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1. Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Author: T. Nakamura, M. Matsumoto, K. Amano, Y. Enokido, M. E. Zolensky, T. Mikouchi, H. Genda, S. Tanaka, M. Y. Zolotov, K. Kurosawa, S. Wakita, R. Hyodo, H. Nagano, D. Nakashima, Y. Takahashi, Y. Fujioka, M. Kikuiri, E. Kagawa, M. Matsuoka, A. J. Brearley, A. Tsuchiyama, M. Uesugi, J. Matsuno, Y. Kimura, M. Sato, R. E. Milliken, E. Tatsumi, S. Sugita, T. Hiroi, K. Kitazato, D. Brownlee, D. J. Joswiak, M. Takahashi, K. Ninomiya, T. Takahashi, T. Osawa, K. Terada, F. E. Brenker, B. J. Tkalcec, L. Vincze, R. Brunetto, A. Aléon-Toppani, Q. H. S. Chan, M. Roskosz, J.-C. Viennet, P. Beck, E. E. Alp, T. Michikami, Y. Nagaashi, T. Tsuji, Y. Ino, J. Martinez, J. Han, A. Dolocan, R. J. Bodnar, M. Tanaka, H. Yoshida, K. Sugiyama, A. J. King, K. Fukushi, H. Suga, S. Yamashita, T. Kawai, K. Inoue, A. Nakato, T. Noguchi, F. Vilas, A. R. Hendrix, C. Jaramillo-Correa, D. L. Domingue, G. Dominguez, Z. Gainsforth, C. Engrand, J. Duprat, S. S. Russell, E. Bonato, C. Ma, T. Kawamoto, T. Wada, S. Watanabe, R. Endo, S. Enju, L. Riu, S. Rubino, P. Tack, S. Takeshita, Y. Takeichi, A. Takeuchi, A. Takigawa, D. Takir, T. Tanigaki, A. Taniguchi, K. Tsukamoto, T. Yagi, S. Yamada, K. Yamamoto, Y. Yamashita, M. Yasutake, K. Uesugi, I. Umegaki, I. Chiu, T. Ishizaki, S. Okumura, E. Palomba, C. Pilorget, S. M. Potin, A. Alasli, S. Anada, Y. Araki, N. Sakatani, C. Schultz, O. Sekizawa, S. D. Sitzman, K. Sugiura, M. Sun, E. Dartois, E. De Pauw, Z. Dionnet, Z. Djouadi, G. Falkenberg, R. Fujita, T. Fukuma, I. R. Gearba, K. Hagiya, M. Y. Hu, T. Kato, T. Kawamura, M. Kimura, M. K. Kubo, F. Langenhorst, C. Lantz, B. Lavina, M. Lindner, J. Zhao, B. Vekemans, D. Baklouti, B. Bazi, F. Borondics, S. Nagasawa, G. Nishiyama, K. Nitta, J. Mathurin, T. Matsumoto, I. Mitsukawa, H. Miura, A. Miyake, Y. Miyake, H. Yurimoto, R. Okazaki, H. Yabuta, H. Naraoka, K. Sakamoto, S. Tachibana, H. C. Connolly, D. S. Lauretta, M. Yoshitake, M. Yoshikawa, K. Yoshikawa, K. Yoshihara, Y. Yokota, K. Yogata, H. Yano, Y. Yamamoto, D. Yamamoto, M. Yamada, T. Yamada, T. Yada, K. Wada, T. Usui, R. Tsukizaki, F. Terui, H. Takeuchi, Y. Takei, A. Iwamae, H. Soejima, K. Shirai, Y. Shimaki, H. Senshu, H. Sawada, T. Saiki, M. Ozaki, G. Ono, T. Okada, N. Ogawa, K. Ogawa, R. Noguchi, H. Noda, M. Nishimura, N. Namiki, S. Nakazawa, T. Morota, A. Miyazaki, A. Miura, Y. Mimasu, K. Matsumoto, K. Kumagai, T. Kouyama, S. Kikuchi, K. Kawahara, S. Kameda, T. Iwata, Y. Ishihara, M. Ishiguro, H. Ikeda, S. Hosoda, R. Honda, C. Honda, Y. Hitomi, N. Hirata, T. Hayashi, M. Hayakawa, K. Hatakeda, S. Furuya, R. Fukai, A. Fujii, Y. Cho, M. Arakawa, M. Abe, Y. Tsuda, Tohoku University [Sendai], NASA Johnson Space Center (JSC), NASA, The University of Tokyo (UTokyo), Tokyo Institute of Technology [Tokyo] (TITECH), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), Planetary Exploration Research Center [Chiba] (PERC), Chiba Institute of Technology (CIT), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Nagoya University, Department of Earth and Planetary Science [Tokyo], Graduate School of Science [Tokyo], The University of Tokyo (UTokyo)-The University of Tokyo (UTokyo), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Guangzhou Institute of Geochemistry, Ritsumeikan University, Japan Synchrotron Radiation Research Institute [Hyogo] (JASRI), Institute of Low Temperature Science [Sapporo], Hokkaido University [Sapporo, Japan], Department of Earth, Environmental and Planetary Sciences [Providence], Brown University, The University of Aizu, University of Washington [Seattle], Osaka University, Kavli Institute for the Physics and Mathematics of the Universe [Tokyo] (Kavli IPMU), The University of Tokyo Institutes for Advanced Study (UTIAS), Japan Atomic Energy Agency, Goethe-University Frankfurt am Main, Department of Inorganic and Physical Chemistry, Ghent University, Universiteit Gent = Ghent University (UGENT), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Earth Sciences, Royal Holloway, University of London, Egham, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Advanced Photon Source [ANL] (APS), Argonne National Laboratory [Lemont] (ANL)-University of Chicago-US Department of Energy, Kindai University, Kyushu University, Department of Earth and Atmospheric Sciences [Houston], University of Houston, Texas Materials Institute (TMI), University of Texas at Austin [Austin], Department of Geoscience, Virginia Tech, Blacksburg, VA, United States, National Institute for Materials Science (NIMS), Department of Earth Sciences [NHM London] (DES-NHM), The Natural History Museum [London] (NHM), Kanazawa University (KU), Graduate University for Advanced Studies [Hayama] (SOKENDAI), Division of Earth and Planetary Sciences [Kyoto], Kyoto University, Planetary Science Institute [Tucson] (PSI), Pennsylvania State University (Penn State), Penn State System, California State University [San Marcos] (CSUSM), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), University of Shizuoka, Ehime University [Matsuyama, Japon], European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), KEK (High energy accelerator research organization), Hitachi, Ltd, Institute for integrated Radiation and Nuclear Science (KURNS), National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Department of Physics, Rikkyo University, Tokyo, Japan Fine Ceramics Center (JFCC), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), The Aerospace Corporation, Earth-Life Science Institute [Tokyo] (ELSI), University of Chinese Academy of Sciences [Beijing] (UCAS), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Photone Sciences, Deutsches Elektronen-Synchrotron (DESY), Graduate School of Life Science, University of Hyogo, International Christian University, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Center for Advanced Radiation Sources [University of Chicago] (CARS), University of Chicago, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Physique (ICP), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Graduate School of Information Science [Nagoya], Department of Natural History Sciences, Department of Earth and Planetary Sciences [Fukuoka], Graduate School of Advanced Science and Engineering [Higashi-Hiroshima], Hiroshima University, Rowan University, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Kanagawa Institute of Technology, Marine Works Japan Ltd., Faculty of Science, Niigata University, National Astronomical Observatory of Japan (NAOJ), Department of Physics and Astronomy [Seoul], Seoul National University [Seoul] (SNU), Kochi University, Department of Planetology, Graduate School of Science, Graduate School of Science [Kobe], Kobe University-Kobe University, Kobe University, Supported by KAKENHI from the Japanese Society for Promotion of Science (JSPS), grants JP20H00188 and 19H05183 to T.N., JP19K14776 to M.M., 21K18645 to T.M. and K.S., JP20H00205 to A.Ts., M.M., A.M. and J.M., 17H06458 to K.F., Y.T., S.Y. and M.K., JP17H06459 to T.N., T.U., S.W., M.M., N.N., T.M., T.O., Y.S., N.S., and R.N., JP15H05695 to A.Ts. and K.U., 20H05846 to S.T., JP17H06457 to H.G., JP17H06458 to Y. T. and K. F., JP19H00726 to K.K., H. G., and T.M., JP21J13337 to K.A., and JP18H05456,JP20H00189 to K.S., 18H05463 to T.T., S.N., and S.W., 18H05460 to K.N. and T.O., 18H05464 to Y.M., 18H05457 to K.N., T.T., S.W., and Y.M., and JP18H05479 to M.U. Also supported by the JSPS Core-to-Core program ' International Network of Planetary Sciences', and from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (grants JPMXS0450200421 and JPMXS0450200521) to SS. A.K. acknowledges funding support from UK Research and Innovation (UKRI) grant MR/T020261/1. A.B. acknowledges funding support from NASA Emerging Worlds grant - 80NSSC18K0731. P.B. acknowledges funding from the European Research Council (ERC) under grant agreement no. 771691 (Solarys) and the CNES., and European Project: 771691,SOLARYS
Subjects: Multidisciplinary, [SDU]Sciences of the Universe [physics], Ryugu Hayabusa2 Carbonaceous asteroid Sample return
Abstract: Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of
Published: 2022
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2. Observations of Didymos: Past Results and Future Plans

Author: Thomas, C., Rivkin, Andrew S., Pravec, P., Scheirich, Peter, Carry, Benoît, de Léon, J., Green, S., Howell, Ellen S., Knight, M. M., Licandro, Javier, Moskovitz, Nicholas A., Osip, David J., Snodgrass, Colin, Thomas-Osip, Joanna E., Northern Arizona University, Flagstaff, Applied Physics Laboratory, Johns Hopkins University, Ondrejov Observatory, Charlottesville, VA, United States, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Instituto de Astrofísica de Canarias (IAC), Open University, Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona (LPL), University of Maryland [College Park], University of Maryland System, Lowell Observatory, Flagstaff, NRL, Washington, and Gemini Observatory, Southern Operations Center
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The binary near-Earth asteroid (65803) Didymos is the target for the two components of the Asteroid Impact and Deflection Assessment (AIDA) mission. The NASA DART (Double Asteroid Redirection Test) mission is scheduled to impact the Didymos secondary during its apparition in 2022. ESA's proposed Hera mission will arrive years later to obtain in situ observations of the system following the DART impact. One key scientific goal of AIDA is to measure and characterize the deflection caused by the impact. A combination of spacecraft and ground and space based optical and radar observations in 2022 will provide the required data for AIDA to meet its top-level mission goals.
Published: 2018

3. Parallaxes and infrared photometry of three Y0 dwarfs

Author: Richard L. Smart, Pascal Tremblin, Jane E. Morrison, David S. Amundsen, Federico Marocco, S. K. Leggett, D. J. Pinfield, J. Davy Kirkpatrick, Daniel Apai, Hugh R. A. Jones, ITA, USA, GBR, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Steward Observatory, University of Arizona, Lunar and Planetary Laboratory [University of Arizona] (LPL), Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy (AURA), School of Physics, Astronomy and Mathematics [Hatfield], University of Hertfordshire [Hatfield] (UH), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Exeter, European Project: 247593,EC:FP7:PEOPLE,FP7-PEOPLE-2009-IRSES,IPERCOOL(2010), Centre for Astrophysics Research [Hatfield], and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
Subjects: Absolute magnitude, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Metallicity, Infrared telescope, Brown dwarf, FOS: Physical sciences, Astrophysics, 01 natural sciences, Photometry (optics), Observatory, 0103 physical sciences, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Astronomy, Astronomy and Astrophysics, Astrometry, Effective temperature, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, parallaxes, astrometry, techniques: spectroscopic, brown dwarfs
Abstract: We have followed up the three Y0 dwarfs WISEPA J041022.71+150248.5, WISEPA J173835.53+273258.9 and WISEPC J205628.90+145953.3 using the UKIRT/WFCAM telescope/instruments. We find parallaxes that are more consistent and accurate than previously published values. We estimate absolute magnitudes in photometric pass-bands from $Y$ to $W3$ and find them to be consistent between the three Y0 dwarfs indicating the inherent cosmic absolute magnitude spread of these objects is small. We examine the MKO $J$ magnitudes over the four year time line and find small but significant monotonic variations. Finally we estimate physical parameters from a comparison of spectra and parallax to equilibrium and non-equilibrium models finding values consistent with solar metallicity, an effective temperature of 450-475\,K and log~g of 4.0-4.5., 12 Pages, 10 figures, Accepted by MNRAS
Published: 2017
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4. Titan's mid-latitude surface regions with Cassini VIMS and SAR

