photochemistry leaves a distinctive isotopic signature that can be used to trace back the evolutionary history of the atmosphere. Examples include nitrogen isotopes on Mars and sulfur isotopes on Earth. Returning to the question of biosignatures on an exoplanet, our Solar System experience tells us to look for speciation

  17. CHARACTERIZING THE COOL KOIs. IV. KEPLER-32 AS A PROTOTYPE FOR THE FORMATION OF COMPACT PLANETARY SYSTEMS THROUGHOUT THE GALAXY

    International Nuclear Information System (INIS)

    Swift, Jonathan J.; Johnson, John Asher; Morton, Timothy D.; Montet, Benjamin T.; Muirhead, Philip S.; Crepp, Justin R.; Fabrycky, Daniel C.

    2013-01-01

    The Kepler space telescope has opened new vistas in exoplanet discovery space by revealing populations of Earth-sized planets that provide a new context for understanding planet formation. Approximately 70% of all stars in the Galaxy belong to the diminutive M dwarf class, several thousand of which lie within Kepler's field of view, and a large number of these targets show planet transit signals. The Kepler M dwarf sample has a characteristic mass of 0.5 M ☉ representing a stellar population twice as common as Sun-like stars. Kepler-32 is a typical star in this sample that presents us with a rare opportunity: five planets transit this star, giving us an expansive view of its architecture. All five planets of this compact system orbit their host star within a distance one-third the size of Mercury's orbit, with the innermost planet positioned a mere 4.3 stellar radii from the stellar photosphere. New observations limit possible false positive scenarios, allowing us to validate the entire Kepler-32 system making it the richest known system of transiting planets around an M dwarf. Based on considerations of the stellar dust sublimation radius, a minimum mass protoplanetary nebula, and the near period commensurability of three adjacent planets, we propose that the Kepler-32 planets formed at larger orbital radii and migrated inward to their present locations. The volatile content inferred for the Kepler-32 planets and order of magnitude estimates for the disk migration rates suggest that these planets may have formed beyond the snow line and migrated in the presence of a gaseous disk. If true, then this would place an upper limit on their formation time of ∼10 Myr. The Kepler-32 planets are representative of the full ensemble of planet candidates orbiting the Kepler M dwarfs for which we calculate an occurrence rate of 1.0 ± 0.1 planet per star. The formation of the Kepler-32 planets therefore offers a plausible blueprint for the formation of one of the largest

  18. Space and Planetary Resources

    Science.gov (United States)

    Abbud-Madrid, Angel

    2018-02-01

    The space and multitude of celestial bodies surrounding Earth hold a vast wealth of resources for a variety of space and terrestrial applications. The unlimited solar energy, vacuum, and low gravity in space, as well as the minerals, metals, water, atmospheric gases, and volatile elements on the Moon, asteroids, comets, and the inner and outer planets of the Solar System and their moons, constitute potential valuable resources for robotic and human space missions and for future use in our own planet. In the short term, these resources could be transformed into useful materials at the site where they are found to extend mission duration and to reduce the costly dependence from materials sent from Earth. Making propellants and human consumables from local resources can significantly reduce mission mass and cost, enabling longer stays and fueling transportation systems for use within and beyond the planetary surface. Use of finely grained soils and rocks can serve for habitat construction, radiation protection, solar cell fabrication, and food growth. The same material could also be used to develop repair and replacement capabilities using advanced manufacturing technologies. Following similar mining practices utilized for centuries on Earth, identifying, extracting, and utilizing extraterrestrial resources will enable further space exploration, while increasing commercial activities beyond our planet. In the long term, planetary resources and solar energy could also be brought to Earth if obtaining these resources locally prove to be no longer economically or environmentally acceptable. Throughout human history, resources have been the driving force for the exploration and settling of our planet. Similarly, extraterrestrial resources will make space the next destination in the quest for further exploration and expansion of our species. However, just like on Earth, not all challenges are scientific and technological. As private companies start working toward

  19. Gaussian dominance and phase transitions in systems with continuous symmetry

    International Nuclear Information System (INIS)

    Sankovich, D.P.

    1989-01-01

    In the framework of Froehlich's strategy in the theory of phase transitions in systems with continuous symmetry a condition on the interaction is obtained that leads to the existence of a Bose condensate in the model of a nonideal Bose gas at sufficiently low temperatures. It is shown that this conditions can be satisfied for the Huang-Davis and Huang-Yang-Luttinger models. The technique of majorizing estimates for the correlation functions based on the condition of local Gaussian dominance is used. An equation is obtained for the phase-transition temperature, an upper bound is obtained for the energy of the elementary excitations, and Bogolyubov's 1/q 2 singularity theorem is generalized

  20. Extrasolar Planetary Imaging Coronagraph

    Science.gov (United States)

    Clampin, M.

    2007-06-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F type stars which cannot be found with RV techniques, and observe the inner spatial structure and colors of debris disks. The robust mission design is simple and flexible ensuring mission success while minimizing cost and risk. The science payload consists of a heritage optical telescope assembly (OTA), and visible nulling coronagraph (VNC) instrument.

  1. NASA's "Eyes On The Solar System:" A Real-time, 3D-Interactive Tool to Teach the Wonder of Planetary Science

    Science.gov (United States)

    Hussey, K.

    2014-12-01

    NASA's Jet Propulsion Laboratory is using video game technology to immerse students, the general public and mission personnel in our solar system and beyond. "Eyes on the Solar System," a cross-platform, real-time, 3D-interactive application that can run on-line or as a stand-alone "video game," is of particular interest to educators looking for inviting tools to capture students interest in a format they like and understand. (eyes.nasa.gov). It gives users an extraordinary view of our solar system by virtually transporting them across space and time to make first-person observations of spacecraft, planetary bodies and NASA/ESA missions in action. Key scientific results illustrated with video presentations, supporting imagery and web links are imbedded contextually into the solar system. Educators who want an interactive, game-based approach to engage students in learning Planetary Science will see how "Eyes" can be effectively used to teach its principles to grades 3 through 14.The presentation will include a detailed demonstration of the software along with a description/demonstration of how this technology is being adapted for education. There will also be a preview of coming attractions. This work is being conducted by the Visualization Technology Applications and Development Group at NASA's Jet Propulsion Laboratory, the same team responsible for "Eyes on the Earth 3D," and "Eyes on Exoplanets," which can be viewed at eyes.nasa.gov/earth and eyes.nasa.gov/exoplanets.

  2. Acquisition of an Electron Back Scatter Diffraction (EBSD) system for the Zeiss Sigma SEM at Portland State University -- Planetary Major Equipment

    Science.gov (United States)

    Ruzicka, Alex

    To build on our parent Origins program award, entitled "Shock histories of chondrites as revealed by combined microstructural (TEM), petrographic, and X-ray microtomographic (micro-CT) analysis", we are requesting as Planetary Major Equipment the acquisition of an Electron Back Scatter Diffraction (EBSD) system, which will integrate with a Zeiss Sigma SEM that was installed at Portland State University last year (2010). This EBSD system will greatly augment the science return of the parent grant by allowing quantitative measurements of strain and textural fabrics in grains of all sizes and types across an entire thin section. Such measurements will help link data that are already being obtained with optical light microscopy, transmission electron microscopy, and micro- tomography methods. More generally, the EBSD system will augment the PI's research on the petrology of extraterrestrial materials by providing an additional tool for petrographic analyses, with data that can be used to evaluate strain, grain orientations, grain size distributions, phase proportions, and mineralogy. The equipment will enable quantitative characterization of the crystallography of primitive extraterrestrial materials, which will contribute to a better understanding of the formation and evolution of planetary systems, a major goal of NASA.

  3. Acquisition of an Electron Back Scatter Diffraction (EBSD) system for the Zeiss Sigma SEM at Portland State University Planetary Major Equipment

    Science.gov (United States)

    Ruzicka, Alex

    To build on our parent Origins program award, entitled "Shock histories of chondrites as revealed by combined microstructural (TEM), petrographic, and X-ray microtomographic (micro-CT) analysis", we are requesting as Planetary Major Equipment the acquisition of an Electron Back Scatter Diffraction (EBSD) system, which will integrate with a Zeiss Sigma SEM that was installed at Portland State University last year (2010). This EBSD system will greatly augment the science return of the parent grant by allowing quantitative measurements of strain and textural fabrics in grains of all sizes and types across an entire thin section. Such measurements will help link data that are already being obtained with optical light microscopy, transmission electron microscopy, and micro- tomography methods. More generally, the EBSD system will augment the PI's research on the petrology of extraterrestrial materials by providing an additional tool for petrographic analyses, with data that can be used to evaluate strain, grain orientations, grain size distributions, phase proportions, and mineralogy. The equipment will enable quantitative characterization of the crystallography of primitive extraterrestrial materials, which will contribute to a better understanding of the formation and evolution of planetary systems, a major goal of NASA.

  4. Line shape parameters for the H2O-H2 collision system for application to exoplanet and planetary atmospheres

    Science.gov (United States)

    Renaud, Candice L.; Cleghorn, Kara; Hartmann, Léna; Vispoel, Bastien; Gamache, Robert R.

    2018-05-01

    Water can be detected throughout the universe: in comets, asteroids, dwarf planets, the inner and outer planets in our solar system, cool stars, brown dwarfs, and on many exoplanets. Here the focus is on locations rich in hydrogen gas. To properly study these environments, there is a need for the line shape parameters for H2O transitions in collision with hydrogen. This work presents calculations of the half-width and line shift, made using the Modified Complex Robert-Bonamy (MCRB) formalism, at a number of temperatures. It is shown that this collision system is strongly off-resonance. For such conditions, the atom-atom part of the intermolecular potential dominates the interaction of the radiating and perturbing molecules. The atom-atom parameters were adjusted by fitting the H2O-H2 measurements of Brown and Plymate (1996). Several techniques were used to extract lines for which there is more confidence in the quality of the data. The final potential yields results that agree with the measurements with ∼0.3% difference and a 5.9% standard deviation. Using this potential, MCRB calculations were made for all transitions in the pure rotation, ν2, ν1, and ν3 bands. The structure of the line shape parameters and the temperature dependence of the half-width, as a function of the rotational and vibrational quantum numbers, are discussed. It is shown that the power law model of the T-dependence of the half-width is inadequate over large temperature ranges.