Author: Solomonidou, Anezina, Coustenis, Athéna, Drossart, Pierre, Brown, Robert H., Sohl, Frank, Stephan, Katrin, Jaumann, Ralf, Rodriguez, Sebastien, Bratsolis, Emmanuel, Schmitt, Bernard, Le Gall, Alice, Lopes, Rosaly M. C., Malaska, Michael J., Janssen, Michael A., Maltagliati, Luca, Villanueva, Edward, Matsoukas, Christos, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Physics [Athens], National and Kapodistrian University of Athens (NKUA), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Stockholm], Royal Institute of Technology [Stockholm] (KTH ), and Henry, Florence
Subjects: [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We investigate the surface of Saturn's moon Titan by means of two Cassini instruments used in synergy. We apply a radiative transfer code to VIMS hyperspectral data to correct the strong atmospheric contribution and extract information on surface composition (Hirtzig et al. 2014; Solomonidou et al. 2014; 2015). We then put this in the context of terrain morphology by use of denoised Synthetic Aperture Radar (SAR) images (Bratsolis et al. 2012). We examine here the mid-latitude zones extending from 50ºN to 50ºS, which includes key geological features identified in Lopes et al. (2010, 2015) and Malaska et al. (2015): mountains, plains, labyrinths, dune fields, and possible cryovolcanic and/or evaporitic deposits. We find that many of the different units show compositional variations while units of significant geomorphological differences seem to consist of very similar material mixtures. The Huygens landing site and the candidate evaporitic regions are compositionally similar to the variable plains. We also find that temporal variations of surface albedo exist for two of the candidate cryovolcanic regions Tui Regio and Sotra Patera, suggesting the presence of surface activity, while a number of other regions such as Hotei Regio and the undifferentiated plains remain unchanged (Solomonidou et al. 2015). The surface albedo variations, together with the presence of volcanic-like morphological features, suggest that the active regions are possibly related to the deep interior, possibly via cryovolcanic processes (with important implications for the satellite's astrobiological potential) as also indicated by recent interior structure models of Titan and corresponding calculations of the spatial pattern of maximum tidal stresses (Sohl et al. 2014). In previous studies (Lopes et al. 2015; Solomonidou et al. 2015) we showed that a variety of surface processes could be linked to the formation of the various geomorphological units (aeolian, fluvial, sedimentary, lacustrine) as well as the deposition of atmospheric products through the process of photolysis and sedimentation of organics. The surface albedo differences and similarities among the various geomorphological terrains constrain the implications for the geological processes that govern Titan's surface. [1] Bratsolis, E., et al.: PSS, 61, 108-113, 2012; [2] Hirtzig, M., et al.: Icarus, 226, 470-486, 2013; [3] Solomonidou, A., et al.: JGR, 119, 1729-1747, 2014; [4] Lopes, R.M.C., et al.: Icarus, 205, 540-558, 2010; [5] Lopes, R.M.C., et al.: Icarus, in press, 2015; [6] Malaska, M., et al.: Icarus, in press, 2015; [7] Solomonidou, A., et al.: Icarus, in press, 2015; [8] Sohl, F., et al.: JGR, 119, 1013-1036, 2014.
Published: 2016

5. Photometric changes on Saturn's Titan: Evidence for active cryovolcanism

Author: Dale P. Cruikshank, Angioletta Coradini, F. Leader, Pierre Drossart, Karl L. Mitchell, P. Cerroni, Robert M. Nelson, Randolph L. Kirk, Dennis L. Matson, Stephen D. Wall, Fabrizio Capaccioni, John C. Pearl, Kevin H. Baines, Vito Mennella, M. Combes, P. D. Nicholson, Gianrico Filacchione, M. D. Boryta, Ralf Jaumann, L. W. Kamp, Yves Langevin, Rosaly M. C. Lopes, Bruno Sicardy, Thomas B. McCord, Jonathan I. Lunine, Vittorio Formisano, Jean-Pierre Bibring, Roger N. Clark, Bruce Hapke, Patrick G. J. Irwin, Christophe Sotin, Giancarlo Bellucci, William D. Smythe, Jet Propulsion Laboratory, California Institute of Technology (JPL), US Geological Survey, Flagstaff, Department of Geology and Planetary Science, University of Pittsburgh, Department of Earth Science and Astronomy, Mt. San Antonio College, Walnut, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, United States Geological Survey, Denver, SETI Institute, NASA Ames Research Center, Moffett Field, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ISFI, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Bear Fight Center, Space Science Institute, Winthrop, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Department of Astronomy, Cornell University, Clarendon Laboratory, Department of Physics, University of Oxford, and NASA/Goddard Space Flight Center (NASA/GSFC)
Subjects: Synthetic aperture radar, Spectrometer, Infrared, cryovolcanism, law.invention, Astrobiology, Photometry, Orbiter, symbols.namesake, Geophysics, law, symbols, General Earth and Planetary Sciences, Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Geology, Remote sensing
Abstract: International audience; We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March 18, 2006. We previously reported spectrophotometric variability at another location (26°S, 78°W). Cassini Synthetic Aperture RADAR (SAR) images find that the surface morphology at both locations is consistent with surface flows possibly resulting from cryovolcanic activity (Wall et al., companion paper, this issue). The VIMS-reported time variability and SAR morphology results suggest that Titan currently exhibits intermittent surface changes consistent with present ongoing surface processes. We suggest that these processes involve material from Titan's interior being extruded or effused and deposited on the surface, as might be expected from cryovolcanism.
Published: 2016
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6. Results from the Huygens probe on Titan

Author: Athena Coustenis, Jonathan I. Lunine, Tobias Owen, Jean-Pierre Lebreton, François Raulin, Darrell F. Strobel, ESA-ESTEC, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institute for Astronomy, University of Hawaii, Johns Hopkins University, and Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA)
Subjects: Exploration of Saturn, Physics, Spacecraft, business.industry, Astronomy, Astronomy and Astrophysics, Space exploration, law.invention, Astrobiology, symbols.namesake, Orbiter, Planetary science, Space and Planetary Science, law, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Titan (rocket family)
Abstract: International audience; The Cassini-Huygens mission, comprising the NASA Saturn Orbiter and the ESA Huygens Probe, arrived at Saturn in late June 2004. The Huygens probe descended under parachute in Titan's atmosphere on 14 January 2005, 3 weeks after separation from the Orbiter. We discuss here the breakthroughs that the Huygens probe, in conjunction with the Cassini spacecraft, brought to Titan science. We review the achievements ESA's Huygens probe put forward and the context in which it operated. The findings include new localized information on several aspects of Titan science: the atmospheric structure and chemical composition; the aerosols distribution and content; the surface morphology and composition at the probe's landing site; the winds, the electrical properties, and the implications on the origin and evolution of the satellite.
Published: 2009
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7. Complex structure within Saturn’s infrared aurora

Author: Steve Miller, Emma J. Bunce, Bonnie J. Buratti, Robert H. Brown, Sarah V. Badman, Michele K. Dougherty, Christophe Sotin, Tom Stallard, Roger N. Clark, Chris S. Arridge, D. L. Talboys, Pierre Drossart, Phil D. Nicholson, Stan W. H. Cowley, Kevin H. Baines, Makenzie Lystrup, Nicholas Achilleos, Department of Physics and Astronomy, University of Leicester, University College of London [London] (UCL), Mullard Space Science Laboratory, Department of Space and Climate Physics, Imperial College London, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), US Geological Survey, Denver, Department of Astronomy, Cornell University, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Physics, Multidisciplinary, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, Astrophysics, Charged particle, Astrobiology, Atmosphere, Solar wind, Planet, Magnetosphere of Saturn, Saturn, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Planetary aurorae are generally produced by currents flowing between the planet's ionosphere and magnetosphere, which accelerate energetic charged particles that then hit the upper atmosphere. Recent models of Saturn's aurora predict only weak emission away from the main auroral oval. Stallard et al. now present Cassini infrared images taken from a novel angle, providing the first nightside auroral view. They reveal emissions both poleward and equatorward of the main oval. The polar emissions vary with time, and seem not to be linked with strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained by current models of Saturn's magnetosphere. The majority of planetary aurorae are produced by electrical currents flowing between the ionosphere and the magnetosphere which accelerate energetic charged particles that hit the upper atmosphere. At Saturn, these processes collisionally excite hydrogen, causing ultraviolet emission1,2,3,4,5,6,7,8, and ionize the hydrogen, leading to H3+ infrared emission9,10,11,12,13,14,15. Although the morphology of these aurorae is affected by changes in the solar wind6,11, the source of the currents which produce them is a matter of debate16,17. Recent models predict only weak emission away from the main auroral oval18. Here we report images that show emission both poleward and equatorward of the main oval (separated by a region of low emission). The extensive polar emission is highly variable with time, and disappears when the main oval has a spiral morphology; this suggests that although the polar emission may be associated with minor increases in the dynamic pressure from the solar wind, it is not directly linked to strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained using our current understanding of Saturn’s magnetosphere. The equatorward arc of emission exists only on the nightside of the planet, and arises from internal magnetospheric processes that are currently unknown.
Published: 2008
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8. Neutral Atmospheres

Author: Julianne I. Moses, Jacques Crovisier, I. Mueller-Wodarg, Darrell F. Strobel, Roger V. Yelle, Raymond G. Roble, Stephen W. Bougher, J. H. Waite, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Johns Hopkins University (JHU), Lunar and Planetary Institute, Houston, Southwest Research Institute, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, and High Altitude Observatory, National Center for Atmospheric Research
Subjects: Solar System, Spacecraft, business.industry, Aeronomy, Astronomy and Astrophysics, Forcing (mathematics), Astrobiology, symbols.namesake, Space and Planetary Science, Planet, Saturn, Physics::Space Physics, Thermal, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Titan (rocket family)
Abstract: International audience; This paper summarizes the understanding of aeronomy of neutral atmospheres in the solar system, discussing most planets as well as Saturn's moon Titan and comets. The thermal structure and energy balance is compared, highlighting the principal reasons for discrepancies amongst the atmospheres, a combination of atmospheric composition, heliocentric distance and other external energy sources not common to all. The composition of atmospheres is discussed in terms of vertical structure, chemistry and evolution. The final section compares dynamics in the upper atmospheres of most planets and highlights the importance of vertical dynamical coupling as well as magnetospheric forcing in auroral regions, where present. It is shown that a first order understanding of neutral atmospheres has emerged over the past decades, thanks to the combined effects of spacecraft and Earth-based observations as well as advances in theoretical modeling capabilities. Key gaps in our understanding are highlighted which ultimately call for a more comprehensive programme of observation and laboratory measurements.
Published: 2008
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9. Asteroid 2867 Steins

Author: Olivier Groussin, F. Colas, M. A. Barucci, Jorge Márcio Carvano, Sonia Fornasier, S. Larson, Y.-J. Choi, Stephen C. Lowry, Laurent Jorda, Brian D. Warner, Agnieszka Kryszczyńska, G. Faury, Paul R. Weissman, Mikko Kaasalainen, M. D. Hicks, I. Toth, Philippe Lamy, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Mathematics and Statistics, Rolf Nevanlinna Institute, University of Helsinki, School of Mathematics and Physics, Queen's University, Jet Propulsion Laboratory, California Institute of Technology (JPL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Observatório Nacional/MCTI, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Paris Cité (UPCité), Astronomical Observatory, Adam Mickiewicz University, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, and Palmer Divide Observatory, Colorado Springs
Subjects: Physics, Ecliptic coordinate system, 010504 meteorology & atmospheric sciences, Equator, Ecliptic, Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Flattening, law.invention, Telescope, Spitzer Space Telescope, Space and Planetary Science, Asteroid, law, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; Context: Asteroid 2867 Steins is the first target of the Rosetta space mission with a flyby scheduled in September 2008. Aims: An early physical characterization is needed to optimize the flyby parameters and the science operations, and to maximize the scientific return. The aim of this article is to characterize the shape and rotational state of this asteroid. Methods: We compile a set of 26 visible light curves whose phase angle coverage extends from 7.5° to 41.7°, and perform their simultaneous inversion relying on convex modeling. Results: The full three-dimensional solution for asteroid 2867 Steins is rather spherical with axial ratios a/b=1.17 and a/c=1.25. The rotational state is characterized by a sidereal period of 6.04681 ± 0.00002 h, and the pole direction defined by its ecliptic coordinates lambda ≈ 250° and beta ≈ - 89° has an uncertainty of about 5°. It is therefore almost exactly perpendicular to the ecliptic plane, and the viewing geometries are thus restricted to only ±20° about Steins' equator. Consequently, the shape model is not strongly constrained, and the polar flattening has an uncertainty of about 10%. Inversion is basically scale-free, and absolute scaling comes from a measurement of its thermal emission with the Spitzer Space Telescope (Lamy et al. 2008, A&A, 487, 1187), yielding overall dimensions of 5.73 ± 0.52, 4.95±0.45, and 4.58 ± 0.41 km.
Published: 2008
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10. Measurements of methane absorption by the descent imager/spectral radiometer (DISR) during its descent through Titan's atmosphere

Author: Martin G. Tomasko, S. Engel, Lyn R. Doose, Erich Karkoschka, Bruno Bézard, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Radiometer, Materials science, Spectrometer, Astronomy and Astrophysics, Atmospheric sciences, Methane, Spectral line, Computational physics, Atmosphere, symbols.namesake, chemistry.chemical_compound, Atmospheric radiative transfer codes, chemistry, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, Atmosphere of Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family)
Abstract: International audience; New low-temperature methane absorption coefficients pertinent to the Titan environment are presented as derived from the Huygens DISR spectral measurements combined with the in-situ measurements of the methane gas abundance profile measured by the Huygens Gas Chromatograph/Mass Spectrometer (GCMS). The visible and near-infrared spectrometers of the descent imager/spectral radiometer (DISR) instrument on the Huygens probe looked upward and downward covering wavelengths from 480 to 1620 nm at altitudes from 150 km to the surface during the descent to Titan's surface. The measurements at continuum wavelengths were used to determine the vertical distribution, single-scattering albedos, and phase functions of the aerosols. The gas chromatograph/mass spectrometer (GCMS) instrument on the probe measured the methane mixing ratio throughout the descent. The DISR measurements are the first direct measurements of the absorbing properties of methane gas made in the atmosphere of Titan at the pathlengths, pressures, and temperatures that occur there. Here we use the DISR spectral measurements to determine the relative methane absorptions at different wavelengths along the path from the probe to the sun throughout the descent. These transmissions as functions of methane path length are fit by exponential sums and used in a haze radiative transfer model to compare the results to the spectra measured by DISR. We also compare the recent laboratory measurements of methane absorption at low temperatures [Irwin et al., 2006. Improved near-infrared methane band models and k-distribution parameters from 2000 to 9500 cm -1 and implications for interpretation of outer planet spectra. Icarus 181, 309-319] with the DISR measurements. We find that the strong bands formed at low pressures on Titan act as if they have roughly half the absorption predicted by the laboratory measurements, while the weak absorption regions absorb considerably more than suggested by some extrapolations of warm measurements to the cold Titan temperatures. We give factors as a function of wavelength that can be used with the published methane coefficients between 830 and 1620 nm to give agreement with the DISR measurements. We also give exponential sum coefficients for methane absorptions that fit the DISR observations. We find the DISR observations of the weaker methane bands shortward of 830 nm agree with the methane coefficients given by Karkoschka [1994. Spectrophotometry of the jovian planets and Titan at 300- to 1000-nm wavelength: the methane spectrum. Icarus 111, 174-192]. Finally, we discuss the implications of our results for computations of methane absorption in the atmospheres of the outer planets.
Published: 2008
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11. Rain and hail can reach the surface of Titan

Author: S.D.B. Graves, Christopher P. McKay, Caitlin A. Griffith, M. Fulchignoni, Francesca Ferri, Space Science Division, NASA Ames Research, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Materials science, Drop (liquid), Evaporation, Analytical chemistry, Humidity, Astronomy and Astrophysics, Radius, Atmospheric sciences, Methane, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, Latent heat, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Saturation (chemistry), Titan (rocket family)
Abstract: International audience; We have calculated the condensation and evaporation of ternary CH 4-N 2-C 2H 6 liquid drops and solid CH 4 hail as they fall through Titan's lower atmosphere to determine the likelihood that precipitation reaches the ground. Assuming the humidity profile determined by the Huygens probe, binary liquid CH 4/N 2 condensate grows in the region from ˜8 to 15 km in Titan's atmosphere because the combined humidity of CH 4 and N 2 exceeds saturation. These drops evaporate below ˜8 km. We determine the fate of 10 mum seeds composed of ethane, which is expected to provide condensation sites. In addition, we study the fate of already formed raindrops with radii of 1-4.75 mm falling out of the growth region. High (50%) and low (0%) ethane relative humidities (RH) are considered in the calculation. We find that drops with radii ˜3 mm and smaller dropping from 8 km reach the ground in compositional equilibrium with the atmosphere in the high ethane RH case as a result of the stabilizing influence of the ethane, and evaporate in the atmosphere in the low ethane RH case. Large drops (>˜3 mm) reach the surface large and cold because the latent heat loss due to the evaporation of methane cools the drop and slows the evaporation rate. Pure methane hail hits the ground if its radius is initially more than 4 mm at 16 km above the surface and sublimates in the atmosphere if its radius is smaller.
Published: 2008
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12. Hydrocarbons on Saturn's satellites Iapetus and Phoebe

Author: Dale P. Cruikshank, Yvonne J. Pendleton, C. M. Dalle Ore, Bonnie J. Buratti, Robert H. Brown, Gianrico Filacchione, Fabrizio Capaccioni, Eric Wegryn, Giancarlo Bellucci, Vito Mennella, Priscilla Cerroni, Vittorio Formisano, P. D. Nicholson, Roger N. Clark, Pierre Drossart, M. Combes, T. C. Owen, Yves Langevin, Robert M. Nelson, T. B. McCord, Ralf Jaumann, Kevin H. Baines, Dennis L. Matson, Bruno Sicardy, Angioletta Coradini, Jean-Pierre Bibring, Christophe Sotin, SETI Institute, NASA Ames Research Center, Moffett Field, Search for Extraterrestrial Intelligence Institute (SETI), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jet Propulsion Laboratory, California Institute of Technology (JPL), US Geological Survey, Denver, Space Science Institute, Winthrop, Department of Astronomy, Cornell University, Institute for Astronomy, University of Hawaii, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Department of Planetary Exploration, DLR, Université de Nantes (UN), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC)
Subjects: spectroscopy, Solar System, Materials science, Iapetus, Astronomy and Astrophysics, organic chemistry, Astrobiology, Interstellar medium, Meteorite, Space and Planetary Science, Geometric albedo, Absorption band, Saturn, Circumstellar dust, satellites composition, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cosmic dust
Abstract: Material of low geometric albedo (pV⩽0.1pV⩽0.1) is found on many objects in the outer Solar System, but its distribution in the saturnian satellite system is of special interest because of its juxtaposition with high-albedo ice. In the absence of clear, diagnostic spectral features, the composition of this low-albedo (or “dark”) material is generally inferred to be carbon-rich, but the form(s) of the carbon is unknown. Near-infrared spectra of the low-albedo hemisphere of Saturn's satellite Iapetus were obtained with the Visible–Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft at the fly-by of that satellite of 31 December 2004, yielding a maximum spatial resolution on the satellite's surface of ∼65 km. The spectral region 3–3.6 μm reveals a broad absorption band, centered at 3.29 μm, and concentrated in a region comprising about 15% of the low-albedo surface area. This is identified as the CH stretching mode vibration in polycyclic aromatic hydrocarbon (PAH) molecules. Two weaker bands attributed to CH2 stretching modes in aliphatic hydrocarbons are found in association with the aromatic band. The bands most likely arise from aromatic and aliphatic units in complex macromolecular carbonaceous material with a kerogen- or coal-like structure, similar to that in carbonaceous meteorites. VIMS spectra of Phoebe, encountered by Cassini on 11 June 2004, also show the aromatic hydrocarbon band, although somewhat weaker than on Iapetus. The origin of the PAH molecular material on these two satellites is unknown, but PAHs are found in carbonaceous meteorites, cometary dust particles, circumstellar dust, and interstellar dust.
Published: 2008
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13. Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper

Author: G. Boubin, Michael Allison, Ellen R. Stofan, Charles Elachi, G. Hamilton, Steven J. Ostro, L. Roth, Randolph L. Kirk, William T. K. Johnson, Stephen D. Wall, Y. Anderson, S. Shaffer, Roberto Seu, Philip S. Callahan, Lauren Wye, R. Boehmer, Bryan Stiles, Gian Gabriele Ori, Jani Radebaugh, Karl L. Mitchell, Giovanni Picardi, Howard A. Zebker, Laurence A. Soderblom, Duane O. Muhleman, Richard West, S. Vetrella, Enrico Flamini, R. D. Lorenz, Roberto Orosei, Andrew Dominic Fortes, Jonathan I. Lunine, Yonggyu Gim, K. Kelleher, L. E. Robshaw, Catherine D. Neish, E. Reffet, Pierre Encrenaz, Scott Hensley, Flora Paganelli, Michael Janssen, Rosaly M. C. Lopes, Francesco Posa, Charles A. Wood, G. Francescetti, Jet Propulsion Laboratory, California Institute of Technology (JPL), Proxemy Research, Bowie, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), US Geological Survey, Flagstaff, Wheeling Jesuit University, Environmental Sciences Department, Lancaster University, University College of London [London] (UCL), Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Agenzia Spaziale Italiana (ASI), Facoltá di Ingegneria, Geological and Planetary Sciences, California Institute of Technology, Pasadena, International Research School of Planetary Sciences, Dipartimento di Scienze, Università d'Annunzio, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Universitá La Sapienza, INFM and Dipartimento Interateneo di Fisica, and Stanford University
Subjects: Synthetic aperture radar, Solar System, geography, satellites of saturn, titan, volcanism, geography.geographical_feature_category, biology, Lava, Astronomy and Astrophysics, Venus, biology.organism_classification, Astrobiology, law.invention, symbols.namesake, Volcano, Space and Planetary Science, law, Radar imaging, symbols, Radar, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Geology
Abstract: International audience; The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic features identified from SAR images, their possible origin, and their geologic context. The features which we identify as cryovolcanic in origin include a large (180 km diameter) volcanic construct (dome or shield), several extensive flows, and three calderas which appear to be the source of flows. The composition of the cryomagma on Titan is still unknown, but constraints on rheological properties can be estimated using flow thickness. Rheological properties of one flow were estimated and appear inconsistent with ammonia-water slurries, and possibly more consistent with ammonia-water-methanol slurries. The extent of cryovolcanism on Titan is still not known, as only a small fraction of the surface has been imaged at sufficient resolution. Energetic considerations suggest that cryovolcanism may have been a dominant process in the resurfacing of Titan.
Published: 2007
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14. Spectral and morphological properties of various geological types of Titan's surface with Cassini VIMS and RADAR

Author: Solomonidou, Anezina, Coustenis, Athéna, Lopes, Rosaly M. C., Hirtzig, Mathieu, Rodriguez, Sebastien, Malaska, Michael J., Drossart, Pierre, Sotin, Christophe, Bratsolis, Emmanuel, Matsoukas, Christos, Brown, Robert, Maltagliati, Luca, NASA Jet Propulsion Laboratory, California Institute of Technology, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), National and Kapodistrian University of Athens (NKUA), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, and Henry, Florence
Subjects: [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Cassini's VIMS and the RADAR have been investigating Titan's surface since 2004. Both instruments unveiled the dynamic and complex surface expressions of this Saturnian moon, suggesting exogenic and endogenic processes [1;2;3]. In order to evaluate the atmospheric contribution and thereafter extract surface information, a Radiative transfer code is used to analyse different regions and to monitor their spectral behaviour over time [4;5;7]. We furthermore use RADAR despeckled SAR images to infer information on the morphology [6]. We find that temporal variations of surface albedo occur for some areas, but that their origin may differ from one region to the other. Tui Regio and Sotra Patera change with time becoming darker and brighter respectively in terms of surface albedo. In contrast, we find that the undifferentiated plains and the suggested evaporitic areas in the equatorial regions do not present any significant change [5]. This observation supports the hypothesis that Titan is surface brightening of Sotra supports a possible internal rather than an exogenic origin. This observation supports the hypothesis that Titan is a cryovolcanic world due to the presence of local complex volcanic-like geomorphology [1] and indications of surface albedo changes [4,5]. Potential sources of the energy for cryovolcanism include tidal heating, possible internal convection, and ice tectonics, is believed to be a pre-requisite of a habitable planetary body as it allows the recycling of minerals and potential nutrients and provides localized energy sources. A recent study has shown that tidal forces are a constant and significant source of internal deformation on Titan and the interior liquid water ocean can be relatively warm for reasonable amounts of ammonia concentrations [8].[1] Lopes, R.M.C., et al. JGR, 118, 2013 [2] Solomonidou, A., et al. PSS, 70, 2013 [3] Moore, J.M. GRL, 37, 2010 [4] Solomonidou, A., et al. JGR, 119, 2014 [5] Solomonidou, A., et al. submitted [6] Bratsolis, E., et al. PSS, 61, 2012 [7] Hirtzig, M., et al. Icarus, 226, 2013 [8] Sohl, F., et al. JGR, 119, 2014.
Published: 2015

15. On the discovery of CO nighttime emissions on Titan by Cassini/VIMS: Derived stratospheric abundances and geological implications

Author: Kevin H. Baines, Bonnie J. Buratti, Miguel Lopez-Valverde, Robert H. Brown, Philip D. Nicholson, Thomas W. Momary, Roger N. Clark, Sushil K. Atreya, Christophe Sotin, Pierre Drossart, Jet Propulsion Laboratory, California Institute of Technology (JPL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, US Geological Survey, Denver, and Department of Astronomy, Cornell University
Subjects: Physics, 010504 meteorology & atmospheric sciences, Airglow, Astronomy and Astrophysics, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Atmosphere, symbols.namesake, 13. Climate action, Space and Planetary Science, Stratopause, Atmospheric chemistry, 0103 physical sciences, Mixing ratio, symbols, Atmosphere of Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), 010303 astronomy & astrophysics, Stratosphere, 0105 earth and related environmental sciences
Abstract: International audience; We present a quantitative analysis of CO thermal emissions discovered on the nightside of Titan by Baines et al. [2005. The atmospheres of Saturn and Titan in the near-infrared: First results of Cassini/VIMS. Earth, Moon, and Planets, 96, 119-147]. in Cassini/VIMS spectral imagery. We identify these emission features as the P and R branches of the 1-0 vibrational band of carbon monoxide (CO) near 4.65 mum. For CH 3D, the prominent Q branch of the nu 2 fundamental band of CH 3D near 4.55 mum is apparent. CO 2 emissions from the strong v3 vibrational band are virtually absent, indicating a CO 2 abundance several orders of magnitude less than CO, in agreement with previous investigations. Analysis of CO emission spectra obtained over a variety of altitudes on Titan's nightside limb indicates that the stratospheric abundance of CO is 32±15 ppm, and together with other recent determinations, suggests a vertical distribution of CO nearly constant at this value from the surface throughout the troposphere to at least the stratopause near 300 km altitude. The corresponding total atmospheric content of CO in Titan is ˜2.9±1.5×10 14 kg. Given the long lifetime of CO in the oxygen-poor Titan atmosphere (˜0.5-1.0 Gyr), we find a mean CO atmospheric production rate of 6±3×10 5 kg yr -1. Given the lack of primordial heavy noble gases observed by Huygens [Niemann et al., 2005. The abundances of constituents of Titan's atmosphere from the GCMS on the Huygens probe. Nature, 438, 779-784], the primary source of atmospheric CO is likely surface emissions. The implied CO/CH 4 mixing ratio of near-surface material is 1.8±0.9×10 -4, based on an average methane surface emission rate over the past 0.5 Gyr of 1.3×10 -13 gm cm -2 s -1 as required to balance hydrocarbon haze production via methane photolysis [Wilson and Atreya, 2004. Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere. J. Geophys. Res. 109, E06002 Doi:10.1029/2003JE002181]. This low CO/CH 4 ratio is much lower than expected for the sub-nebular formation region of Titan and supports the hypothesis [e.g., Atreya et al., 2005. Methane on Titan: photochemical-meteorological-hydrogeochemical cycle. Bull. Am. Astron. Soc. 37, 735] that the conversion of primordial CO and other carbon-bearing materials into CH 4-enriched clathrate-hydrates occurs within the deep interior of Titan via the release of hydrogen through the serpentinization process followed by Fischer-Tropsch catalysis. The time-averaged predicted emission rate of methane-rich surface materials is ˜0.02 km 3 yr -1, a value significantly lower than the rate of silicate lava production for the Earth and Venus, but nonetheless indicative of significant active geological processes reshaping the surface of Titan.
Published: 2006
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16. The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes

Author: Howard A. Zebker, L. Roth, Ralph D. Lorenz, Bryan Stiles, Charles Elachi, Y. Anderson, Ellen R. Stofan, Roberto Seu, K. Kelleher, Giovanni Picardi, Gian Gabriele Ori, K. L. Mitchell, E. Reffet, Duane O. Muhleman, Jonathan I. Lunine, Jani Radebaugh, Enrico Flamini, G. Boubin, Yonggyu Gim, Lauren Wye, S. D. Wall, G. Francescetti, Robert West, Matthew A. Allison, S. Vetrella, Rosaly M. C. Lopes, G. Hamilton, Philip S. Callahan, Laurence A. Soderblom, R. Boehmer, S. Shaffer, Steven J. Ostro, Randolph L. Kirk, Pierre Encrenaz, Scott Hensley, M. A. Janssen, Flora Paganelli, William L. Johnson, Francesco Posa, Charles A. Wood, R. D., Lorenz, S., Wall, J., Radebaugh, G., Boubin, E., Reffet, M., Janssen, E., Stofan, R., Lope, R., Kirk, C., Elachi, J., Lunine, K., Mitchell, F., Paganelli, L., Soderblom, C., Wood, L., Wye, H., Zebker, Y., Anderson, S., Ostro, M., Allison, R., Boehmer, P., Callahan, P., Encrenaz, G. G., Ori, Franceschetti, Giorgio, Y., Gim, G., Hamilton, S., Hensley, W., Johnson, K., Kelleher, D., Muhleman, G., Picardi, F., Posa, L., Roth, R., Seu, S., Shaffer, B., Stile, Vetrella, Sergio, E., Flamini, R., West, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Proxemy Research, Bowie, US Geological Survey, Flagstaff, Planetary Science Institute, Tucson, AZ 85719, USA and Wheeling Jesuit College, Wheeling, Stanford University, Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), International Research School of Planetary Sciences, Dipartimento di Scienze, Università d'Annunzio, Facoltá di Ingegneria, Geological and Planetary Sciences, California Institute of Technology, Pasadena, Universitá La Sapienza, Istituto Nazionale per la Fisica della Materia (INFM) and Dip. Interateneo di Fisica, and Agenzia Spaziale Italiana (ASI)
Subjects: Geologic Sediments, Radar, Multidisciplinary, Extraterrestrial Environment, Titan moon, Wind, Hydrocarbons, Radar observations, Radar imaging, Wavelength, symbols.namesake, Saturn, Surface winds, symbols, Cassini, Particle Size, Spacecraft, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Methane, Geomorphology, Geology, Remote sensing
Abstract: The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.
Published: 2006
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17. Photometric survey of binary near-Earth asteroids

Author: J. Zhu, Z. Krzeminski, Štefan Gajdoš, Michael D. Hicks, A. Klotz, B. L. Knight, R. R. Dyvig, Peter Brown, M. Grenon, Yu. N. Krugly, Robert D. Stephens, Walter R. Cooney, Y. Revaz, Jozef Vilagi, P. Scheirich, A. Grauer, Raoul Behrend, Franck Marchis, Lenka Šarounová, Peter Kusnirak, Stefano Mottola, Robert J. Whiteley, Gianluca Masi, G. Burki, Alan W. Harris, Ellen S. Howell, V. Cotrez, C. Demeautis, Jean-Luc Margot, Petr Pravec, N. Waelchli, David J. Tholen, Stephen Larson, Donald P. Pray, Vishnu Reddy, L. Brunetto, S. Moore, P. Thierry, D. Matter, Michael C. Nolan, G. Esquerdo, K. Kirsch, G. M. Funkhouser, G. Kober, G. Hahn, W. Holliday, Brian D. Warner, D. R. Degraff, F. P. Velichko, Adrian Galad, David Higgins, M. Rieugné, Lance A. M. Benner, L. Snyder, R. Roy, S. M. Slivan, N. Kaiser, Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Czech Academy of Sciences [Prague] (CAS), DLR Institute of Planetary Research, Rutherfordstr. 2, D-12489 Berlin, Germany, Department of Physics and Astronomy, University of Western Ontario, Carbuncle Hill Observatory, Palmer Divide Observatory, Colorado Springs, Space Science Institute, La Canada, National Astronomy and Ionosphere Center / Arecibo Observatory, HC3 Box 53995, Arecibo (NAIC), Jet Propulsion Laboratory, California Institute of Technology (JPL), Department of Astronomy, Cornell University, Ithaca, NY 14853, USA, Modra Observatory, Department of Astronomy, Physics of the Earth and Meteorology, River Oaks Observatory, 1125 Isaac Creek Circle, New Braunfels, TX 78132, USA, Institute of Astronomy [Kharkiv], V.N. Karazin Kharkiv National University (KhNU), Institute for Astronomy, University of Hawaii, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Department of Astronomy, University of California, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Alfred University, Department of Physics and Astronomy, University of Arkansas, United States Naval Observatory (USNO), Beijing Astronomical Observatory, Chinese Academy of Sciences, Badlands Observatory, Keck Observatoires, University of North Dakota, Astronomy Department, California Institute of Technology, Pasadena, Università degli Studi di Roma Tor Vergata [Roma], Campo Catino Observatory, Hunters Hill Observatory, Department of Astronomy, Whitin Observatory, Wellesley College, Observatoire de Genève, Observatoire de Blauvac, 138 Village-Neuf, F.-X. Bagnoud Observatory, CH-3961 St-Luc, Switzerland, Observatoire d'astronomie de Saint-Caprais, Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Le Cres Observatory, and Observatoire N°139 d'Antibes
Subjects: Physics, Angular momentum, education.field_of_study, Near-Earth object, photometry, Population, binary, Astronomy, Astronomy and Astrophysics, Asteroids, Space and Planetary Science, Asteroid, Total angular momentum quantum number, Roche limit, Orbital motion, Terrestrial planet, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], education
Abstract: Photometric data on 17 binary near-Earth asteroids (15 of them are certain detections, two are probables) were analysed and characteristic properties of the near-Earth asteroid (NEA) binary population were inferred. We have found that binary systems with a secondary-to-primary mean diameter ratio D s / D p ⩾ 0.18 concentrate among NEAs smaller than 2 km in diameter; the abundance of such binaries decreases significantly among larger NEAs. Secondaries show an upper size limit of D s = 0.5 – 1 km . Systems with D s / D p ⩽ 0.5 are abundant but larger satellites are significantly less common. Primaries have spheroidal shapes and they rotate rapidly, with periods concentrating between 2.2 to 2.8 h and with a tail of the distribution up to ∼4 h. The fast rotators are close to the critical spin for rubble piles with bulk densities about 2 g/cm3. Orbital periods show an apparent cut-off at P orb ∼ 11 h ; closer systems with shorter orbital periods have not been discovered, which is consistent with the Roche limit for strengthless bodies. Secondaries are more elongated on average than primaries. Most, but not all, of their rotations appear to be synchronized with the orbital motion; nonsynchronous secondary rotations may occur especially among wider systems with P orb > 20 h. The specific total angular momentum of most of the binary systems is similar to within ±20% and close to the angular momentum of a sphere with the same total mass and density, rotating at the disruption limit; this suggests that the binaries were created by mechanism(s) related to rotation near the critical limit and that they neither gained nor lost significant amounts of angular momentum during or since formation. A comparison with six small asynchronous binaries detected in the main belt of asteroids suggests that the population extends beyond the region of terrestrial planets, but with characteristics shifted to larger sizes and longer periods. The estimated mean proportion of binaries with D s / D p ⩾ 0.18 among NEAs larger than 0.3 km is 15 ± 4 % . Among fastest rotating NEAs larger than 0.3 km with periods between 2.2 and 2.8 h, the mean proportion of such binaries is (66+10−12)%.
Published: 2006
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18. Meridional variations of temperature, C2H2 and C2H6 abundances in Saturn's stratosphere at southern summer solstice

Author: Julianne I. Moses, Matthew J. Richter, Thomas K. Greathouse, Bruno Bézard, Caitlin A. Griffith, John H. Lacy, Lunar and Planetary Institute, Houston, Department of Astronomy, University of Texas, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, University of California [Davis] (UC Davis), and University of California (UC)
Subjects: Atmosphere, Space and Planetary Science, Saturn, Equator, Mixing ratio, Solstice, Environmental science, Astronomy and Astrophysics, Zonal and meridional, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Atmospheric sciences, Stratosphere, Latitude
Abstract: International audience; Measurements of the vertical and latitudinal variations of temperature and C 2H 2 and C 2H 6 abundances in the stratosphere of Saturn can be used as stringent constraints on seasonal climate models, photochemical models, and dynamics. The summertime photochemical loss timescale for C 2H 6 in Saturn's middle and lower stratosphere ( ˜40-10,000 years, depending on altitude and latitude) is much greater than the atmospheric transport timescale; ethane observations may therefore be used to trace stratospheric dynamics. The shorter chemical lifetime for C 2H 2 ( ˜1-7 years depending on altitude and latitude) makes the acetylene abundance less sensitive to transport effects and more sensitive to insolation and seasonal effects. To obtain information on the temperature and hydrocarbon abundance distributions in Saturn's stratosphere, high-resolution spectral observations were obtained on September 13-14, 2002 UT at NASA's IRTF using the mid-infrared TEXES grating spectrograph. At the time of the observations, Saturn was at a L≈270°, corresponding to Saturn's southern summer solstice. The observed spectra exhibit a strong increase in the strength of methane emission at 1230 cm -1 with increasing southern latitude. Line-by-line radiative transfer calculations indicate that a temperature increase in the stratosphere of ≈10 K from the equator to the south pole between 10 and 0.01 mbar is implied. Similar observations of acetylene and ethane were also recorded. We find the 1.16 mbar mixing ratio of C 2H 2 at -1° and -83° planetocentric latitude to be 9.2-3.8+6.4×10 and 2.5-1.0+1.8×10, respectively. The C 2H 2 mixing ratio at 0.12 mbar is found to be 1.0-0.3+0.5×10 at -1° planetocentric latitude and 2.6-0.9+1.3×10 at -83° planetocentric latitude. The 2.3 mbar mixing ratio of C 2H 6 inferred from the data is 7.5-1.7+2.3×10 and 1.0-0.2+0.3×10 at -1° and -83° planetocentric latitude, respectively. Further observations, creating a time baseline, will be required to completely resolve the question of how much the latitudinal variations of C 2H 2 and C 2H 6 are affected by seasonal forcing and/or stratospheric circulation.
Published: 2005
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19. Radar: The Cassini Titan Radar Mapper

Author: Steven J. Ostro, Randolph L. Kirk, Laurence A. Soderblom, L. Borgarelli, Giovanni Picardi, M. A. Janssen, Duane O. Muhleman, Pierre Encrenaz, Francesco Posa, L.E. Roth, Charles A. Wood, Chris Rapley, Michael Allison, Ralph D. Lorenz, Jonathan I. Lunine, William T. K. Johnson, Charles Elachi, Howard A. Zebker, Eastwood Im, Roberto Seu, S. Vetrella, S. D. Wall, C., Elachi, M. D., Allison, L., Borgarelli, E., Encrenaz, E., Im, M. A., Janssen, W. T. K., Johnson, R. L., Kirk, R. D., Lorenz, J. I., Lunine, D. O., Muhleman, S. J., Ostro, G., Picardi, F., Posa, C. G., Rapley, L. E., Roth, R., Seu, L. A., Soderblom, Vetrella, Sergio, S. D., Wall, C. A., Wood, H. A., Zebker, Jet Propulsion Laboratory, California Institute of Technology (JPL), Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Alenia Aerospazio, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), US Geological Survey, Flagstaff, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Geological and Planetary Sciences, California Institute of Technology, Pasadena, Universitá La Sapienza, Dipartimento Interateneo di Fisica, Politecnico di Bari, British Antarctic Survey, Natural Environment Research Council, Facoltá di Ingegneria, University of North Dakota, and Stanford University
Subjects: Radar altimeter, Titan moon, Astronomy and Astrophysics, Scatterometer, Space-based radar, law.invention, Radar engineering details, Radar astronomy, Space and Planetary Science, law, Radar imaging, 3D radar, Cassini, Radar, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Remote sensing
Abstract: International audience; The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will provide information on relative elevations in selected areas. Surfaces of the Saturn's icy satellites will be explored utilizing the RADAR radiometer and scatterometer modes. Saturn's atmosphere and rings will be probed in the radiometer mode only. The instrument is a joint development by JPL/NASA and ASI. The RADAR design features significant autonomy and data compression capabilities. It is expected that the instrument will detect surfaces with backscatter coefficient as low as -40 dB.
Published: 2004
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20. Meridional transport of HCN from SL9 impacts on Jupiter

Author: Matthew J. Richter, John H. Lacy, Caitlin A. Griffith, Douglas M. Kelly, Thomas K. Greathouse, Bruno Bézard, Emmanuel Lellouch, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Astronomy, University of Texas, Steward Observatory, University of Arizona, Department of Physics and Astronomy [Univ California Davis] (Physics - UC Davis), University of California [Davis] (UC Davis), and University of California (UC)-University of California (UC)
Subjects: Atmosphere, Jupiter, Space and Planetary Science, Equator, Northern Hemisphere, Environmental science, Astronomy and Astrophysics, Zonal and meridional, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Atmospheric sciences, Stratosphere, Jovian, Latitude
Abstract: International audience; In July 1994, the Shoemaker-Levy 9 (SL9) impacts introduced hydrogen cyanide (HCN) to Jupiter at a well confined latitude band around -44°, over a range of specific longitudes corresponding to each of the 21 fragments (Bézard et al. 1997, Icarus 125, 94-120). This newcomer to Jupiter's stratosphere traces jovian dynamics. HCN rapidly mixed with longitude, so that observations recorded later than several months after impact witnessed primarily the meridional transport of HCN north and south of the impact latitude band. We report spatially resolved spectroscopy of HCN emission 10 months and 6 years following the impacts. We detect a total mass of HCN in Jupiter's stratosphere of 1.5±0.7×10 13 g in 1995 and 1.7±0.4×10 13 g in 2000, comparable to that observed several days following the impacts (Bézard et al. 1997, Icarus 125, 94-120). In 1995, 10 months after impact, HCN spread to -30° and -65° latitude (half column masses), consistent with a horizontal eddy diffusion coefficient of Kyy=2-3×10 10 cm 2 s -1. Six years following impact HCN is observed in the northern hemisphere, while still being concentrated at 44° south latitude. Our meridional distribution of HCN suggests that mixing occurred rapidly north of the equator, with Kyy=2-5×10 11 cm 2 s -1, consistent with the findings of Moreno et al. (2003, Planet. Space Sci. 51, 591-611) and Lellouch et al. (2002, Icarus 159, 112-131). These inferred eddy diffusion coefficients for Jupiter's stratosphere at 0.1-0.5 mbar generally exceed those that characterize transport on Earth. The low abundance of HCN detected at high latitudes suggests that, like on Earth, polar regions are dynamically isolated from lower latitudes.
Published: 2004
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21. Looking at some equatorial regions on Titan using Cassini/VIMS and RADAR data: a case for changes in surface properties