  5. Planning for planetary protection : challenges beyond Mars

    Science.gov (United States)

    Belz, Andrea P.; Cutts, James A.

    2006-01-01

    This document summarizes the technical challenges to planetary protection for these targets of interest and outlines some of the considerations, particularly at the system level, in designing an appropriate technology investment strategy for targets beyond Mars.

  6. Soft x-ray Planetary Imager

    Data.gov (United States)

    National Aeronautics and Space Administration — The project is to prototype a soft X-ray Imager for planetary applications that has the sensitivity to observe solar system sources of soft  X-ray emission. A strong...

  7. The Planetary Terrestrial Analogues Library (PTAL)

    Science.gov (United States)

    Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

    2018-04-01

    The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

  8. Magnetic phase transitions in low dimension quantum spin systems

    International Nuclear Information System (INIS)

    Canevet, Emmanuel

    2010-01-01

    In this PhD thesis, three low dimensional spin systems are studied by means of elastic and inelastic neutron scattering. Macroscopic measurements in the DMACuCl 3 compound indicate the coexistence of two kinds of dimers: antiferromagnetic and ferromagnetic. The magnetic structure determined by our neutron diffraction survey at H = 0 shows irrevocably the existence of these two kinds of dimers. It has been shown that the Ising-like compound BaCo 2 V 2 O 8 should be the first realization of a system in which a longitudinal spin density wave (LSDW) magnetic order occurs when a magnetic field is applied. In a first time, we have determined the magnetic structure in zero magnetic field. Then, we focused on the effect of a magnetic field on the propagation vector, showing an entrance in the LSDW phase at H c = 3.9 T. The magnetic structure refined above this critical field confirms that BaCo 2 V 2 O 8 is the first compound in which occurs a LSDW phase. In the organic compound DF 5 PNN, it has been shown that this compound is well described at low temperature by spin chains with alternating couplings. However, the crystallographic structure determined at room temperature implies that the interactions are uniform. By means of neutron diffraction, we characterized a structural transition at low temperature (T c = 450 mK) making the system evolve from C2/c space group to Pc. This transition explains the alternating behavior of the interactions. We have also evidenced a field-induced structural transition (H c = 1.1 T). Above this field, the system is back to the C2/c space group, implying that the interactions are back to uniform. We have confirmed this by studying the magnetic excitations. (author) [fr

  9. Understanding Global Change: A New Conceptual Framework To Guide Teaching About Planetary Systems And Both The Causes And Effects Of Changes In Those Systems

    Science.gov (United States)

    Levine, J.; Bean, J. R.

    2016-12-01

    Goals of the Next Generation Science Standards include understanding climate change and learning about ways to moderate the causes and mitigate the consequences of planetary-scale anthropogenic activities that interact synergistically to affect ecosystems and societies. The sheer number and scale of both causes and effects of global change can be daunting for teachers, and the lack of a clear conceptual framework for presenting this material usually leads educators (and textbooks) to present these phenomenon as a disjointed "laundry list." But an alternative approach is in the works. The Understanding Global Change web resource, currently under development at the UC Berkeley Museum of Paleontology, will provide educators with a conceptual framework, graphic models, lessons, and assessment templates for teaching NGSS-aligned, interdisciplinary, global change curricula. The core of this resource is an original informational graphic that presents and relates Earth's global systems, human and non-human factors that produce changes in those systems, and the effects of those changes that scientists can measure.

  10. Isotropic–Nematic Phase Transitions in Gravitational Systems

    Energy Technology Data Exchange (ETDEWEB)

    Roupas, Zacharias; Kocsis, Bence [Institute of Physics, Eötvös University, Pázmány P. s. 1/A, Budapest, 1117 (Hungary); Tremaine, Scott [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2017-06-20

    We examine dense self-gravitating stellar systems dominated by a central potential, such as nuclear star clusters hosting a central supermassive black hole. Different dynamical properties of these systems evolve on vastly different timescales. In particular, the orbital-plane orientations are typically driven into internal thermodynamic equilibrium by vector resonant relaxation before the orbital eccentricities or semimajor axes relax. We show that the statistical mechanics of such systems exhibit a striking resemblance to liquid crystals, with analogous ordered-nematic and disordered-isotropic phases. The ordered phase consists of bodies orbiting in a disk in both directions, with the disk thickness depending on temperature, while the disordered phase corresponds to a nearly isotropic distribution of the orbit normals. We show that below a critical value of the total angular momentum, the system undergoes a first-order phase transition between the ordered and disordered phases. At a critical point, the phase transition becomes second order, while for higher angular momenta there is a smooth crossover. We also find metastable equilibria containing two identical disks with mutual inclinations between 90° and 180°.

  11. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1980-01-01

    A two-component dust model is suggested to explain the infrared emission from planetary nebulae. A cold dust component located in the extensive remnant of the red-giant envelope exterior to the visible nebula is responsible for the far-infrared emission. A ward dust component, which is condensed after the formation of the planetary nebula and confined within the ionized gas shell, emits most of the near- and mid-infrared radiation. The observations of NGC 7027 are shown to be consisten with such a model. The correlation of silicate emission in several planetary nebulae with an approximately +1 spectral index at low radio frequencies suggests that both the silicate and radio emissions originate from the remnant of the circumstellar envelope of th precursor star and are observable only while the planetary nebula is young. It is argued that oxygen-rich stars as well as carbon-rich stars can be progenitors of planetary nebulae

  12. Significant achievements in the planetary geology program. Final report

    International Nuclear Information System (INIS)

    Head, J.W.

    1978-12-01

    Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include the following: constraints on solar system formation; asteriods, comets, and satellites; constraints on planetary interiors; volatiles and regoliths; instrument development techniques; planetary cartography; geological and geochemical constraints on planetary evolution; fluvial processes and channel formation; volcanic processes; Eolian processes; radar studies of planetary surfaces; cratering as a process, landform, and dating method; and the Tharsis region of Mars. Activities at a planetary geology field conference on Eolian processes are reported and techniques recommended for the presentation and analysis of crater size-frequency data are included

  13. EXPTIME-Completeness of Thorough Refinement on Modal Transition Systems

    DEFF Research Database (Denmark)

    Beneš, Nikola; Křetínský, Jan; Larsen, Kim Guldstrand

    2012-01-01

    Modal transition systems (MTS), a specification formalism introduced more than 20 years ago, has recently received a considerable attention in several different areas. Many of the fundamental questions related to MTSs have already been answered. However, the problem of the exact computational...... complexity of thorough refinement checking between two finite MTSs remained unsolved. We settle down this question by showing EXPTIME-completeness of thorough refinement checking on finite MTSs. The upper-bound result relies on a novel algorithm running in single exponential time providing a direct goal...

  14. World in transition 3 towards sustainable energy systems

    CERN Document Server

    2014-01-01

    'The publication of World in Transition: Towards Sustainable Energy Systems is timely indeed. The World Summit on Sustainable Development gave great prominence to this challenge, but failed to agree on a quantitative, time-bound target for the introduction of renewable energy sources. The German Advisory Council on Global Change (WBGU) has now produced a report with a global focus, which is essential in view of the global impacts of climate change. The report provides a convincing long-term analysis, which is also essential. Global energy policies have to take a long-term perspective, over the

  15. The Transiting Exocomets in the HD 172555 System

    Science.gov (United States)

    Grady, C. A.; Brown, A.; Kamp, I.; Roberge, A.; Riviere-Marichalar, P.; Welsh, B.

    2017-01-01

    The Earth is thought to have formed dry, in a part of the Solar Nebula deficient in organic material, and to have acquired its organics and water through bombardment by minor bodies. Observations of this process in well-dated systems can provide insight into the probable origin and composition of the bombarding parent bodies. Transiting cometary activity has previously been reported in Ca II for the late-A member of the 241 Myr old Pictoris Moving Group member, HD 172555(Kiefer et al. 2014). We present HST STIS and COS spectra of HD 172555 demonstrating that the star has chromospheric emission and variable in falling gas features in transitions of silicon and carbon ions at times when no Fe II absorption is seen in the UV data, and no Ca II absorption is seen in contemporary optical spectra. The lack of CO absorption and stable gas absorption at the system velocity is consistent with the absence of a cold Kuiper belt analog (Riviere-Marichalar et al. 2012) in this system. The presence of infall in some species at one epoch and others at different epochs suggests that, like Pictoris, there may be more than one family of exocomets. If perturbed into star-grazing orbits by the same mechanism as for Pic, these data suggest that the wide planet frequency among A-early F stars in the PMG is at least 37.5, well above the frequency estimated for young moving groups independent of host star spectral type.

  16. Preparing Graduate Students for Solar System Science and Exploration Careers: Internships and Field Training Courses led by the Lunar and Planetary Institute

    Science.gov (United States)

    Shaner, A. J.; Kring, D. A.

    2015-12-01

    To be competitive in 21st century science and exploration careers, graduate students in planetary science and related disciplines need mentorship and need to develop skills not always available at their home university, including fieldwork, mission planning, and communicating with others in the scientific and engineering communities in the U.S. and internationally. Programs offered by the Lunar and Planetary Institute (LPI) address these needs through summer internships and field training programs. From 2008-2012, LPI hosted the Lunar Exploration Summer Intern Program. This special summer intern program evaluated possible landing sites for robotic and human exploration missions to the lunar surface. By the end of the 2012 program, a series of scientifically-rich landing sites emerged, some of which had never been considered before. Beginning in 2015 and building on the success of the lunar exploration program, a new Exploration Science Summer Intern Program is being implemented with a broader scope that includes both the Moon and near-Earth asteroids. Like its predecessor, the Exploration Science Summer Intern Program offers graduate students a unique opportunity to integrate scientific input with exploration activities in a way that mission architects and spacecraft engineers can use. The program's activities may involve assessments and traverse plans for a particular destination or a more general assessment of a class of possible exploration targets. Details of the results of these programs will be discussed. Since 2010 graduate students have participated in field training and research programs at Barringer (Meteor) Crater and the Sudbury Impact Structure. Skills developed during these programs prepare students for their own thesis studies in impact-cratered terrains, whether they are on the Earth, the Moon, Mars, or other solar system planetary surface. Future field excursions will take place at these sites as well as the Zuni-Bandera Volcanic Field. Skills

  17. The mysterious age invariance of the planetary nebula luminosity function bright cut-off

    Science.gov (United States)

    Gesicki, K.; Zijlstra, A. A.; Miller Bertolami, M. M.