Author: Solomonidou, Anezina, Coustenis, Athéna, Lopes, Rosaly M. C., Hirtzig, Mathieu, Bratsolis, Emmanuel, Drossart, Pierre, Le Mouélic, Stéphane, Rodriguez, Sebastien, Jaumann, Ralf, Stephan, Katrin, Bampasidis, Georgios, Sotin, Christophe, Brown, Robert, Henry, Florence, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Jet Propulsion Laboratory, California Institute of Technology (JPL), Fondation La main à la pâte, National and Kapodistrian University of Athens (NKUA), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institute of Planetary Research, DLR, Rutherfordstrasse 2, D-12489 Berlin, Germany, Deutsches Zentrum für Luft- und Raumfahrt (DLR), and Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona (LPL)
Subjects: Planetengeologie, Cassini / VIMS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Titan, Saturn's largest moon, has a complex, dynamic and -in some aspects- Earth-like atmosphere and surface. Data from the remote sensing instruments on board Cassini, particularly VIMS and the RADAR, have shown the presence of diverse terrains on the surface, suggesting exogenic and endogenic processes [1;2;3]. In this research we focus on some equatorial regions that have been identified as possibly subject to changes, having particular spectral properties and possibly being the strongest cryovolcanic candidate regions, that is: Sotra Patera, Hotei Regio and Tui Regio [1,4,5]. We use VIMS data, to which we apply a state-of-the-art Principal Component Analysis (PCA) and radiative transfer methods [4;7] with updated parameterization for the spectroscopic data and infer the surface albedos of all of these regions, that we interpret in terms of possible surface composition and morphology combining with information from RADAR data. Indeed, by including despeckled SAR images we identify geomorphological units and investigate spatial and temporal geological relationships [6]. This combination provides us with implications on the surface composition of different units. By looking at evolution with time, we find that two of these regions show albedo changes with time, for Tui Regio from 2005-2009 (darkening) and Sotra Patera from 2005-2006 (brightening) at all wavelengths, indicating that dynamical processes control the regions, compatible with their complex morphology. In conclusion, we also associate radiometry and topographic data with the compositional information from VIMS to derive constraints on the chemical composition and the geology of the surface and finally the nature of these regions. References: [1] Lopes, R.M.C., et al.: JGR, 118, 416-435; [2] Solomonidou, A., et al.: PSS, 70, 77-104; [3] Moore, J.M., and Howard, A.D.: GRL, 37, L22205, 2010; [4] Solomonidou, A., et al.: submitted(a); [5] Solomonidou, A., et al.: submitted(b); [6] Bratsolis, E., et al.: PSS, 61, 108-113; [7] Hirtzig, M., et al.: Icarus, 226, 470-486.
Published: 2014

22. Ground-based Near-infrared Emission Spectroscopy of HD 189733b

Author: Mark R. Swain, Pieter Deroo, Giovanna Tinetti, Pierre Drossart, Ingo Waldmann, Caitlin A. Griffith, University College of London [London] (UCL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Haute résolution angulaire en astrophysique, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Pôle Planétologie du LESIA, Jet Propulsion Laboratory, California Institute of Technology (JPL), Lunar and Planetary Laboratory [University of Arizona] (LPL), and University of Arizona
Subjects: Physics, L band, Space and Planetary Science, Conjunction (astronomy), Astronomy and Astrophysics, Astrophysics, Emission spectrum, Spectral resolution, Spectroscopy, Energy source, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Vibrational temperature, Eclipse
Abstract: International audience; We investigate the K- and L-band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA Infrared Telescope Facility. The observations for each of these three nights use equivalent instrument settings and the data from one of the nights have previously been reported by Swain et al. We describe an improved data analysis method that, in conjunction with the multi-night data set, allows increased spectral resolution (R ~ 175) leading to high-confidence identification of spectral features. We confirm the previously reported strong emission at ~3.3 mum and, by assuming a 5% vibrational temperature excess for methane, we show that non-LTE emission from the methane nu3 branch is a physically plausible source of this emission. We consider two possible energy sources that could power non-LTE emission and additional modeling is needed to obtain a detailed understanding of the physics of the emission mechanism. The validity of the data analysis method and the presence of strong 3.3 mum emission are independently confirmed by simultaneous, long-slit, L-band spectroscopy of HD 189733b and a comparison star.
Published: 2012
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23. Asteroid (101955) 1999 RQ36: Spectroscopy from 0.4 to 2.4 mum and meteorite analogs

Author: Edward A. Cloutis, Alicia M. Soderberg, Maria Antonietta Barucci, Dante S. Lauretta, Ellen S. Howell, Philip R. Christensen, Beth E. Clark, F. DeMeo, Richard P. Binzel, M. Ockert-Bell, Harold C. Connolly, Carl Hergenrother, Josh Emery, Michael Mueller, Lucy F. Lim, Department of Physics, Ithaca College, Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Arecibo Observatory, Department of Geography, University of Winnipeg, Arizona State University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Guest observer at NASA Infrared Telescope Facility, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Earth and Planetary Sciences, City University of New York, Department of Astronomy, Harvard University, Deutsches Geodätisches Forschungsinstitut (DGFI), Department of Earth and Planetary Science, University of Tennessee, Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Meteorite, Space and Planetary Science, Infrared, Asteroid, Chondrite, Carbonaceous chondrite, Astronomy, Astronomy and Astrophysics, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectrograph, Spectral line
Abstract: International audience; We present reflectance spectra from 0.4 to 2.4 mum of Asteroid (101955) 1999 RQ36, the target of the OSIRIS-REx spacecraft mission. The visible spectral data were obtained at the McDonald Observatory 2.1-m telescope with the ES2 spectrograph. The infrared spectral data were obtained at the NASA Infrared Telescope Facility using the SpeX instrument. The average visible spectrum is combined with the average near-infrared wavelength spectrum to form a composite spectrum. We use three methods to constrain the compositional information in the composite spectrum of Asteroid (101955) 1999 RQ36 (hereafter RQ36). First, we perform a least-squares search for meteorite spectral analogs using 15,000 spectra from the RELAB database. Three most likely meteorite analogs are proposed based on the least-squares search. Next, six spectral parameters are measured for RQ36 and their values are compared with the ranges in parameter values of the carbonaceous chondrite meteorite classes. A most likely meteorite analog group is proposed based on the depth of overlap in parameter values. The results of the least-squares search and the parametric comparisons point to CIs and/or CMs as the most likely meteorite analogs for RQ36, and COs and CHs as the least likely. RQ36 has a spectrally "blue" continuum slope that is also observed in carbonaceous chondrites containing magnetite. We speculate that RQ36 is composed of a "CM1"-like material. Finally, we compare RQ36 to other B-type asteroids measured by Clark et al. (Clark, B.E. et al. [2010]. J. Geophys. Res. 115, E06005). The results of this comparison are inconclusive. RQ36 is comparable to Themis spectral properties in terms of its albedo, visible spectrum, and near-infrared spectrum from 1.1 to 1.45 mum. However, RQ36 is more similar to Pallas in terms of its near-infrared spectrum from 1.6 to 2.3 mum. Thus it is possible that B-type asteroids form a spectral continuum and that RQ36 is a transitional object, spectrally intermediate between the two end-members. This is particularly interesting because Asteroid 24 Themis was recently discovered to have H 2O ice on the surface (Rivkin, A., Emery, J. [2010]. Nature 464, 1322-1323; Campins, H. et al. [2010a]. Nature 464, 1320-1321).
Published: 2011
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24. Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission

Author: Athena Coustenis, Georgios Bampasidis, Conor A. Nixon, Laurette Piani, F. M. Flasar, Sandrine Vinatier, Nicholas A Teanby, Paul N. Romani, Richard K. Achterberg, Gordon L. Bjoraker, Ronald Carlson, D. E. Jennings, Panayotis Lavvas, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), NASA/Goddard Space Flight Center (NASA/GSFC), Department of Astronomy, University of Maryland, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Atmospheric, Oceanic and Planetary Physics, Department of Physics, Clarendon Laboratory, University of Oxford, IACS, Catholic University of America, Muséum national d'Histoire naturelle (MNHN), and National and Kapodistrian University of Athens (NKUA)
Subjects: ICARUS, Solar System, symbols.namesake, Space and Planetary Science, General Circulation Model, symbols, Environmental science, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Spectral line, Latitude, Astrobiology
Abstract: This paper reports on the results from an extensive study of all nadir-looking spectra acquired by Cassini/CIRS during the 44 flybys performed in the course of the nominal mission (2004-2008). With respect to the previous study (Coustenis, A., and 24 colleagues [2007]. Icarus 189, 35-62, on flybys TB-T10) we present here a significantly richer dataset with, in particular, more data at high northern and southern latitudes so that the abundances inferred here at these regions are more reliable. Our enhanced high-resolution dataset allows us to infer more precisely the chemical composition of Titan all over the disk. We also include improved spectroscopic data for some molecules and updated temperature profiles. The latitudinal distributions of all of the gaseous species are inferred. We furthermore test vertical distributions essentially for acetylene (C 2H 2) from CIRS limb-inferred data and from current General Circulation Models for Titan and compare our results on all the gaseous abundances with predictions from 1-D photochemical-radiative models to check the reliability of the chemical reactions and pathways. © 2009 Elsevier Inc.
Published: 2010
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25. Martian atmosphere as observed by VIRTIS-M on Rosetta spacecraft

Author: Sergio Fonti, Angioletta Coradini, Yves Langevin, G. P. Tozzi, Gianrico Filacchione, Michael R. Combi, Dominique Bockelée-Morvan, Didier Tiphene, Stefano Mottola, Bernard Schmitt, J. Crovisier, M. A. Barucci, Gianfranco Magni, Giovanna Rinaldi, Armando Blanco, Eleonora Ammannito, Vincenzo Orofino, Costanzo Federico, Pierre Drossart, Pasquale Palumbo, Ralf Jaumann, Luigi Colangeli, Wing-Huen Ip, Giancarlo Bellucci, Priscilla Cerroni, M. T. Capria, Vittorio Formisano, Giuseppe Piccioni, J. P. Bibring, Fredric W. Taylor, T. Encrenaz, Pgj Irwin, Uwe Fink, Gabriele Arnold, Paulina Wolkenberg, R. W. Carlson, G. Neukum, Davide Grassi, Johannes Benkhoff, M. Combes, Fabrizio Capaccioni, Stéphane Erard, Heike Rauer, T. B. McCord, Vito Mennella, Federico Tosi, E. Kuehrt, M. C. De Sanctis, Uri Carsenty, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Dipartimento di Fisica, Università di Lecce, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Atmospheric, Oceanic, and Space Science Department, University of Michigan (AOSS), Università degli Studi di Perugia = University of Perugia (UNIPG), Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona (LPL), Graduate Institute of Astronomy, Atmospheric, Oceanic and Planetary Physics, Department of Physics, Clarendon Laboratory, University of Oxford, Bear Fight Center, Space Science Institute, Winthrop, Dipartimento di Scienze Applicate, Università Parthenope di Napoli, Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA)
Subjects: MESH: Rosetta mission, Atmospheric Science, Daytime, Opacity, martian atmosphere, virtis, rosetta, Solar zenith angle, Soil Science, Aquatic Science, Oceanography, Atmospheric sciences, Planetary Sciences: Solid Surface Planets: Instruments and techniques, Atmosphere, Geochemistry and Petrology, MESH: CO2, Earth and Planetary Sciences (miscellaneous), Planetary Sciences: Solid Surface Planets: Atmospheres (0343, Radiometric calibration, Earth-Surface Processes, Water Science and Technology, Ecology, Spectrometer, Paleontology, Forestry, Mars Exploration Program, Atmosphere of Mars, Planetary Sciences: Solid Surface Planets: Remote sensing, 1060), Geophysics, Space and Planetary Science, MESH: temperature profile, Environmental science, MESH: Mars atmosphere, MESH: 67P/Churyumov‐Gerasimenko, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The Rosetta spacecraft accomplished a flyby of Mars on its way to 67P/Churyumov-Gerasimenko on 25 February 2007. In this paper we describe the measurements obtained by the M channel of the Visual and Infrared Thermal Imaging Spectrometer (VIRTIS-M) and the first scientific results derived from their analysis. The broad spectral coverage of the VIRTIS-M in the IR permitted the study of various phenomena occurring in the Martian atmosphere; observations were further exploited to achieve accurate absolute radiometric calibration. Nighttime data from the VIRTIS-M constrain the air temperature profile in the lower atmosphere (5-30 km), using variations in CO2 opacity at 4.3 mum. A comparison of this data with the global circulation model (GCM) by Forget et al. (1999) shows a trend of slightly higher air temperature in the VIRTIS-M retrievals; this is accompanied by the presence of moderate decreases (˜5 K) in large sections of the equatorial region. This is potentially related to the occurrence of water ice clouds. Daytime data from the VIRTIS-M reveal CO2 non-local thermodynamic equilibrium emission in the high atmosphere. A mapping of emission intensity confirms its strict dependence on solar zenith angle. Additionally, devoted limb observations allowed the retrieval of vertical emission intensity profiles, indicating a peak around 105 km in southern tropical regions. Ozone content can be effectively monitored by the emission of O2 (a1Deltag) at 1.27 mum. Retrieved emission intensity shows that polar regions are particularly rich in ozone. Aerosol scattering was observed in the 1-2.5 mum region above the night region above the night disk, suggesting the occurrence of very high noctilucent clouds.
Published: 2010
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26. 3D simulations of supernova remnants evolution including non-linear particle acceleration