    2018-05-01

    Planetary nebulae mark the end of the active life of 90% of all stars. They trace the transition from a red giant to a degenerate white dwarf. Stellar models1,2 predicted that only stars above approximately twice the solar mass could form a bright nebula. But the ubiquitous presence of bright planetary nebulae in old stellar populations, such as elliptical galaxies, contradicts this: such high-mass stars are not present in old systems. The planetary nebula luminosity function, and especially its bright cut-off, is almost invariant between young spiral galaxies, with high-mass stars, and old elliptical galaxies, with only low-mass stars. Here, we show that new evolutionary tracks of low-mass stars are capable of explaining in a simple manner this decades-old mystery. The agreement between the observed luminosity function and computed stellar evolution validates the latest theoretical modelling. With these models, the planetary nebula luminosity function provides a powerful diagnostic to derive star formation histories of intermediate-age stars. The new models predict that the Sun at the end of its life will also form a planetary nebula, but it will be faint.

  18. The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Hardis, S.; Hinse, T. C.

    2012-01-01

    Aims: We present 11 high-precision photometric transit observations of the transiting super-Earth planet GJ1214b. Combining these data with observations from other authors, we investigate the ephemeris for possible signs of transit timing variations (TTVs) using a Bayesian approach. Methods......: The observations were obtained using telescope-defocusing techniques, and achieve a high precision with random errors in the photometry as low as 1mmag per point. To investigate the possibility of TTVs in the light curve, we calculate the overall probability of a TTV signal using Bayesian methods. Results...

  19. Planetary Landscape Geography

    Science.gov (United States)

    Hargitai, H.

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

  20. Characterization of the K2-18 multi-planetary system with HARPS. A habitable zone super-Earth and discovery of a second, warm super-Earth on a non-coplanar orbit

    Science.gov (United States)

    Cloutier, R.; Astudillo-Defru, N.; Doyon, R.; Bonfils, X.; Almenara, J.-M.; Benneke, B.; Bouchy, F.; Delfosse, X.; Ehrenreich, D.; Forveille, T.; Lovis, C.; Mayor, M.; Menou, K.; Murgas, F.; Pepe, F.; Rowe, J.; Santos, N. C.; Udry, S.; Wünsche, A.

    2017-12-01

    Aims: The bright M2.5 dwarf K2-18 (Ms = 0.36 M⊙, Rs = 0.41 R⊙) at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star's habitable zone; K2-18b. Given the superlative nature of this system for studying an exoplanetary atmosphere receiving similar levels of insolation as the Earth, we aim to characterize the planet's mass which is required to interpret atmospheric properties and infer the planet's bulk composition. Methods: We have obtained precision radial velocity measurements with the HARPS spectrograph. We then coupled those measurements with the K2 photometry to jointly model the observed radial velocity variation with planetary signals and a correlated stellar activity model based on Gaussian process regression. Results: We measured the mass of K2-18b to be 8.0 ± 1.9M⊕ with a bulk density of 3.3 ± 1.2 g/cm3 which may correspond to a predominantly rocky planet with a significant gaseous envelope or an ocean planet with a water mass fraction ≳50%. We also find strong evidence for a second, warm super-Earth K2-18c (mp,csinic = 7.5 ± 1.3 M⊕) at approximately nine days with a semi-major axis 2.4 times smaller than the transiting K2-18b. After re-analyzing the available light curves of K2-18 we conclude that K2-18c is not detected in transit and therefore likely has an orbit that is non-coplanar with the orbit of K2-18b although only a small mutual inclination is required for K2-18c to miss a transiting configuration; | Δi| 1-2°. A suite of dynamical integrations are performed to numerically confirm the system's dynamical stability. By varying the simulated orbital eccentricities of the two planets, dynamical stability constraints are used as an additional prior on each planet's eccentricity posterior from which we constrain eb multi-planet systems around M dwarfs. The characterization of the density of K2-18b reveals that the planet likely has a thick gaseous envelope which, along with its proximity to the solar

  1. The Topological Analysis of Urban Transit System as a Small-World Network

    OpenAIRE

    Zhaosheng Yang; Huxing Zhou; Peng Gao; Hong Chen; Nan Zhang

    2011-01-01

    This paper proposes a topological analysis of urban transit system based on a functional representation network constructed from the urban transit system in Beijing. The representation gives a functional view on nodes named a transit line. Statistical measures are computed and introduced in complex network analysis. It shows that the urban transit system forms small-world networks and exhibits properties different from random networks and regular networks. Furthermore, the topological propert...

  2. A Transitive Recommendation System for Information Technology Communities

    Directory of Open Access Journals (Sweden)

    Hesham Ali

    2013-06-01

    Full Text Available Social networks have become a new trend for research among computer scientist around the world. Social network had an impact on users' way of life. One of social network usages is recommendation systems. The need of recommendation systems is arising when users try to know best choice for them in many items types (books, experts, locations, technologies...etc. The problem is that a single person can't try all alternatives in all possibles life goals to compare. Thus, a person has to use his friends' expertise to select better option in any item category. This process is the main idea of “Recommendation Systems”. Recommendation systems usually depend on users-to-items ratings in a network (graph. Two main challenges for recommendation systems are accuracy of recommendation and computation size. The main objective of this paper is to introduce a suggested technique for transitive recommendation system based on users' collaborative ratings, and also to balance loading of computation. All this has to be applied on a special type of social network. Our work studied the transitivity usage in connections to get a relation (path as a recommendation for nodes not directly connected. The target social network has eight types of nodes. So, there are techniques that are not suitable to this complex type of network. Those we can present a new support for recommending items of several types to users with several types. We believe that this functionality hasn't been fully provided elsewhere. We have suggested using single source shortest path algorithm combined with Map Reduce technique, and mathematically deduced that we have a speeding up of algorithm by 10% approximately. Our testing results shows an accuracy of 89% and false rejection of 99% compared to traditional algorithms with less configuration parameters and more steady count of recommendations.

  3. Phase transitions in distributed control systems with multiplicative noise

    Science.gov (United States)

    Allegra, Nicolas; Bamieh, Bassam; Mitra, Partha; Sire, Clément

    2018-01-01

    Contemporary technological challenges often involve many degrees of freedom in a distributed or networked setting. Three aspects are notable: the variables are usually associated with the nodes of a graph with limited communication resources, hindering centralized control; the communication is subject to noise; and the number of variables can be very large. These three aspects make tools and techniques from statistical physics particularly suitable for the performance analysis of such networked systems in the limit of many variables (analogous to the thermodynamic limit in statistical physics). Perhaps not surprisingly, phase-transition like phenomena appear in these systems, where a sharp change in performance can be observed with a smooth parameter variation, with the change becoming discontinuous or singular in the limit of infinite system size. In this paper, we analyze the so called network consensus problem, prototypical of the above considerations, that has previously been analyzed mostly in the context of additive noise. We show that qualitatively new phase-transition like phenomena appear for this problem in the presence of multiplicative noise. Depending on dimensions, and on the presence or absence of a conservation law, the system performance shows a discontinuous change at a threshold value of the multiplicative noise strength. In the absence of the conservation law, and for graph spectral dimension less than two, the multiplicative noise threshold (the stability margin of the control problem) is zero. This is reminiscent of the absence of robust controllers for certain classes of centralized control problems. Although our study involves a ‘toy’ model, we believe that the qualitative features are generic, with implications for the robust stability of distributed control systems, as well as the effect of roundoff errors and communication noise on distributed algorithms.

  4. Participating to the Transition Towards New Energy Technology Systems

    International Nuclear Information System (INIS)

    Tosato, G.

    2008-01-01

    The paper analyses possible implications for Croatia of a global transition towards new energy technology systems, as depicted by the recent report on scenarios and strategies to 2050 of the International Energy Agency [ETP2008]. The analysis is based upon the present Croatian energy balance. It takes into account some draft results of the USAID-supported Regional Energy Demand Planning (REDP) study under the South East Europe Regional Energy Market Support (SEE REMS) Project. The paper then presents ongoing EC-funded energy research projects, such as RES2020 (Monitoring and Evaluation of the Renewable Energy Sources directives implementation in EU27 and policy recommendations for 2020), REACCESS (Risk of Energy Availability: Common Corridors for Europe Supply Security) and REALISEGRID (REseArch, methodoLogIes and technologieS for the effective development of pan-European key GRID infrastructures to support the achievement of a reliable, competitive and sustainable electricity supply). The participation of Croatian research organizations to EC-funded research projects could make the transition towards new energy system an opportunity for economic development.(author)

  5. Endothelial to mesenchymal transition in the cardiovascular system.

    Science.gov (United States)

    Gong, Hui; Lyu, Xing; Wang, Qiong; Hu, Min; Zhang, Xiangyu

    2017-09-01

    Endothelial to mesenchymal transition (EndMT) is a special type of epithelial to mesenchymal transition. It is a process that is characterized by the loss of features of endothelial cells and acquisition of specific markers of mesenchymal cells. A variety of stimuli, such as inflammation, growth factors, and hypoxia, regulate EndMT through various signaling pathways and intracellular transcription factors. It has been demonstrated that epigenetic modifications are also involved in this process. Recent studies have identified the essential role of EndMT in the cardiovascular system. EndMT contributes to steps in cardiovascular development, such as cardiac valve formation and septation, as well as the pathogenesis of various cardiovascular disorders, such as congenital heart disease, myocardial fibrosis, myocardial infarction and pulmonary arterial hypertension. Thus, comprehensive understanding of the underlying mechanisms of EndMT will provide novel therapeutic strategies to overcome congenital heart disease due to abnormal development and other cardiovascular diseases. This review will focus on summarizing the currently understood signaling pathways and epigenetic modifications involved in the regulation of EndMT and the role of EndMT in pathophysiological conditions of the cardiovascular system. Copyright © 2017. Published by Elsevier Inc.

  6. Soil Vapor Extraction System Optimization, Transition, and Closure Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J.; Becker, Dave; Simon, Michelle A.; Oostrom, Martinus; Rice, Amy K.; Johnson, Christian D.