Author: Jean Ballet, Romain Teyssier, Gilles Ferrand, Federico Fraschetti, Anne Decourchelle, University of Zurich, Ferrand, G, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institute für Theoretische Physik, Universität Zürich, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institute for Theoretical Physics, Universität Zürich [Zürich] = University of Zurich (UZH), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Lunar and Planetary Laboratory [Tucson] (LPL), ANR-07-JCJC-0008,ACCELRSN,Accélération de protons dans les Restes de Supernova(2007), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Zürich [Zürich] (UZH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and ANR-07-JCJC-0008,JCJC,Accélération de protons dans les Restes de Supernova(2007)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], 530 Physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Astrophysics, 01 natural sciences, Instability, Acceleration, cosmic rays, 1912 Space and Planetary Science, 0103 physical sciences, Adiabatic process, Supernova remnant, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, acceleration of particles, Physics, supernova remnants, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astronomy and Astrophysics, Shock (mechanics), Particle acceleration, Supernova, Space and Planetary Science, instabilities, 10231 Institute for Computational Science, 3103 Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena
Abstract: If a sizeable fraction of the energy of supernova remnant shocks is channeled into energetic particles (commonly identified with Galactic cosmic rays), then the morphological evolution of the remnants must be distinctly modified. Evidence of such modifications has been recently obtained with the Chandra and XMM-Newton X-ray satellites. To investigate these effects, we coupled a semi-analytical kinetic model of shock acceleration with a 3D hydrodynamic code (by means of an effective adiabatic index). This enables us to study the time-dependent compression of the region between the forward and reverse shocks due to the back reaction of accelerated particles, concomitantly with the development of the Rayleigh-Taylor hydrodynamic instability at the contact discontinuity. Density profiles depend critically on the injection level eta of particles: for eta up to about 10^-4 modifications are weak and progressive, for eta of the order of 10^-3 modifications are strong and immediate. Nevertheless, the extension of the Rayleigh-Taylor unstable region does not depend on the injection rate. A first comparison of our simulations with observations of Tycho's remnant strengthens the case for efficient acceleration of protons at the forward shock., accepted for publication in A&A (final version)
Published: 2009
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27. VIMS spectral mapping observations of Titan during the Cassini prime mission

Author: Laurence A. Soderblom, Angioletta Coradini, Priscilla Cerroni, Dale P. Cruikshank, Ralf Jaumann, Caitlin A. Griffith, Katrin Stephan, Vittorio Formisano, Dennis L. Matson, Thomas B. McCord, Jason M. Soderblom, Roger N. Clark, Pierre Drossart, K. M. Pitman, P. D. Nicholson, Bruno Sicardy, Paulo Penteado, Paul O. Hayne, Bonnie J. Buratti, G. Vixie, Yves Langevin, Jean-Pierre Bibring, Christophe Sotin, Stéphane Le Mouélic, Robert H. Brown, Kevin H. Baines, Jason W. Barnes, Sebastien Rodriguez, Robert M. Nelson, Fabrizio Capaccioni, Giancarlo Bellucci, Federico Tosi, University of Idaho [Moscow, USA], Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), United States Geological Survey, Denver, DLR Institut für Planetenerkundung, Bear Fight Center, Space Science Institute, Winthrop, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), United States Geological Survey, Astrogeology Division, Earth and Space Sciences Department, University of California, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), SETI Institute, NASA Ames Research Center, Moffett Field, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Astronomy, Cornell University, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Planetary Science Institute [Tucson] (PSI), Institute of Geological Sciences [Berlin], Department of Earth Sciences [Berlin], Free University of Berlin (FU)-Free University of Berlin (FU), Bear Fight Institute, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), NASA Ames Research Center (ARC), Cornell University [New York], Pôle Astronomie du LESIA, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
Subjects: [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Astrobiology, symbols.namesake, Spectral mapping, Space and Planetary Science, symbols, VIMS, Cassini, Titan (rocket family), Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Remote sensing
Abstract: International audience; This is a data paper designed to facilitate the use of and comparisons to Cassini/visual and infrared mapping spectrometer (VIMS) spectral mapping data of Saturn's moon Titan. We present thumbnail orthographic projections of flyby mosaics from each Titan encounter during the Cassini prime mission, 2004 July 1 through 2008 June 30. For each flyby we also describe the encounter geometry, and we discuss the studies that have previously been published using the VIMS dataset. The resulting compliation of metadata provides a complementary big-picture overview of the VIMS data in the public archive, and should be a useful reference for future Titan studies.
Published: 2009
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28. Saturn's Titan: Surface change, ammonia, and implications for atmospheric and tectonic activity

Author: Patrick G. J. Irwin, Thomas B. McCord, Fabrizio Capaccioni, Gianrico Filacchione, Vito Mennella, Bruno Sicardy, Roger N. Clark, Bruce Hapke, Dennis L. Matson, P. D. Nicholson, Christophe Sotin, Priscilla Cerroni, Jean-Pierre Bibring, Vittorio Formisano, Giancarlo Bellucci, Kevin H. Baines, F. Leader, Angioletta Coradini, William D. Smythe, John C. Pearl, M. D. Boryta, Ralf Jaumann, Pierre Drossart, Dale P. Cruikshank, L. W. Kamp, M. Combes, R.Y. Langevin, Jonathan I. Lunine, Robert M. Nelson, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Earth and Space Science Division, JPL/NASA, Atmospheric, Oceanic and Planetary Physics, Department of Physics, Clarendon Laboratory, University of Oxford, Department of Geology, Mount San Antonio College, Walnut, Department of Planetary Exploration, DLR, US Geological Survey, Denver, National Aeronautics and Space Administration, Ames Research Center, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Goddard Space Flight Center, NASA, Astrophysics Science Division, University of Pittsburgh, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), University of Washington, Winthrop, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University
Subjects: 010504 meteorology & atmospheric sciences, Ices, chemistry.chemical_element, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Atmospheric sciences, 01 natural sciences, Astrobiology, Latitude, Ammonia, chemistry.chemical_compound, symbols.namesake, 0103 physical sciences, Surface change, 010303 astronomy & astrophysics, Spectroscopy, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Infrared observations, Astronomy and Astrophysics, Reflectivity, Nitrogen, Tectonics, chemistry, 13. Climate action, Space and Planetary Science, Spectrophotometry, symbols, Environmental science, Titan (rocket family), Longitude, Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Titan is known to have a young surface. Here we present evidence from the Cassini Visual and Infrared Mapping Spectrometer that it is currently geologically active. We report that changes in the near-infrared reflectance of a 73,000 km 2 area on Titan (latitude 26° S, longitude 78° W) occurred between July 2004 and March of 2006. The reflectance of the area increased by a factor of two between July 2004 and March-April 2005; it then returned to the July 2004 level by November 2005. By late December 2005 the reflectance had surged upward again, establishing a new maximum. Thereafter, it trended downward for the next three months. Detailed spectrophotometric analyses suggest these changes happen at or very near the surface. The spectral differences between the region and its surroundings rule out changes in the distribution of the ices of reasonably expected materials such as H 2O, CO 2, and CH 4 as possible causes. Remarkably, the change is spectrally consistent with the deposition and removal of NH 3 frost over a water ice substrate. NH 3 has been proposed as a constituent of Titan's interior and has never been reported on the surface. The detection of NH 3 frost on the surface might possibly be explained by episodic effusive events occur which bring juvenile ammonia from the interior to the surface. If so, its decomposition would feed nitrogen to the atmosphere now and in the future. The lateral extent of the region exceeds that of active areas on the Earth (Hawaii) or Io (Loki).
Published: 2009
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29. Earth-Based Support for the Titan Saturn System Mission

Author: Ralph D. Lorenz, Athena Coustenis, Leonid I. Gurvits, Hunter Waite, Mathieu Hirtzig, Jonathan I. Lunine, Dennis L. Matson, Kim Reh, Jean-Pierre Lebreton, Christian Erd, Patricia Beauchamp, Christophe Sotin, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, ESA-ESTEC, Jet Propulsion Laboratory, California Institute of Technology (JPL), Applied Physics Laboratory, Johns Hopkins University, Southwest Research Institute, and Joint Institute for VLBI in Europe (JIVE)
Subjects: Exploration of Saturn, Aerobot, Outer planets, Astronomy and Astrophysics, law.invention, Astrobiology, Orbiter, symbols.namesake, Planetary science, Space and Planetary Science, law, Earth and Planetary Sciences (miscellaneous), symbols, Environmental science, Space Science, Titan (rocket family), Enceladus, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The Titan Saturn System Mission (TSSM) concept is composed of a TSSM orbiter provided by NASA that would carry two Titan in situ elements provided by ESA: the montgolfière and the probe/lake lander. One overarching goal of TSSM is to explore in situ the atmosphere and surface of Titan. The mission has been prioritized as the second Outer Planets Flagship Mission, the first one being the Europa Jupiter System Mission (EJSM). TSSM would launch around 2023-2025 arriving at Saturn 9 years later followed by a 4-year science mission in the Saturn system. Following delivery of the in situ elements to Titan, the TSSM orbiter would explore the Saturn system via a 2-year tour that includes Enceladus and Titan flybys before entering into a dedicated orbit around Titan. The Titan montgolfière aerial vehicle under consideration will circumnavigate Titan at a latitude of ~20° and at altitudes of ~10 km for a minimum of 6 months. The probe/lake lander will descend through Titan's atmosphere and land on the liquid surface of Kraken Mare (~75° north latitude). As for any planetary space science mission, and based on the Cassini-Huygens experience, Earth-based observations will be synergistic and enable scientific optimization of the return of such a mission. Some specific examples of how this can be achieved (through VLBI and Doppler tracking, continuous monitoring of atmospheric and surface features, and Direct-to-Earth transmission) are described in this paper.
Published: 2009
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30. Comparing methane and temperature profiles on Titan in 1980 and 2005

Author: M. Fulchignoni, Caitlin A. Griffith, Francesca Ferri, C. P. McKay, Space Science Division, NASA Ames Research, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Haze, Humidity, Astronomy and Astrophysics, Atmospheric sciences, Methane, chemistry.chemical_compound, symbols.namesake, chemistry, Space and Planetary Science, symbols, Environmental science, Relative humidity, Tropopause, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stratosphere
Abstract: International audience; The Huygens Probe data provided a direct measurement of CH 4, temperature, and pressure in Titan's atmosphere. This data can be used to compare to the Voyager data in which the effects of CH 4, temperature, and pressure were mixed together. Comparison with Huygens data indicates that values of the surface relative humidity of CH 4 at the Voyager ingress and egress were between 20% and 45%, and values above 60% are inconsistent with this comparison. The most parsimonious explanation for the Voyager data is that the temperature and CH 4 surface humidity at the Voyager ingress and egress profiles were identical to the Huygens values; a surface temperature of 93.65±0.25 K, and a surface relative humidity of 43%. Thus, it is likely that these values have characterized the equatorial region of Titan from 1980 until 2005. The small reduction of 1 K, between the tropopause temperatures of the Voyager profiles and the tropopause temperature of the Huygens profile is explainable by a change in the antigreenhouse flux from the stratosphere from 0.13 to 0.1 of the total average solar flux. This could result from a small seasonal change in the optical properties of the stratospheric haze.
Published: 2009
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31. Datura family: the 2009 update

Author: I. Slyusarev, Yu. N. Krugly, Tadeusz Michalowski, E. C. Beshore, François Colas, N. M. Gaftonyuk, Agnieszka Kryszczyńska, David Nesvorný, Magdalena Polińska, Jean Lecacheux, David Vokrouhlický, Igor Molotov, Josef Ďurech, Institute of Astronomy, Faculty of Mathematics and Physics, Charles University, Adam Mickiewicz University in Poznań (UAM), Institute of Astronomy, Kharkiv National University, Crimean Astrophysical Observatory (CrAO), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Keldysh Institute of Applied Mathematics, Russian Academy of Science, Southwest Research Institute, Lunar and Planetary Laboratory [University of Arizona] (LPL), and University of Arizona
Subjects: Physics, Rotation period, Synodic day, Astronomy, Astronomy and Astrophysics, Astrophysics, Moment of inertia, Light curve, Space and Planetary Science, Asteroid, Planet, [SDU]Sciences of the Universe [physics], Asteroid belt, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Galaxy rotation curve
Abstract: International audience; Context: Research of asteroid families has been recently refreshed by the discovery of very young ones. These families are of great interest because they represent the product of their parent body fragmentation before orbital and physical evolutionary processes can change them. A cluster of seven objects around the largest body (1270) Datura is of particular interest because it has enough known members and resides in the inner part of the main asteroid belt, facilitating observations. Aims: We carried out photometric observations of the two largest members of the Datura family - asteroids (1270) Datura and (90265) 2003 CL5 - with the goal of inferring their physical parameters. We also used numerous astrometric observations of Datura-family members in the past few years to revisit the age of this cluster. Methods: We performed numerous photometric observations of (1270) Datura over several oppositions. We then used the lightcurve inversion method to determine the spin state and shape of this asteroid. In the case of (90265) 2003 CL5, for which only limited lightcurve data have been acquired so far, we used Fourier analysis to determine the synodic rotation period during the 2008 apparition. We also used backward numerical integration of the improved orbits of Datura family members to reduce uncertainty in its age. Results: We determined the rotation state of (1270) Datura, the largest member of its own family. Its major properties are a short rotation period of ~3.36 h and small obliquity, which, however, exhibits ~±15° excursions because of a forced Cassini state of the proper nodal frequency. Any possible initial non-principal rotation state has probably been damped and the asteroid rotates about the shortest axis of the inertia tensor. Its global shape, although convex in our representation, may reflect regions related to the excavation of the family members from the parent body surface. Interestingly, the second largest member of the Datura family - (90265) 2003 CL5 - appears to be very slow rotator with the rotation period ~24 h. The large amplitude of its rotation curve suggests that its shape is extremely elongated, possibly bi-lobed. Improved orbits of the family members allow us to re-determine the possible age of this family. We find an age that is slightly older than previously reported. Using a conservative approach, we obtain an age in the 450 to 600 kyr range. With strengthened, but plausible, conditions, we find that the current data may support an age of 530±20 kyr. Further astrometric and photometric observations of the Datura cluster members are needed to determine its age more accurately.
Published: 2009
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32. Methane in Titan's atmosphere: from fundamental spectroscopy to planetology

Author: Vincent Boudon, Caitlin A. Griffith, Emmanuel Lellouch, Alberto Negrão, Pierre Drossart, Mathieu Hirtzig, Tony Gabard, Bruno Bézard, Catherine De Bergh, Michel Loete, Jean Paul Champion, Athena Coustenis, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Technologie de Belfort-Montbeliard (UTBM)-Université de Bourgogne (UB)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Istituto di Fisica dello Spazio Interplanetario (IFSI-Roma), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, and Champion, Jean Paul
Subjects: Origin of water on Earth, General Physics and Astronomy, Methane, [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Astrobiology, chemistry.chemical_compound, symbols.namesake, Natural gas, Planetologie, Physics::Chemical Physics, Atmosphere of Titan, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, Spectroscopy, Life on Titan, business.industry, Planetary science, chemistry, Greenhouse gas, Physics::Space Physics, symbols, Environmental science, Astrophysics::Earth and Planetary Astrophysics, business, Titan (rocket family), Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The methane molecule (CH4) is relatively abundant in the Universe and in particular in our Solar System. On Earth, it is the main compound of natural gas and is also the second greenhouse gas of anthropic origin. On Saturn's satellite Titan it plays a role similar to water on Earth and leads to a complex chemistry.
Published: 2009
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33. Theoretical Modeling for the STEREO Mission

Author: Thomas H. Zurbuchen, Karoly Kecskemety, M. J. Reiner, Charlie J. Farrugia, Jon A. Linker, Antoinette B. Galvin, A. Llebaria, Noé Lugaz, J. W. Cook, Dusan Odstrcil, Sami K. Solanki, Rainer Schwenn, David M. Alexander, Martin A. Lee, Manfred Scholer, Victor J. Pizzo, József Kóta, Markus J. Aschwanden, Ilia I. Roussev, Vytenis M. Vasyliunas, L. F. Burlaga, Robert F. Wimmer-Schweingruber, Bernd Inhester, Anne Sandman, Ward B. Manchester, Thomas Wiegelmann, Donald V. Reames, Peter Bochsler, Peter A. Robinson, Pete Riley, Milan Maksimovic, M. L. Kaiser, C. K. Ng, Janet G. Luhmann, Z. Mikic, Volker Bothmer, Russell A. Howard, Tamas I. Gombosi, L. M. Blush, P. C. Liewer, Iver H. Cairns, Lockheed Martin Solar and Astrophysics Laboratory, NASA/Goddard Space Flight Center (NASA/GSFC), Astronomy Department, University of Michigan, University of New Hampshire (UNH), SAIC, Department of Physics and Astronomy, Rice University, Houston, Naval Research Laboratory (NRL), NOAA/SEC, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), University of California, Space Sciences Lab, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Physikalisches Institut, Universität Bern, School of Physics, University of Sydney, Institut für Astrophysik, Universität Göttingen, KFKI Research Institute for Particle and Nuclear Physics (KFKI-RMKI), Laboratoire d'Astronomie Spatiale (LAS), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique des plasmas, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Center for Interdisciplinary Plasma Science, and Extraterr
Subjects: Physics, 010504 meteorology & atmospheric sciences, Solar energetic particles, Solar flare, business.industry, Astronomy, Astronomy and Astrophysics, Magnetic reconnection, Space weather, 01 natural sciences, Corona, STEREO mission, Solar corona, Solar wind, Coronal mass ejection (CME), Solar filaments . Heliosphere, Interplanetary shocks, Interplanetary particle beams, Solar energetic particle events (SEP), Solar flares, Stereoscopy, 3D reconstruction techniques, White-light emission, EUV emission, Interplanetary radio emission, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Aerospace engineering, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Heliosphere, 0105 earth and related environmental sciences
Abstract: International audience; We summarize the theory and modeling efforts for the STEREO mission, which will be used to interpret the data of both the remote-sensing (SECCHI, SWAVES) and in-situ instruments (IMPACT, PLASTIC). The modeling includes the coronal plasma, in both open and closed magnetic structures, and the solar wind and its expansion outwards from the Sun, which defines the heliosphere. Particular emphasis is given to modeling of dynamic phenomena associated with the initiation and propagation of coronal mass ejections (CMEs). The modeling of the CME initiation includes magnetic shearing, kink instability, filament eruption, and magnetic reconnection in the flaring lower corona. The modeling of CME propagation entails interplanetary shocks, interplanetary particle beams, solar energetic particles (SEPs), geoeffective connections, and space weather. This review describes mostly existing models of groups that have committed their work to the STEREO mission, but is by no means exhaustive or comprehensive regarding alternative theoretical approaches.
Published: 2008
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34. A close look at Saturn's rings with Cassini VIMS

Author: Priscilla Cerroni, Matthew M. Hedman, Dale P. Cruikshank, Robert H. Brown, Philip D. Nicholson, Jeffrey N. Cuzzi, Roger N. Clark, Mark R. Showalter, Gianrico Filacchione, Pierre Drossart, Bruno Sicardy, Kevin H. Baines, Angioletta Coradini, Bonnie J. Buratti, Fabrizio Capaccioni, Gary B. Hansen, Department of Astronomy, Cornell University, US Geological Survey, Denver, Search for Extraterrestrial Intelligence Institute (SETI), SETI Institute, NASA Ames Research Center, Moffett Field, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Department of Earth and Space Sciences, University of Washington, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), and Istituto de Astrofisica de Fisica dello Spazio Interplanetario
Subjects: Physics, Opacity, business.industry, Rings of Saturn, Astronomy and Astrophysics, Astrophysics, Radius, Ring (chemistry), Spectral line, Wavelength, Optics, Space and Planetary Science, Saturn, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Optical depth
Abstract: International audience; Soon after the Cassini-Huygens spacecraft entered orbit about Saturn on 1 July 2004, its Visual and Infrared Mapping Spectrometer obtained two continuous spectral scans across the rings, covering the wavelength range 0.35-5.1 mum, at a spatial resolution of 15-25 km. The first scan covers the outer C and inner B rings, while the second covers the Cassini Division and the entire A ring. Comparisons of the VIMS radial reflectance profile at 1.08 mum with similar profiles at a wavelength of 0.45 mum assembled from Voyager images show very little change in ring structure over the intervening 24 years, with the exception of a few features already known to be noncircular. A model for single-scattering by a classical, many-particle-thick slab of material with normal optical depths derived from the Voyager photopolarimeter stellar occultation is found to provide an excellent fit to the observed VIMS reflectance profiles for the C ring and Cassini Division, and an acceptable fit for the inner B ring. The A ring deviates significantly from such a model, consistent with previous suggestions that this region may be closer to a monolayer. An additional complication here is the azimuthally-variable average optical depth associated with "self-gravity wakes" in this region and the fact that much of the A ring may be a mixture of almost opaque wakes and relatively transparent interwake zones. Consistently with previous studies, we find that the near-infrared spectra of all main ring regions are dominated by water ice, with a typical regolith grain radius of 5-20 mum, while the steep decrease in visual reflectance shortward of 0.6 mum is suggestive of an organic contaminant, perhaps tholin-like. Although no materials other than H 2O ice have been identified with any certainty in the VIMS spectra of the rings, significant radial variations are seen in the strength of the water-ice absorption bands. Across the boundary between the C and B rings, over a radial range of ˜7000 km, the near-IR band depths strengthen considerably. A very similar pattern is seen across the outer half of the Cassini Division and into the inner A ring, accompanied by a steepening of the red slope in the visible spectrum shortward of 0.55 mum. We attribute these trends---as well as smaller-scale variations associated with strong density waves in the A ring---to differing grain sizes in the tholin-contaminated icy regolith that covers the surfaces of the decimeter-to-meter sized ring particles. On the largest scale, the spectral variations seen by VIMS suggest that the rings may be divided into two larger 'ring complexes,' with similar internal variations in structure, optical depth, particle size, regolith texture and composition. The inner complex comprises the C and B rings, while the outer comprises the Cassini Division and A ring.
Published: 2008
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35. Heat balance in Titan's atmosphere

Author: Lyn R. Doose, Martin G. Tomasko, Bruno Bézard, S. Engel, Sandrine Vinatier, Erich Karkoschka, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Haze, Radiative cooling, Meteorology, business.industry, Solar zenith angle, Astronomy and Astrophysics, Solar energy, Atmospheric sciences, Aerosol, Latitude, symbols.namesake, Heat flux, Space and Planetary Science, Physics::Space Physics, symbols, Astrophysics::Solar and Stellar Astrophysics, Environmental science, Astrophysics::Earth and Planetary Astrophysics, business, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Physics::Atmospheric and Oceanic Physics
Abstract: International audience; The recent measurements of the vertical distribution and optical properties of haze aerosols as well as of the absorption coefficients for methane at long paths and cold temperatures by the Huygens entry probe of Titan permit the computation of the solar heating rate on Titan with greater certainty than heretofore. We use the haze model derived from the Descent Imager/Spectral Radiometer (DISR) instrument on the Huygens probe [Tomasko, M.G., Doose, L., Engel, S., Dafoe, L.E., West, R., Lemmon, M., Karkoschka, E., See, C., 2008a. A model of Titan's aerosols based on measurements made inside the atmosphere. Planet. Space Sci., this issue, doi:10.1016/j.pss.2007.11.019] to evaluate the variation in solar heating rate with altitude and solar zenith angle in Titan's atmosphere. We find the disk-averaged solar energy deposition profile to be in remarkably good agreement with earlier estimates using very different aerosol distributions and optical properties. We also evaluated the radiative cooling rate using measurements of the thermal emission spectrum by the Cassini Composite Infrared Spectrometer (CIRS) around the latitude of the Huygens site. The thermal flux was calculated as a function of altitude using temperature, gas, and haze profiles derived from Huygens and Cassini/CIRS data. We find that the cooling rate profile is in good agreement with the solar heating profile averaged over the planet if the haze structure is assumed the same at all latitudes. We also computed the solar energy deposition profile at the 10°S latitude of the probe-landing site averaged over one Titan day. We find that some 80% of the sunlight that strikes the top of the atmosphere at this latitude is absorbed in all, with 60% of the incident solar energy absorbed below 150 km, 40% below 80 km, and 11% at the surface at the time of the Huygens landing near the beginning of summer in the southern hemisphere. We compare the radiative cooling rate with the solar heating rate near the Huygens landing site averaging over all longitudes. At this location, we find that the solar heating rate exceeds the radiative cooling rate by a maximum of 0.5 K/Titan day near 120 km altitude and decreases strongly above and below this altitude. Since there is no evidence that the temperature structure at this latitude is changing, the general circulation must redistribute this heat to higher latitudes.
Published: 2008
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36. Surface composition of Hyperion

Author: Jean-Pierre Bibring, R. N. Clark, Angioletta Coradini, Yves Langevin, Dale P. Cruikshank, P. D. Nicholson, B. J. Buratti, Robert H. Brown, Bruno Sicardy, T. B. McCord, Katrin Stephan, Priscilla Cerroni, Vittorio Formisano, Gianrico Filacchione, Giancarlo Bellucci, Amanda R. Hendrix, Kevin H. Baines, Dennis L. Matson, Allan W. Meyer, Robert M. Nelson, Pierre Drossart, J. B. Dalton, M. Combes, James M. Bauer, Christophe Sotin, Candice Hansen, C. M. Dalle Ore, Fabrizio Capaccioni, Vito Mennella, Federico Tosi, Ralf Jaumann, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), SETI Institute, NASA Ames Research Center, Moffett Field, Search for Extraterrestrial Intelligence Institute (SETI), Jet Propulsion Laboratory, California Institute of Technology (JPL), Department of Planetary Exploration, DLR, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), US Geological Survey, Denver, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Space Science Institute, Winthrop, Department of Astronomy, Cornell University, Université de Nantes (UN), Universities Space Research Association - Stratospheric Observatory for Infrared Astronomy (USRA -SOFIA), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC)
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, Rotation, 01 natural sciences, Spectral line, Icy Satellites, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Impact crater, Saturn, 0103 physical sciences, VIMS, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing, Multidisciplinary, Spacecraft, business.industry, Albedo, 13. Climate action, Cassini, Satellite, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Hyperion, Geology
Abstract: International audience; Hyperion, Saturn's eighth largest icy satellite, is a body of irregular shape in a state of chaotic rotation. The surface is segregated into two distinct units. A spatially dominant high-albedo unit having the strong signature of H2O ice contrasts with a unit that is about a factor of four lower in albedo and is found mostly in the bottoms of cup-like craters. Here we report observations of Hyperion's surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft at closest approach during a fly-by on 25-26 September 2005. The close fly-by afforded us the opportunity to obtain separate reflectance spectra of the high- and low-albedo surface components. The low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe and a hemisphere-wide superficial coating on Iapetus.
Published: 2007
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37. Saturn's icy satellites investigated by Cassini-VIMS. I. Full-disk properties: 350 5100 nm reflectance spectra and phase curves