    2013-02-08

    Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. A diminishing rate of contaminant extraction over time is typically observed due to 1) diminishing contaminant mass, and/or 2) slow rates of removal for contamination in low-permeability zones. After a SVE system begins to show indications of diminishing contaminant removal rate, SVE performance needs to be evaluated to determine whether the system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. This guidance specifically addresses the elements of this type of performance assessment. While not specifically presented, the approach and analyses in this guidance could also be applied at the onset of remediation selection for a site as a way to evaluate current or future impacts to groundwater from vadose zone contamination. The guidance presented here builds from existing guidance for SVE design, operation, optimization, and closure from the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and the Air Force Center for Engineering and the Environment. The purpose of the material herein is to clarify and focus on the specific actions and decisions related to SVE optimization, transition, and/or closure.

  7. MODELING OF DYNAMIC PROCESSES IN PLANETARY IN-WHEEL MOTOR GEARBOXES OF MINE TRUCKS DURING ITS STARTING AND ACCELERATION

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailov

    2012-01-01

    Full Text Available The paper describes a mathematical model for planetary double-row in-wheel motor gear box. Main parameters of its dynamic system have been determined in the paper. The paper reveals simulation of transition processes during starting and acceleration of a mine truck with electric motor wheels. Its own gear box frequency has been established theoretically and experimentally in the paper. The paper proposes an algorithm and program for calculations as an alternative to high-cost tests while investigating gear mechanism dynamics of large-size planetary gearboxes.

  8. Trends in Planetary Data Analysis. Executive summary of the Planetary Data Workshop

    Science.gov (United States)

    Evans, N.

    1984-09-01

    Planetary data include non-imaging remote sensing data, which includes spectrometric, radiometric, and polarimetric remote sensing observations. Also included are in-situ, radio/radar data, and Earth based observation. Also discussed is development of a planetary data system. A catalog to identify observations will be the initial entry point for all levels of users into the data system. There are seven distinct data support services: encyclopedia, data index, data inventory, browse, search, sample, and acquire. Data systems for planetary science users must provide access to data, process, store, and display data. Two standards will be incorporated into the planetary data system: Standard communications protocol and Standard format data unit. The data system configuration must combine a distributed system with those of a centralized system. Fiscal constraints have made prioritization important. Activities include saving previous mission data, planning/cost analysis, and publishing of proceedings.

  9. An ecological compass for planetary engineering.

    Science.gov (United States)

    Haqq-Misra, Jacob

    2012-10-01

    Proposals to address present-day global warming through the large-scale application of technology to the climate system, known as geoengineering, raise questions of environmental ethics relevant to the broader issue of planetary engineering. These questions have also arisen in the scientific literature as discussions of how to terraform a planet such as Mars or Venus in order to make it more Earth-like and habitable. Here we draw on insights from terraforming and environmental ethics to develop a two-axis comparative tool for ethical frameworks that considers the intrinsic or instrumental value placed upon organisms, environments, planetary systems, or space. We apply this analysis to the realm of planetary engineering, such as terraforming on Mars or geoengineering on present-day Earth, as well as to questions of planetary protection and space exploration.

  10. Five Kepler target stars that show multiple transiting exoplanet candidates

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Buchhave, Lars A.; /Harvard-Smithsonian Ctr. Astrophys. /Bohr Inst.; Caldwell, Douglas A.; /NASA, Ames /SETI Inst., Mtn. View; Cochran, William D.; /Texas U.; Endl, Michael; /Texas U.; Fabrycky, Daniel C.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Ford, Eric B.; /Florida U.; Fortney, Jonathan J.; /UC, Santa Cruz, Phys. Dept. /NASA, Ames

    2010-06-01

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities - two near 2:1 and one just outside 5:2. We discuss the implications that multitransiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories; as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTV) due to gravitational interactions - though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

  11. Field-induced phase transitions in antiferromagnetic systems

    International Nuclear Information System (INIS)

    Smeets, J.P.M.

    1984-05-01

    Neutron scattering experiments and magnetization measurements are carried out on cobalt bromide hexahydrate, of which 48% of the water molecules are replaced by deuterium oxide molecules. Results were compared with data obtained from non-deuterated cobalt bromide hexahydrate. Neutron scattering experiments showed the importance of the deuterium fraction. Interplay exists between the crystallographic system and the magnetic system, which is influenced by changing the deuterium fraction. Neutron scattering and magnetization experiments on partially deuterated RbFeCl 3 .2H 2 O and CsFeCl 3 .2H 2 O were performed to study the magnetic phase transitions in these quasi one-dimensional Ising compounds. The observed behaviour in the various phases can be described by the nucleation theory of chain reversals. (Auth.)

  12. Unbinding Transition of Probes in Single-File Systems

    Science.gov (United States)

    Bénichou, Olivier; Démery, Vincent; Poncet, Alexis

    2018-02-01

    Single-file transport, arising in quasi-one-dimensional geometries where particles cannot pass each other, is characterized by the anomalous dynamics of a probe, notably its response to an external force. In these systems, the motion of several probes submitted to different external forces, although relevant to mixtures of charged and neutral or active and passive objects, remains unexplored. Here, we determine how several probes respond to external forces. We rely on a hydrodynamic description of the symmetric exclusion process to obtain exact analytical results at long times. We show that the probes can either move as a whole, or separate into two groups moving away from each other. In between the two regimes, they separate with a different dynamical exponent, as t1 /4. This unbinding transition also occurs in several continuous single-file systems and is expected to be observable.

  13. The nutrition/excretion system of urban areas: socioecological regimes and transitions.

    OpenAIRE

    Esculier , Fabien

    2018-01-01

    Nutrition and excretion are fundamental physiological needs for all human beings. Analysis of their materiality, from the cellular scale up to the great planetary-scale biogeochemical cycles, shows that nutrition and excretion form a system. The focus of our study is the sustainability of the nutrition/excretion systems of urban areas, which we have sought to assess by analysing substance flows.The most relevant of these substances seems to be nitrogen, so by assessing urban nitrogen flows we...

  14. Challenges to China's transition to a low carbon electricity system

    International Nuclear Information System (INIS)

    Kahrl, Fredrich; Williams, Jim; Ding Jianhua; Hu Junfeng

    2011-01-01

    We examine the challenges to China's transition to a low carbon electricity system, in which renewable energy would play a significant role. China's electricity system currently lacks the flexibility in planning, operations, and pricing to respond to conflicting pressures from demand growth, rising costs, and environmental mandates in a way that simultaneously maintains reliability, decarbonizes the system, and keeps prices within acceptable bounds. Greater flexibility crucially requires the ability to more systematically and transparently manage and allocate costs. This will require re-orientating sector institutions still rooted in central planning, and strengthening independent regulation. Some of the necessary changes require fundamental political and legal reforms beyond the scope of energy policy. However, the system's flexibility can still be increased through the development of traditional planning and regulatory tools and approaches, such as an avoided cost basis for energy efficiency investments, more integrated planning to improve the coordination of generation, transmission, and demand-side investments, and a transparent ratemaking process. The judicious application of OECD electricity sector experience and skills can support these developments. - Research highlights: → China's electricity system currently lacks the flexibility to integrate renewables and reduce CO 2 emissions on a large scale at an acceptable cost and level of reliability. → The challenges to increased flexibility are more institutional than technological. → Chinese government agencies need new approaches to basic power system planning and ratemaking. → OECD countries can help address these challenges through the transfer of 'soft' technologies.

  15. Quantum phase transition in strongly correlated many-body system

    Science.gov (United States)

    You, Wenlong

    The past decade has seen a substantial rejuvenation of interest in the study of quantum phase transitions (QPTs), driven by experimental advance on the cuprate superconductors, the heavy fermion materials, organic conductors, Quantum Hall effect, Fe-As based superconductors and other related compounds. It is clear that strong electronic interactions play a crucial role in the systems of current interest, and simple paradigms for the behavior of such systems near quantum critical points remain unclear. Furthermore, the rapid progress in Feshbach resonance and optical lattice provides a flexible platform to study QPT. Quantum Phase Transition (QPT) describes the non-analytic behaviors of the ground-state properties in a many-body system by varying a physical parameter at absolute zero temperature - such as magnetic field or pressure, driven by quantum fluctuations. Such quantum phase transitions can be first-order phase transition or continuous. The phase transition is usually accompanied by a qualitative change in the nature of the correlations in the ground state, and describing this change shall clearly be one of our major interests. We address this issue from three prospects in a few strong correlated many-body systems in this thesis, i.e., identifying the ordered phases, studying the properties of different phases, characterizing the QPT points. In chapter 1, we give an introduction to QPT, and take one-dimensional XXZ model as an example to illustrate the QPT therein. Through this simple example, we would show that when the tunable parameter is varied, the system evolves into different phases, across two quantum QPT points. The distinct phases exhibit very different behaviors. Also a schematic phase diagram is appended. In chapter 2, we are engaged in research on ordered phases. Originating in the work of Landau and Ginzburg on second-order phase transition, the spontaneous symmetry breaking induces nonzero expectation of field operator, e.g., magnetization M

  16. Successfulness of bus rapid transit systems in Asia. Ex-post evaluation

    NARCIS (Netherlands)

    Kogdenko, Nadja

    2010-01-01

    SUMMARY Bus Rapid Transit (BRT) can be defined as “a bus-based mass transit system that delivers fast, comfortable, and cost-effective urban mobility”. It offers the opportunity to create a high-quality mass transit system at affordable costs, which is p

  17. 75 FR 43197 - Public Housing Assessment System (PHAS): Asset Management Transition Year 2 Extension

    Science.gov (United States)

    2010-07-23

    ... System (PHAS): Asset Management Transition Year 2 Extension AGENCY: Office of the Assistant Secretary for...): Asset Management Transition Year 2 Information (75 FR 1632), dated January 12, 2010, for PHAs with... Assessment System (PHAS): Asset Management Transition Year Information and Uniform Financial Reporting...

  18. The role of impact cratering in planetary environmental change and implications for the search for life in the solar system (Invited)

    Science.gov (United States)

    Osinski, G. R.

    2013-12-01

    Beginning in the late 18th century with the work of James Hutton, uniformitarianism emerged as a central tenet of the natural sciences and remained so well into the 20th century. Central to the idea of uniformitarianism is the concept of gradualism whereby processes throughout time occur at the same, or similar rates. In the 20th century, the idea that asteroids and comets have struck, and continue to strike, planetary bodies throughout geological time, has revolutionized our understanding of Solar System history and evolution. Indeed, it is now widely recognized that impact cratering is one of the most important and fundamental geological process in the Solar System. It is also now apparent that impact events have profoundly affected the origin and evolution of Earth, its environment, and the habitability of our planet. The extreme physical conditions (e.g., 10's of thousands of K and 100's of GPa), the concentrated nature of the energy release at a single point on a planetary surface, and the virtually instantaneous nature of the impact process sets apart impact events from all other geological processes. It should not be surprising then that such a rapid geological process can cause rapid environmental change. The destructive geological, environmental, and biological effects of meteorite impact events are well studied and well known. This is largely due to the discovery of the ~180 km diameter Chicxulub impact structure, Mexico, and its link to the mass extinction event that marks the end of the Cretaceous Period 65 Myr. ago. While the main driver for this mass extinction event remains debated, a long list of possible causes of environmental change have been proposed, including: heat from the impact explosion, tsunamis, earthquakes, global forest fires, dust injection in the upper atmosphere, production of vast quantities of N2O, and release of CO2 and sulfur species from the target rocks. Any one of these effects could potentially cause the annihilation of a

  19. Valuing real estate externality-based option in development of transit system projects.

    Science.gov (United States)

    2010-03-01

    Capital-intensive transit projects rely on strong public support and availability of funds. While the general : public has become a strong advocate for transit systems, budget shortfalls and financial constraints are still : resulting in delays in pr...

  20. Transition? What transition? : Changing energy systems in an increasingly carbon constrained world

    NARCIS (Netherlands)

    Mc Cahery, J.A.; Lopez de Silanes, Florencio; de Roode, Alexander

    2014-01-01

    Energy transitions have been taking place continuously since the Industrial Revolution. These transitions primarily involve national energy mixes. In general, countries keep moving up the energy ladder, meaning that they integrate larger and larger proportions of specialized fuels into their energy

  1. Quantum Phase Transitions in Conventional Matrix Product Systems

    Science.gov (United States)

    Zhu, Jing-Min; Huang, Fei; Chang, Yan

    2017-02-01

    For matrix product states(MPSs) of one-dimensional spin-1/2 chains, we investigate a new kind of conventional quantum phase transition(QPT). We find that the system has two different ferromagnetic phases; on the line of the two ferromagnetic phases coexisting equally, the system in the thermodynamic limit is in an isolated mediate-coupling state described by a paramagnetic state and is in the same state as the renormalization group fixed point state, the expectation values of the physical quantities are discontinuous, and any two spin blocks of the system have the same geometry quantum discord(GQD) within the range of open interval (0,0.25) and the same classical correlation(CC) within the range of open interval (0,0.75) compared to any phase having no any kind of correlation. We not only realize the control of QPTs but also realize the control of quantum correlation of quantum many-body systems on the critical line by adjusting the environment parameters, which may have potential application in quantum information fields and is helpful to comprehensively and deeply understand the quantum correlation, and the organization and structure of quantum correlation especially for long-range quantum correlation of quantum many-body systems.

  2. Vascular Remodelling and Mesenchymal Transition in Systemic Sclerosis

    Directory of Open Access Journals (Sweden)

    Pier Andrea Nicolosi

    2016-01-01

    Full Text Available Fibrosis of the skin and of internal organs, autoimmunity, and vascular inflammation are hallmarks of Systemic Sclerosis (SSc. The injury and activation of endothelial cells, with hyperplasia of the intima and eventual obliteration of the vascular lumen, are early features of SSc. Reduced capillary blood flow coupled with deficient angiogenesis leads to chronic hypoxia and tissue ischemia, enforcing a positive feed-forward loop sustaining vascular remodelling, further exacerbated by extracellular matrix accumulation due to fibrosis. Despite numerous developments and a growing number of controlled clinical trials no treatment has been shown so far to alter SSc natural history, outlining the need of further investigation in the molecular pathways involved in the pathogenesis of the disease. We review some processes potentially involved in SSc vasculopathy, with attention to the possible effect of sustained vascular inflammation on the plasticity of vascular cells. Specifically we focus on mesenchymal transition, a key phenomenon in the cardiac and vascular development as well as in the remodelling of injured vessels. Recent work supports the role of transforming growth factor-beta, Wnt, and Notch signaling in these processes. Importantly, endothelial-mesenchymal transition may be reversible, possibly offering novel cues for treatment.

  3. Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data

    Science.gov (United States)

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

    2011-07-01

    On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R p R ⊕), 288 super-Earth-size (1.25 R ⊕ R p R ⊕), 662 Neptune-size (2 R ⊕ R p R ⊕), 165 Jupiter-size (6 R ⊕ R p R ⊕), and 19 up to twice the size of Jupiter (15 R ⊕ R p R ⊕). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.

  4. CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BY KEPLER. II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATA

    International Nuclear Information System (INIS)

    Borucki, William J.; Koch, David G.; Bryson, Stephen T.; Lissauer, Jack J.; Basri, Gibor; Marcy, Geoffrey W.; Batalha, Natalie; Brown, Timothy M.; Caldwell, Douglas; DeVore, Edna; Jenkins, Jon M.; Christensen-Dalsgaard, Joergen; Cochran, William D.; Dunham, Edward W.; Gautier, Thomas N.; Geary, John C.; Latham, David W.; Gilliland, Ronald; Gould, Alan; Howell, Steve B.

    2011-01-01

    On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R p + ), 288 super-Earth-size (1.25 R + ≤ R p + ), 662 Neptune-size (2 R + ≤ R p + ), 165 Jupiter-size (6 R + ≤ R p + ), and 19 up to twice the size of Jupiter (15 R + ≤ R p + ). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.

  5. Gazetteer of Planetary Nomenclature

    Data.gov (United States)

    National Aeronautics and Space Administration — Planetary nomenclature, like terrestrial nomenclature, is used to uniquely identify a feature on the surface of a planet or satellite so that the feature can be...

  6. Transition from closed system to Internet of Things: A study in standardizing building lighting systems

    NARCIS (Netherlands)

    Mathews, E.; Muller, G.

    2016-01-01

    Internet of Things (IoT) is triggering changes in lighting industry from the traditional closed and propriety systems to flexible, interoperable and service oriented systems. To address the challenges of this transition and catering the specific requirements of lighting networks, an Open

  7. Multi Optical Transition Radiation System for ATF2

    International Nuclear Information System (INIS)

    Alabau-Gonzalvo, Javier

    2012-01-01

    In this paper we describe the design, installation and first calibration tests of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. This system will be a valuable tool for measuring beam sizes and emittances coming from the ATF Damping Ring. With an optical resolution of about 2 (micro)m an original OTR design (OTR1X) located after the septum at the entrance of the EXT line demonstrated the ability to measure a 5.5 (micro)m beam size in one beam pulse and to take many fast measurements. This gives the OTR the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter. Furthermore the nearby wire scanners will be a definitive test of the OTR as a beam emittance diagnostic device. The multi-OTR system design proposed here is based on the existing OTR1X.

  8. Pattern Transitions in Bacterial Oscillating System under Nanofluidic Confinement

    Science.gov (United States)

    Shen, Jie-Pan; Chou, Chia-Fu

    2011-03-01

    Successful binary fission in E. coli relies on remarkable oscillatory behavior of the MinCDE protein system to determine the exact division site. The most favorable models to explain this fascinating spatiotemporal regulation on dynamic MinDE pattern formation in cells are based on reaction-diffusion scenario. Although not fully understood, geometric factors caused by bacterial morphology play a crucial role in MinDE dynamics. In the present study, bacteria were cultured, confined and reshaped in various micro/nanofluidic devices, to mimic either curvature changes of cell peripherals. Fluorescence imaging was utilized to detail the mode transitions in multiple MinDE patterns. The understanding of the physics in multiple pattern formations is further complemented via in silico modeling. The study synergizes the join merits of in vivo, in vitro and in silico approaches, to grasp the insight of stochastic dynamics inherited from the noisy mesoscopic biophysics. We acknowledge support from the Foresight Project, Academia Sinica.

  9. Dependence of synchronization transitions on mean field approach in two-way coupled neural system

    Science.gov (United States)

    Shi, J. C.; Luo, M.; Huang, C. S.

    2018-03-01

    This work investigates the synchronization transitions in two-way coupled neural system by mean field approach. Results show that, there exists a critical noise intensity for the synchronization transitions, i.e., above (or below) the critical noise intensity, the synchronization transitions are decreased (or hardly change) with increasing the noise intensity. Meanwhile, the heterogeneity effect plays a negative role for the synchronization transitions, and above critical coupling strength, the heterogeneity effect on synchronization transitions can be negligible. Furthermore, when an external signal is introduced into the coupled system, the novel frequency-induced and amplitude-induced synchronization transitions are found, and there exist an optimal frequency and an optimal amplitude of external signal which makes the system to display the best synchronization transitions. In particular, it is observed that the synchronization transitions can not be further affected above critical frequency of external signal.

  10. Lessons learned from planetary science archiving

    Science.gov (United States)

    Zender, J.; Grayzeck, E.

    2006-01-01

    The need for scientific archiving of past, current, and future planetary scientific missions, laboratory data, and modeling efforts is indisputable. To quote from a message by G. Santayama carved over the entrance of the US Archive in Washington DC “Those who can not remember the past are doomed to repeat it.” The design, implementation, maintenance, and validation of planetary science archives are however disputed by the involved parties. The inclusion of the archives into the scientific heritage is problematic. For example, there is the imbalance between space agency requirements and institutional and national interests. The disparity of long-term archive requirements and immediate data analysis requests are significant. The discrepancy between the space missions archive budget and the effort required to design and build the data archive is large. An imbalance exists between new instrument development and existing, well-proven archive standards. The authors present their view on the problems and risk areas in the archiving concepts based on their experience acquired within NASA’s Planetary Data System (PDS) and ESA’s Planetary Science Archive (PSA). Individual risks and potential problem areas are discussed based on a model derived from a system analysis done upfront. The major risk for a planetary mission science archive is seen in the combination of minimal involvement by Mission Scientists and inadequate funding. The authors outline how the risks can be reduced. The paper ends with the authors view on future planetary archive implementations including the archive interoperability aspect.

  11. Price Elasticity of Demand and Capacity-Restraint Transit Fare Strategy: A Case Study of Bangkok Mass Transit System

    Directory of Open Access Journals (Sweden)

    Ackchai Sirikijpanichkul

    2015-01-01

    Full Text Available Traffic congestion is a chronic problem of Bangkok. Similar to other metropolises, the city perpetually seeks for alternatives to road travel. Mass rapid transit seems to be the only way out that is expected to mitigate traffic congestion in the city. However, without common fare system, travelers need to pay an initial entrance fee every time they enter each transit system. This excess cost tapers the demand and affects the efficient use of the system. This research investigates the influence of fare price on transit use which is measured by price elasticity of demand and proposes the optimum fare price if the common fare is used. The analysis is based on the findings from the stated preference survey techniques. Finally, the conclusion on fare level that encourage more patronage, maintain service quality and operator revenue is addressed.

  12. Phase transitions in random uniaxial systems with dipolar interactions

    International Nuclear Information System (INIS)

    Schuster, H.G.

    1977-01-01

    The critical behaviour of random uniaxial ferromagnetic (ferroelectric) systems with both short range and long range dipolar interactions is investigated, using the field theoretic renormalization method of Brezin et al. for the free energy above and below transition point Tsub(c). The randomness is due to externally introduced fluctuations in the short range interactions (quenched case) or (and) magneto-elastic coupling to the lattice (annealed case). Strong deviations in the critical behaviour with respect to the pure systems are found. In the quenched case, e.g., the specific heat C and the coefficient f 2 (of M 3 in the equation of state, where M is the magnetization) change from C proportional to abs ln abs t abs abssup(1/3), f 2 proportional to abs ln abs t abs abs sup(1/3), f 2 proportional to abs ln abs t abs abs -1 in the pure system to C = A+- + C+-exp[-4√ 3 106 abs ln abs t abs abs], f 2 proportional to abs ln abs t abs abs sup(-1/2) (where t = (T-Tsub(c)) / Tsub(c) is the reduced temperature and A+-, C+- are constants) in the random situation. (orig.) [de

  13. Can planetary nebulae rotate

    International Nuclear Information System (INIS)

    Grinin, V.P.

    1982-01-01

    It is shown that the inclination of spectral lines observed in a number of planetary nebulae when the spectrograph slit is placed along the major axis, which is presently ascribed to nonuniform expansion of the shells, actually may be due to rotation of the nebulae about their minor axes, as Campbell and Moore have suggested in their reports. It is assumed that the rotation of the central star (or, if the core is a binary system, circular motions of gas along quasi-Keplerian orbits) serves as the source of the original rotation of a protoplanetary nebula. The mechanism providing for strengthening of the original rotation in the process of expansion of the shell is the tangential pressure of L/sub α/ radiation due to the anisotropic properties of the medium and radiation field. The dynamic effect produced by them is evidently greatest in the epoch when the optical depth of the nebula in the L/sub c/ continuum becomes on the order of unity in the course of its expansion

  14. Chiral-glass transition in a diluted dipolar-interaction Heisenberg system

    International Nuclear Information System (INIS)

    Zhang Kaicheng; Liu Guibin; Zhu Yan

    2011-01-01

    Recently, numerical simulations reveal that a spin-glass transition can occur in the three-dimensional diluted dipolar system. By defining the chirality of triple spins in a diluted dipolar Heisenberg spin glass, we study the chiral ordering in the system using parallel tempering algorithm and heat bath method. The finite-size scaling analysis reveals that the system undergoes a chiral-glass transition at finite temperature. - Highlights: → We define the chirality in a diluted dipolar Heisenberg system. → The system undergoes a chiral-glass transition at finite temperature. → We extract the critical exponents of the chiral-glass transition.

  15. A Synergistic Approach to Interpreting Planetary Atmospheres

    Science.gov (United States)

    Batalha, Natasha E.

    We will soon have the technological capability to measure the atmospheric composition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In contrast to jovian-like atmospheres, whose bulk compositions consist of hydrogen and helium, terrestrial planet atmospheres are likely comprised of high mean molecular weight secondary atmospheres, which have gone through a high degree of evolution. For example, present-day Mars has a frozen surface with a thin tenuous atmosphere, but 4 billion years ago it may have been warmed by a thick greenhouse atmosphere. Several processes contribute to a planet's atmospheric evolution: stellar evolution, geological processes, atmospheric escape, biology, etc. Each of these individual processes affects the planetary system as a whole and therefore they all must be considered in the modeling of terrestrial planets. In order to demonstrate the intricacies in modeling terrestrial planets, I use early Mars as a case study. I leverage a combination of one-dimensional climate, photochemical and energy balance models in order to create one self-consistent model that closely matches currently available climate data. One-dimensional models can address several processes: the influence of greenhouse gases on heating, the effect of the planet's geological processes (i.e. volcanoes and the carbonatesilicate cycle) on the atmosphere, the effect of rainfall on atmospheric composition and the stellar irradiance. After demonstrating the number of assumptions required to build a model, I look towards what exactly we can learn from remote observations of temperate Earths and Super Earths. However, unlike in-situ observations from our own solar system, remote sensing techniques need to be developed and understood in order to accurately characterize exo-atmospheres. I describe the models used to create synthetic transit transmission observations, which includes models of

  16. Analyzing planetary transits with a smartphone

    Science.gov (United States)

    Barrera-Garrido, Azael

    2015-03-01

    Today's smartphones are getting more sensors than ever as factory-installed accessories. The time when a luxury mobile phone had only vertical and GPS sensors is gone. New smartphones come equipped with multiple sensors for many physical parameters. Smartphones are becoming portable physics laboratory data loggers for a variety of measurements in mechanics, thermodynamics, electromagnetism, and optics. All sorts of possibilities are now open, provided their sensors are calibrated. Many examples using the sensors available in smartphones have been presented, mostly in this column and a few other publications, such as acceleration sensors,1-3 microphones,4,5 camera,6-8 and light sensors.9,10

  17. Redox Variations in Early Solar System Materials and Implications for Late Stage Planetary Accretion and Planet Formation

    Science.gov (United States)

    Righter, K.

    2017-01-01

    Oxygen fugacity plays an important role in determining the detailed physical and chemical aspects of planets and their building blocks. Basic chemical properties such as the amount of oxidized Fe in a mantle (as FeO), the nature of alloying elements in the core (S, C, H, O, Si), and the solubility of various volatile elements in the silicate and metallic portions of embryos and planets can influence physical properties such as the size of the core, the liquidus and solidus of the mantle and core, and the speciation of volatile compounds contributing to atmospheres. This paper will provide an overview of the range of fO2 variation observed in primitive and differentiated materials that may have participated in accretion (cosmic dust, Star-dust and meteorites), a comparison to observations of planetary fO2 (Mercury, Mars and Earth), and a discus-sion of timing of variation of fO2 within both early and later accreted materials. This overview is meant to promote discussion and interaction between students of these two stages of planet formation to identify areas where more work is needed.

  18. The Planetary Data System— Archiving Planetary Data for the use of the Planetary Science Community

    Science.gov (United States)

    Morgan, Thomas H.; McLaughlin, Stephanie A.; Grayzeck, Edwin J.; Vilas, Faith; Knopf, William P.; Crichton, Daniel J.

    2014-11-01

    NASA’s Planetary Data System (PDS) archives, curates, and distributes digital data from NASA’s planetary missions. PDS provides the planetary science community convenient online access to data from NASA’s missions so that they can continue to mine these rich data sets for new discoveries. The PDS is a federated system consisting of nodes for specific discipline areas ranging from planetary geology to space physics. Our federation includes an engineering node that provides systems engineering support to the entire PDS.In order to adequately capture complete mission data sets containing not only raw and reduced instrument data, but also calibration and documentation and geometry data required to interpret and use these data sets both singly and together (data from multiple instruments, or from multiple missions), PDS personnel work with NASA missions from the initial AO through the end of mission to define, organize, and document the data. This process includes peer-review of data sets by members of the science community to ensure that the data sets are scientifically useful, effectively organized, and well documented. PDS makes the data in PDS easily searchable so that members of the planetary community can both query the archive to find data relevant to specific scientific investigations and easily retrieve the data for analysis. To ensure long-term preservation of data and to make data sets more easily searchable with the new capabilities in Information Technology now available (and as existing technologies become obsolete), the PDS (together with the COSPAR sponsored IPDA) developed and deployed a new data archiving system known as PDS4, released in 2013. The LADEE, MAVEN, OSIRIS REx, InSight, and Mars2020 missions are using PDS4. ESA has adopted PDS4 for the upcoming BepiColumbo mission. The PDS is actively migrating existing data records into PDS4 and developing tools to aid data providers and users. The PDS is also incorporating challenge

  19. Influence of stellar duplicity on the form of planetary nebulae

    International Nuclear Information System (INIS)

    Kolesnik, I.G.; Pilyugin, L.S.

    1986-01-01

    Formation of planetary nebulae's spatial structures is considered. Simple expression for angular distribution of density in planetary nebulae is obtained. Bipolar structures are formed effectively in binary systems in which the velocity of the expanding shell around the main star is smaller than the orbital velocity of the satellite. Masses of satellites lie in the range 0.1-0.4Msub(sun). Theoretical isophotal contour map for the model of the planetary nebula NGC 3587 is consistent with observational data. It is shown that central stars of planetary nebulae are usually binary systems

  20. Research for the energy transition. The organization of the energy systems

    International Nuclear Information System (INIS)

    2017-01-01

    The volume on research for the energy transition includes contributions to the FVEE annual meeting 2016 concerning the following issues: status and perspectives of the energy transition, key technologies for the energy transition, political boundary conditions, development trends in photovoltaics, components for the energy supply (wind energy, hydrogen technologies, smart bioenergy concept, contribution of the geosphere), grids and storage systems for the energy transition, research network renewable energies.

  1. Strongly correlated electron systems and neutron scattering. Magnetism, superconductivity, structural phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Katano, Susumu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Neutron scattering experiments in our group on strongly correlated electron systems are reviewed Metal-insulator transitions caused by structural phase transitions in (La{sub 1-x}Sr{sub x}) MnO{sub 3}, a novel magnetic transition in the CeP compound, correlations between antiferromagnetism and superconductivity in UPd{sub 2}Al{sub 3} and so forth are discussed. Here, in this note, the phase transition of Mn-oxides was mainly described. (author)

  2. Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. VI. HD 238914 and TYC 3318-01333-1: two more Li-rich giants with planets

    Science.gov (United States)

    Adamów, M.; Niedzielski, A.; Kowalik, K.; Villaver, E.; Wolszczan, A.; Maciejewski, G.; Gromadzki, M.

    2018-05-01

    Context. We present the latest results of our search for planets with HARPS-N at the 3.6 m Telescopio Nazionale Galileo under the Tracking Advanced Planetary Systems project: an in-depth study of the 15 most Li abundant giants from the PennState - Toruń Planet Search sample. Aims: Our goals are first, to obtain radial velocities of the most Li-rich giants we identified in our sample to search for possible low-mass substellar companions, and second, to perform an extended spectral analysis to define the evolutionary status of these stars. Methods: This work is based on high-resolution spectra obtained with the Hobby-Eberly Telescope and its High Resolution Spectrograph, and with the HARPS-N spectrograph at the Telescopio Nazionale Galileo. Two stars, HD 181368 and HD 188214, were also observed with UVES at the VLT to determine beryllium abundances. Results: We report i) the discovery of two new planetary systems around the Li-rich giant stars: HD 238914 and TYC 3318-01333-1 (a binary system); ii) reveal a binary Li-rich giant, HD 181368; iii) although our current phase coverage is not complete, we suggest the presence of planetary mass companions around TYC 3663-01966-1 and TYC 3105-00152-1; iv) we confirm the previous result for BD+48 740 and present updated orbital parameters, and v) we find a lack of a relation between the Li enhancement and the Be abundance for the stars HD 181368 and HD 188214, for which we acquired blue spectra. Conclusions: We found seven stars with stellar or potential planetary companions among the 15 Li-rich giant stars. The binary star frequency of the Li-rich giants in our sample appears to be normal, but the planet frequency is twice that of the general sample, which suggests a possible connection between hosting a companion and enhanced Li abundance in giant stars. We also found most of the companions orbits to be highly eccentric. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the

  3. No variations in transit times for Qatar-1 b

    Science.gov (United States)

    Maciejewski, G.; Fernández, M.; Aceituno, F. J.; Ohlert, J.; Puchalski, D.; Dimitrov, D.; Seeliger, M.; Kitze, M.; Raetz, St.; Errmann, R.; Gilbert, H.; Pannicke, A.; Schmidt, J.-G.; Neuhäuser, R.

    2015-05-01

    Aims: The transiting hot-Jupiter planet Qatar-1 b exhibits variations in transit times that could be perturbative. A hot Jupiter with a planetary companion on a nearby orbit would constitute an unprecedented planetary configuration, which is important for theories of the formation and evolution of planetary systems. We performed a photometric follow-up campaign to confirm or refute transit timing variations. Methods: We extend the baseline of transit observations by acquiring 18 new transit light curves acquired with 0.6-2.0 m telescopes. These photometric time series, together with data available in the literature, were analyzed in a homogenous way to derive reliable transit parameters and their uncertainties. Results: We show that the dataset of transit times is consistent with a linear ephemeris leaving no hint of any periodic variations with a range of 1 min. We find no compelling evidence of a close-in planetary companion to Qatar-1 b. This finding is in line with a paradigm that hot Jupiters are not components of compact multiplanetary systems. Based on dynamical simulations, we place tighter constraints on the mass of any fictitious nearby planet in the system. Furthermore, new transit light curves allowed us to redetermine system parameters with better precision than reported in previous studies. Our values generally agree with previous determinations. Partly based on (1) data collected with telescopes at the Rozhen National Astronomical Observatory and (2) observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.Tables of light curve data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/577/A109

  4. Clogging transition of many-particle systems flowing through bottlenecks

    Science.gov (United States)

    Zuriguel, Iker; Parisi, Daniel Ricardo; Hidalgo, Raúl Cruz; Lozano, Celia; Janda, Alvaro; Gago, Paula Alejandra; Peralta, Juan Pablo; Ferrer, Luis Miguel; Pugnaloni, Luis Ariel; Clément, Eric; Maza, Diego; Pagonabarraga, Ignacio; Garcimartín, Angel

    2014-12-01

    When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance.

  5. The Planetary Science Archive (PSA): Exploration and discovery of scientific datasets from ESA's planetary missions

    Science.gov (United States)

    Vallat, C.; Besse, S.; Barbarisi, I.; Arviset, C.; De Marchi, G.; Barthelemy, M.; Coia, D.; Costa, M.; Docasal, R.; Fraga, D.; Heather, D. J.; Lim, T.; Macfarlane, A.; Martinez, S.; Rios, C.; Vallejo, F.; Said, J.

    2017-09-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific datasets through various interfaces at http://psa.esa.int. All datasets are scientifically peer-reviewed by independent scientists, and are compliant with the Planetary Data System (PDS) standards. The PSA has started to implement a number of significant improvements, mostly driven by the evolution of the PDS standards, and the growing need for better interfaces and advanced applications to support science exploitation.

  6. Investigations on physics of planetary atmospheres and small bodies of the Solar system, extrasolar planets and disk structures around the stars

    Science.gov (United States)

    Vidmachenko, A. P.; Delets, O. S.; Dlugach, J. M.; Zakhozhay, O. V.; Kostogryz, N. M.; Krushevska, V. M.; Kuznyetsova, Y. G.; Morozhenko, O. V.; Nevodovskyi, P. V.; Ovsak, O. S.; Rozenbush, O. E.; Romanyuk, Ya. O.; Shavlovskiy, V. I.; Yanovitskij, E. G.

    2015-12-01

    The history and main becoming stages of Planetary system physics Department of the Main astronomical observatory of National academy of Sciences of Ukraine are considered. Fundamental subjects of department researches and science achievements of employees are presented. Fields of theoretical and experimental researches are Solar system planets and their satellites; vertical structures of planet atmospheres; radiative transfer in planet atmospheres; exoplanet systems of Milky Way; stars having disc structures; astronomical engineering. Employees of the department carry out spectral, photometrical and polarimetrical observations of Solar system planets, exoplanet systems and stars with disc structures. 1. From the history of department 2. The main directions of department research 3. Scientific instrumentation 4. Telescopes and observation stations 5. Theoretical studies 6. The results of observations of planets and small Solar system bodies and their interpretation 7. The study of exoplanets around the stars of our galaxy 8. Spectral energy distribution of fragmenting protostellar disks 9. Cooperation with the National Technical University of Ukraine (KPI) and National University of Ukraine "Lviv Polytechnic" to study the impact of stratospheric aerosol changes on weather and climate of the Earth 10. International relations. Scientific and organizational work. Scientific conferences, congresses, symposia 11. The main achievements of the department 12. Current researches 13. Anniversaries and awards

  7. Phase transitions, scaling and renormalisation in nonequilibrium systems

    International Nuclear Information System (INIS)

    Hanney, T.E.

    2002-01-01

    Nonequilibrium phase transitions and critical phenomena in simple lattice-based interacting particle models are considered. Specific models of interest are exclusion models in low dimensions, with particular reference to the asymmetric simple exclusion process (ASEP) which provides a testbed for many of the calculations. The aim of the thesis is to devise approximate scaling techniques for such models which account for fluctuations and which are more widely applicable than methods pursuing an exact solution. Scaling techniques which have been applied to models described by a linear equation of motion are extended to the case where the equation of motion is nonlinear. These methods capture the dynamic transition in the ASEP but fail to properly account for the nonlinearity in their predictions for the dynamic exponent, z. A new and widely applicable real space renormalisation group procedure is developed. It provides a direct and transparent scaling method to extract universal and non-universal properties of the steady state and dynamic critical behaviour in the boundary-driven ASEP in one dimension. In particular, we obtain a flow diagram for the problem from which we can interpret all the qualitative features of the (exactly known) steady state phase diagram and which predicts the exact value for the critical point. Further, the dynamic scaling is consistent with a crossover between diflusive behaviour near the zero current fixed point and z = 3/2 dynamics at the critical fixed point. Extensions to include disorder, to higher dimensions, and to other models are all possible using the method. Using the mapping between the Master equation and the Schroedinger equation in imaginary time, this scaling procedure is rephrased as a new blocking for quantum-spin systems. Existing methods of real space renormalisation for quantum-spin systems are applied to a variety of previously unconsidered exclusion models. In particular, it is shown how such techniques can be applied

  8. Transitioning a Chesapeake Bay Ecological Prediction System to Operations

    Science.gov (United States)

    Brown, C.; Green, D. S.; Eco Forecasters

    2011-12-01

    phase, the sea surface temperature (SST) and sea surface salinity (SSS) fields are generated by the Chesapeake Bay Operational Forecast System (CBOFS2), a 3-dimensional hydrodynamic model developed and operated by NOAA's National Ocean Service and run operationally at the National Weather Service National Centers for Environmental Prediction (NCEP). Importantly, this system is readily modified to predict the probability of other important target organisms, such as harmful algal blooms, biogeochemical constituents, such as dissolved oxygen concentration, and water-borne pathogens. Extending this initial effort includes advancement of a regional coastal ocean modeling testbed and proving ground. Such formal collaboration is intended to accelerate transition to operations and increase confidence and use of forecast guidance. The outcome will be improved decision making by emergency and resource managers, scientific researchers and the general public. The presentation will describe partnership plans for this testbed as well as the potential implications for the services and research community.

  9. Sustainable transition of socio-technological systems: How can Governance Network Research and Transition Theory contribute to the transition to biofuel for transportation?

    DEFF Research Database (Denmark)

    Hansen, Ole Erik; Stærdahl, Jens; Søndergård, Bent

    -technological systems, calling attention to how such governance structures emerge, stabilize and become dominant, which functions governance structures have to serve to become efficient, and how they can be made subject to deliberate and purposeful shaping and transition. Taking this approach, research in planning...

  10. Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System

    DEFF Research Database (Denmark)

    Gregersen, Tine; Haase, Anne-Mette; Schlageter, Vincent

    2015-01-01

    BACKGROUND/AIMS: The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea re-stricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not ...

  11. Collisional stripping of planetary crusts

    Science.gov (United States)

    Carter, Philip J.; Leinhardt, Zoë M.; Elliott, Tim; Stewart, Sarah T.; Walter, Michael J.

    2018-02-01

    Geochemical studies of planetary accretion and evolution have invoked various degrees of collisional erosion to explain differences in bulk composition between planets and chondrites. Here we undertake a full, dynamical evaluation of 'crustal stripping' during accretion and its key geochemical consequences. Crusts are expected to contain a significant fraction of planetary budgets of incompatible elements, which include the major heat producing nuclides. We present smoothed particle hydrodynamics simulations of collisions between differentiated rocky planetesimals and planetary embryos. We find that the crust is preferentially lost relative to the mantle during impacts, and we have developed a scaling law based on these simulations that approximates the mass of crust that remains in the largest remnant. Using this scaling law and a recent set of N-body simulations of terrestrial planet formation, we have estimated the maximum effect of crustal stripping on incompatible element abundances during the accretion of planetary embryos. We find that on average approximately one third of the initial crust is stripped from embryos as they accrete, which leads to a reduction of ∼20% in the budgets of the heat producing elements if the stripped crust does not reaccrete. Erosion of crusts can lead to non-chondritic ratios of incompatible elements, but the magnitude of this effect depends sensitively on the details of the crust-forming melting process on the planetesimals. The Lu/Hf system is fractionated for a wide range of crustal formation scenarios. Using eucrites (the products of planetesimal silicate melting, thought to represent the crust of Vesta) as a guide to the Lu/Hf of planetesimal crust partially lost during accretion, we predict the Earth could evolve to a superchondritic 176Hf/177Hf (3-5 parts per ten thousand) at present day. Such values are in keeping with compositional estimates of the bulk Earth. Stripping of planetary crusts during accretion can lead to

  12. Phase transition in vortex system in Bi2212:Pb monocrystal

    CERN Document Server

    Uspenskaya, L S; Rakhmanov, A L

    2002-01-01

    Penetration of the magnetic flux into the (Bi sub 0 sub . sub 8 sub 4 Pb sub 0 sub . sub 1 sub 6) sub 2 sub . sub 2 Sr sub 2 CaCu sub 2 O sub 8 high-temperature superconductor monocrystal is studied thorough the magnetooptical method in the crossed magnetic fields. It is shown that the magnetic flux penetration in the low-temperature areas is anisotropic: it moves primarily along the magnetic field, applied in the sample plane, and this anisotropy grows with the temperature growth. At the temperature of T sub m = 54 +- 2 K there takes place sharp change in the character of the magnetic field penetration into the superconductor, whereby the direction of the flux motion discontinues to be dependent on the direction and value of the magnetic field applied in the sample plane. This effect is interpreted within the frames of representations on the phase transition in the vortex system connected with a sharp decrease in the correlations of the vortex position in the different CuO-planes

  13. Weighted Complex Network Analysis of Shanghai Rail Transit System

    Directory of Open Access Journals (Sweden)

    Yingying Xing

    2016-01-01

    Full Text Available With increasing passenger flows and construction scale, Shanghai rail transit system (RTS has entered a new era of networking operation. In addition, the structure and properties of the RTS network have great implications for urban traffic planning, design, and management. Thus, it is necessary to acquire their network properties and impacts. In this paper, the Shanghai RTS, as well as passenger flows, will be investigated by using complex network theory. Both the topological and dynamic properties of the RTS network are analyzed and the largest connected cluster is introduced to assess the reliability and robustness of the RTS network. Simulation results show that the distribution of nodes strength exhibits a power-law behavior and Shanghai RTS network shows a strong weighted rich-club effect. This study also indicates that the intentional attacks are more detrimental to the RTS network than to the random weighted network, but the random attacks can cause slightly more damage to the random weighted network than to the RTS network. Our results provide a richer view of complex weighted networks in real world and possibilities of risk analysis and policy decisions for the RTS operation department.

  14. The Analysis of Distribution of Thickness of ThinFilm Coating During the Magnetron Sputtering on Systems with Planetary Movement of Substrate

    Directory of Open Access Journals (Sweden)

    H. R. Sagatelyan

    2014-01-01

    Full Text Available The article subject is a thin-film coating process using ion-plasma sputter deposition systems with magnetron sputtering targets. To improve coating thickness evenness of parts various manufacturers equip their systems with mechanisms for moving the coating parts, and sometimes the magnetrons. More specifically, the article concerns the ion-plasma sputtering process using a system equipped with a mechanism for providing a planetary movement of the coating parts in the plane perpendicular to the planes of two sputtering targets.The purpose of this work was to improve a distribution of the coating thickness evenness on the sputtering surface of the part. It is achieved through selection of the best combinations of kinematic and geometric factors that characterize a particular sputtering operation, depending on the size and position of the surface to be coated. These factors include a ratio between directions and frequencies of the self-rotation of satellite planetary gear, which holds a work piecesubstrate, and the translational motion i.e. planetary carrier rotation to carry the satellite; the angles of planes of the right and left magnetrons with respect to the system frontal plane. Since there is, essentially, a lack of mathematical models to perform the appropriate calculations for the considered type of system designs, a more specific aim of the article is to develop a technique to evaluate the uneven thickness of coatings provided by the systems of this type.To achieve this more specific purpose the analytical technique had been used, applying the postulates of analytical geometry and theoretical mechanics. The main results of the research described in the article are as follows:- mathematical models of dependencies of geometric and kinematic parameters, changing during the sputtering process and characterizing each considered point on the surface of the work piece, on the current position of the work piece in the structure of the planetary

  15. Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System.

    Science.gov (United States)

    Gregersen, Tine; Haase, Anne-Mette; Schlageter, Vincent; Gronbaek, Henning; Krogh, Klaus

    2015-07-30

    The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea re-stricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients' regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. Fifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were inves-tigated with 3D-Transit and standard radiopaque markers. Total GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman's rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5-47.2) hours in patients versus 25.1 (range: 13.1-142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4-5.5) hours in patients versus 4.4 (range: 1.8-7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9-40.1) hours in patients versus 18.1 (range: 5.0-134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental co-lonic movements was 0.45 (range: 0.03-1.02) per hour in patients and 0.07 (range: 0-0.61) per hour in healthy subjects (P = 0.045). Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency of pansegmental colonic movements.

  16. Planetary Geologic Mapping Handbook - 2010. Appendix

    Science.gov (United States)

    Tanaka, K. L.; Skinner, J. A., Jr.; Hare, T. M.

    2010-01-01

    the USGS now are primarily digital products using geographic information system (GIS) software and file formats. GIS mapping tools permit easy spatial comparison, generation, importation, manipulation, and analysis of multiple raster image, gridded, and vector data sets. GIS software has also permitted the development of projectspecific tools and the sharing of geospatial products among researchers. GIS approaches are now being used in planetary geologic mapping as well. Guidelines or handbooks on techniques in planetary geologic mapping have been developed periodically. As records of the heritage of mapping methods and data, these remain extremely useful guides. However, many of the fundamental aspects of earlier mapping handbooks have evolved significantly, and a comprehensive review of currently accepted mapping methodologies is now warranted. As documented in this handbook, such a review incorporates additional guidelines developed in recent years for planetary geologic mapping by the NASA Planetary Geology and Geophysics (PGG) Program's Planetary Cartography and Geologic Mapping Working Group's (PCGMWG) Geologic Mapping Subcommittee (GEMS) on the selection and use of map bases as well as map preparation, review, publication, and distribution. In light of the current boom in planetary exploration and the ongoing rapid evolution of available data for planetary mapping, this handbook is especially timely.

  17. Developing Science Operations Concepts for the Future of Planetary Surface Exploration

    Science.gov (United States)

    Young, K. E.; Bleacher, J. E.; Rogers, A. D.; McAdam, A.; Evans, C. A.; Graff, T. G.; Garry, W. B.; Whelley,; Scheidt, S.; Carter, L.; hide

    2017-01-01

    Through fly-by, orbiter, rover, and even crewed missions, National Aeronautics and Space Administration (NASA) has been extremely successful in exploring planetary bodies throughout our Solar System. The focus on increasingly complex Mars orbiter and rover missions has helped us understand how Mars has evolved over time and whether life has ever existed on the red planet. However, large strategic knowledge gaps (SKGs) still exist in our understanding of the evolution of the Solar System (e.g. the Lunar Exploration Analysis Group, Small Bodies Analysis Group, and Mars Exploration Program Analysis Group). Sending humans to these bodies is a critical part of addressing these SKGs in order to transition to a new era of planetary exploration by 2050.

  18. Blue Marble Matches: Using Earth for Planetary Comparisons

    Science.gov (United States)

    Graff, Paige Valderrama

    2009-01-01

    Goal: This activity is designed to introduce students to geologic processes on Earth and model how scientists use Earth to gain a better understanding of other planetary bodies in the solar system. Objectives: Students will: 1. Identify common descriptor characteristics used by scientists to describe geologic features in images. 2. Identify geologic features and how they form on Earth. 3. Create a list of defining/distinguishing characteristics of geologic features 4. Identify geologic features in images of other planetary bodies. 5. List observations and interpretations about planetary body comparisons. 6. Create summary statements about planetary body comparisons.

  19. State transition storyboards: A tool for designing the Goldstone solar system radar data acquisition system user interface software

    Science.gov (United States)

    Howard, S. D.

    1987-01-01

    Effective user interface design in software systems is a complex task that takes place without adequate modeling tools. By combining state transition diagrams and the storyboard technique of filmmakers, State Transition Storyboards were developed to provide a detailed modeling technique for the Goldstone Solar System Radar Data Acquisition System human-machine interface. Illustrations are included with a description of the modeling technique.

  20. Visualizing NASA's Planetary Data with Google Earth

    Science.gov (United States)

    Beyer, R. A.; Hancher, M. D.; Broxton, M.; Weiss-Malik, M.; Gorelick, N.; Kolb, E.

    2008-12-01

    . Our presentation will demonstrate how to leverage the latest Google Earth and KML features to visualize planetary data. In the future we hope to make additional planetary KML data available for Mars, the Moon, and other planets in the solar system. This will vastly increase the public's ability to easily access NASA's store of planetary geospatial information.