Author: Filacchione, Gianrico, Capaccioni, Fabrizio, Mccord, Thomas B., Coradini, Angioletta, Cerroni, Priscilla, Bellucci, Giancarlo, Tosi, Federico, d'Aversa, E., Formisano, Vittorio, Brown, Robert H., Baines, Kevin H., Bibring, Jean-Pierre, Buratti, B. J., Clark, Roger N., Combes, Michel, Cruikshank, Dale P., Drossart, Pierre, Jaumann, Ralf, Langevin, Yves, Matson, Dennis L., Mennella, Vito, Nelson, Robert M., Nicholson, Philip D., Sicardy, Bruno, Sotin, Christophe, Hansen, Gary B., Hibbitts, K., Showalter, Mark R., Newman, S., Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Bear Fight Center, Space Science Institute, Winthrop, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona (LPL), Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), United States Geological Survey, Denver, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), NASA Ames Research Center, Astrophysics Branch, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Department of Astronomy, Cornell University, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Space Sciences, University of Washington, and Department of Electrical Engineering, Stanford University
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Saturn's icy satellites are among the main scientific objectives of the Cassini-VIMS (Visual and Infrared Mapping Spectrometer) experiment. This paper contains a first systematic and comparative analysis of the full-disk spectral properties of Dione, Enceladus, Epimetheus, Hyperion, Iapetus, Mimas, Phoebe, Rhea and Tethys as observed by VIMS from July 2004 to June 2005. The disk integrated properties (350-5100 nm reflectance spectra and phase curves at 550-2232 nm) and images of satellites are reported and discussed in detail together with the observed geometry. In general, the spectra in the visible spectral range are almost featureless and can be classified according to the spectral slopes: from the bluish Enceladus and Phoebe to the redder Iapetus, Hyperion and Epimetheus. In the 1000-1300 nm range the spectra of Enceladus, Tethys, Mimas and Rhea are characterized by a negative slope, consistent with a surface largely dominated by water ice, while the spectra of Iapetus, Hyperion and Phoebe show a considerable reddening pointing out the relevant role played by darkening materials present on the surface. In between these two classes are Dione and Epimetheus, which have a flat spectrum in this range. The main absorption bands identified in the infrared are the 1520, 2020, 3000 nm H 2O/OH bands (for all satellites), although Iapetus dark terrains show mostly a deep 3000 nm band while the 1520 and 2020 nm bands are very faint. In this spectral range, the Iapetus spectrum is characterized by a strong reddening. The CO 2 band at 4260 nm and the Fresnel ice peak around 3100 nm are evident only on Hyperion, Phoebe and Iapetus. The phase curves at 550 and at 2232 nm are reported for all the available observations in the 0°-144° range; Rhea shows an opposition surge at visible wavelengths in the 0.5°-1.17° interval. The improvement on the retrieval of the full-disk reflectance spectra can be appreciated by a direct comparison with ground-based telescopic data available from literature. Finally, data processing strategies and recent upgrades introduced in the VIMS-V calibration pipeline (flat-field and destriping-despiking algorithm) are discussed in appendices.
Published: 2007
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38. Composition and Physical Properties of Enceladus' Surface

Author: Christophe Sotin, Priscilla Cerroni, Dennis L. Matson, Jason W. Barnes, P. D. Nicholson, Dale P. Cruikshank, Ralf Jaumann, Bruno Sicardy, Giancarlo Bellucci, Robert M. Nelson, Bonnie J. Buratti, Thomas B. McCord, S. Newman, R. N. Clark, James M. Bauer, Yves Langevin, M. Combes, Vittorio Formisano, Pierre Drossart, Robert H. Brown, Rachel Mastrapa, Kevin H. Baines, Tom Momary, Fabrizio Capaccioni, Angioletta Coradini, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, US Geological Survey, Flagstaff, Jet Propulsion Laboratory, California Institute of Technology (JPL), SETI Institute, NASA Ames Research Center, Moffett Field, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Instituto di Astrofisica Spaziale - CNR, Area della recerca di Tor Vergata, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Earth and Space Sciences, University of Washington, Department of Astronomy, Cornell University, and Université de Nantes (UN)
Subjects: Surface (mathematics), Materials science, Extraterrestrial Environment, Spectrophotometry, Infrared, 010504 meteorology & atmospheric sciences, Infrared, Saturnian satellites, 01 natural sciences, Astrobiology, Enceladus, Ammonia, 0103 physical sciences, VIMS, Ice Cover, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Multidisciplinary, Spectrometer, Atmosphere, Ice, surface composition, Carbon Dioxide, Amorphous solid, Satellites de Glace, Saturn, 13. Climate action, Cassini, Satellite, Water ice, Atmospheric column, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO 2 , and amorphous and crystalline water ice, particularly in the region dubbed the âtiger stripes.â An upper limit of 5 precipitable nanometers is derived for CO in the atmospheric column above Enceladus, and 2% for NH 3 in global surface deposits. Upper limits of 140 kelvin (for a filled pixel) are derived for the temperatures in the tiger stripes.
Published: 2006
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39. Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys

Author: Roger N. Clark, Ralf Jaumann, T. Momary, Robert H. Brown, Kevin H. Baines, T. B. McCord, Christophe Sotin, D. P. Simonelli, Joel A. Mosher, Bonnie J. Buratti, Bruno Sicardy, P. D. Nicholson, Michael D. Hicks, Jet Propulsion Laboratory, California Institute of Technology (JPL), Université de Nantes (UN), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, US Geological Survey, Denver, Space Science Institute, Winthrop, Department of Planetary Exploration, DLR, Department of Astronomy, Cornell University, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Haze, 010504 meteorology & atmospheric sciences, Opacity, Astronomy and Astrophysics, Surface finish, Geophysics, 01 natural sciences, law.invention, Photometry (optics), Wavelength, symbols.namesake, Orbiter, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, law, 0103 physical sciences, symbols, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract: Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1–5 μm region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and particle characteristics. Images from the early Titan flybys, particularly T0, Ta, and T5 have been analyzed to create albedo maps in the 2.01 and 2.73 μm windows. We find the average normal reflectance at these two wavelengths to be 0.15±0.02 and 0.035±0.003, respectively. Titan's surface is bifurcated into two albedo regimes, particularly at 2.01 μm. Analysis of these two regimes to understand the physical character of the surface was accomplished with a macroscopic roughness model. We find that the two types of surface have substantially different roughness, with the low-albedo surface exhibiting mean slope angles of not, vert, similar18°, and the high-albedo terrain having a much more substantial roughness with a mean slope angle of not, vert, similar34°. A single-scattering phase function approximated by a one-term Henyey–Greenstein equation was also fit to each unit. Titan's surface is back-scattering (gnot, vert, similar0.3–0.4), and does not exhibit substantially different backscattering behavior between the two terrains. Our results suggest that two distinct geophysical domains exist on Titan: a bright region cut by deep drainage channels and a relatively smooth surface. The two terrains are covered by a film or a coating of particles perhaps precipitated from the satellite's haze layer and transported by eolian processes. Our results are preliminary: more accurate values for the surface albedo and physical parameters will be derived as more data is gathered by the Cassini spacecraft and as a more complete radiative transfer model is developed from both Cassini orbiter and Huygens Lander measurements.
Published: 2006
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40. Titan radar mapper observations from Cassini's T3 fly-by

Author: Pierre Encrenaz, Scott Hensley, William L. Johnson, Ellen R. Stofan, Roberto Seu, R. Boehmer, Steven J. Ostro, Randolph L. Kirk, Rosaly M. C. Lopes, K. Kelleher, Flora Paganelli, Matthew A. Allison, S. Vetrella, E. Flamini, Francesco Posa, G. Francescetti, G. Hamilton, Robert West, Laurence A. Soderblom, Charles A. Wood, Philip S. Callahan, Ralph D. Lorenz, Charles Elachi, S. D. Wall, S. Shaffer, Howard A. Zebker, M. A. Janssen, Bryan Stiles, Yonggyu Gim, L. Roth, Y. Anderson, Giovanni Picardi, Duane O. Muhleman, Jonathan I. Lunine, Lauren Wye, C., Elachi, S., Wall, M., Janssen, E., Stofan, R., Lope, R., Kirk, R., Lorenz, J., Lunine, F., Paganelli, L., Soderblom, C., Wood, L., Wye, H., Zebker, Y., Anderson, S., Ostro, M., Allison, R., Boehmer, P., Callahan, P., Encrenaz, E., Flamini, Franceschetti, Giorgio, Y., Gim, G., Hamilton, S., Hensley, W., Johnson, K., Kelleher, D., Muhleman, G., Picardi, F., Posa, L., Roth, R., Seu, S., Shaffer, B., Stile, Vetrella, Sergio, R., West, Jet Propulsion Laboratory, California Institute of Technology (JPL), Proxemy Research, Bowie, US Geological Survey, Flagstaff, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Planetary Science Institute, Tucson, Stanford University, Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Alenia Aerospazio, Facoltá di Ingegneria, Geological and Planetary Sciences, California Institute of Technology, Pasadena, Universitá La Sapienza, and INFM and Dipartimento Interateneo di Fisica
Subjects: Synthetic aperture radar, geography, Multidisciplinary, geography.geographical_feature_category, Landform, Fluvial, Titan moon, Space-based radar, law.invention, Astrobiology, symbols.namesake, Impact crater, law, symbols, Radiometry, Cassini, Radar Mapper, Radar, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Remote sensing
Abstract: International audience; Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.
Published: 2006
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41. The evolution of Titan's mid-latitude clouds

Author: Vito Mennella, B. J. Buratti, Jason W. Barnes, Yves Langevin, Roger N. Clark, Paulo Penteado, Dale P. Cruikshank, Ralf Jaumann, Robert M. Nelson, Robert H. Brown, L. A. Soderblom, Giancarlo Bellucci, J. P. Bibring, M. Combes, Christophe Sotin, Fabrizio Capaccioni, R. Kursinski, Priscilla Cerroni, T. B. McCord, Vittorio Formisano, Pierre Drossart, Bruno Sicardy, Angioletta Coradini, P. D. Nicholson, Caitlin A. Griffith, Kevin H. Baines, Douglas M. Matson, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), US Geological Survey, Flagstaff, SETI Institute, NASA Ames Research Center, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Department of Earth and Space Sciences, University of Washington, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University
Subjects: 010504 meteorology & atmospheric sciences, Meteorology, Extraterrestrial Environment, Infrared, clouds, Atmospheric sciences, 01 natural sciences, Troposphere, symbols.namesake, 0103 physical sciences, VIMS, Spacecraft, 010303 astronomy & astrophysics, Optical depth, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, Spectrometer, Atmosphere, Spectrum Analysis, Satellites de Glace, Saturn, 13. Climate action, Middle latitudes, symbols, Cassini, Titan, Titan (rocket family), Longitude, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Methane, Geology
Abstract: International audience; Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal that the horizontal structure, height, and optical depth of Titan's clouds are highly dynamic. Vigorous cloud centers are seen to rise from the middle to the upper troposphere within 30 minutes and dissipate within the next hour. Their development indicates that Titan's clouds evolve convectively; dissipate through rain; and, over the next several hours, waft downwind to achieve their great longitude extents. These and other characteristics suggest that temperate clouds originate from circulation-induced convergence, in addition to a forcing at the surface associated with Saturn's tides, geology, and/or surface composition.
Published: 2005
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42. The Atmospheres of Saturn and Titan in the Near-Infrared First Results of Cassini/vims

Author: Kevin H. Baines, Roger N. Clark, Yves Langevin, Giancarlo Bellucci, Vittorio Formisano, Fabrizio Capaccioni, P. D. Nicholson, V. Mennella, Angioletta Coradini, D. P. Cruikshank, Robert M. Nelson, Caitlin A. Griffith, Robert H. Brown, T. B. McCord, C. Sotin, M. Combes, Jean-Pierre Bibring, B. J. Buratti, Tom Momary, Dennis L. Matson, Priscilla Cerroni, Pierre Drossart, R. Jaumann, Bruno Sicardy, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory, California Institute of Technology (JPL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), US Geological Survey, Flagstaff, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), SETI Institute, NASA Ames Research Center, Moffett Field, Department of Planetary Exploration, DLR, Department of Earth and Space Sciences, University of Washington, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University
Subjects: Haze, 010504 meteorology & atmospheric sciences, Atmospheric sciences, 01 natural sciences, law.invention, Troposphere, Atmosphere, symbols.namesake, Orbiter, Planet, law, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Near-Infrared, VIMS, Atmosphere of Titan, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Astronomy, Astronomy and Astrophysics, Satellites de Glace, Planetary science, Saturn, 13. Climate action, Space and Planetary Science, symbols, Cassini, Titan (rocket family), Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: International audience; The wide spectral coverage and extensive spatial, temporal, and phase-angle mapping capabilities of the Visual Infrared Mapping Spectrometer (VIMS) onboard the Cassini-Huygens Orbiter are producing fundamental new insights into the nature of the atmospheres of Saturn and Titan. For both bodies, VIMS maps over time and solar phase angles provide information for a multitude of atmospheric constituents and aerosol layers, providing new insights into atmospheric structure and dynamical and chemical processes. For Saturn, salient early results include evidence for phosphine depletion in relatively dark and less cloudy belts at temperate and mid-latitudes compared to the relatively bright and cloudier Equatorial Region, consistent with traditional theories of belts being regions of relative downwelling. Additional Saturn results include (1) the mapping of enhanced trace gas absorptions at the south pole, and (2) the first high phase-angle, high-spatial-resolution imagery of CH4 fluorescence. An additional fundamental new result is the first nighttime near-infrared mapping of Saturn, clearly showing discrete meteorological features relatively deep in the atmosphere beneath the planet's sunlit haze and cloud layers, thus revealing a new dynamical regime at depth where vertical dynamics is relatively more important than zonal dynamics in determining cloud morphology. Zonal wind measurements at deeper levels than previously available are achieved by tracking these features over multiple days, thereby providing measurements of zonal wind shears within Saturn's troposphere when compared to cloudtop movements measured in reflected sunlight. For Titan, initial results include (1) the first detection and mapping of thermal emission spectra of CO, CO2, and CH3D on Titan's nightside limb, (2) the mapping of CH4 fluorescence over the dayside bright limb, extending to ˜ ˜750 km altitude, (3) wind measurements of ˜ ˜0.5 ms-1, favoring prograde, from the movement of a persistent (multiple months) south polar cloud near 88° S latitude, and (4) the imaging of two transient mid-southern-latitude cloud features.
Published: 2005
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43. A 5-Micron-Bright Spot on Titan: Evidence for Surface Diversity

Author: Roger N. Clark, Michael E. Brown, Dale P. Cruikshank, Emily L. Schaller, Jason Perry, Angioletta Coradini, Thomas B. McCord, Alfred S. McEwen, Jason W. Barnes, Elizabeth P. Turtle, Bonnie J. Buratti, Robert H. Brown, Michael Janssen, Yves Langevin, J. Barbara, Henry G. Roe, P. D. Nicholson, Giancarlo Bellucci, Caitlin A. Griffith, Ralf Jaumann, Jean-Pierre Bibring, S. Fussner, Richard West, Christophe Sotin, Vittorio Formisano, Dennis L. Matson, Bruno Sicardy, M. Combes, Kevin H. Baines, Ralph D. Lorenz, Charles Elachi, Pierre Drossart, Fabrizio Capaccioni, A. H. Bouchez, Priscilla Cerroni, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Geological and Planetary Sciences, California Institute of Technology, Pasadena, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), US Geological Survey, Flagstaff, NASA Goddard Institute for Space Studies, Columbia University, W. M. Keck Observatory, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), SETI Institute, NASA Ames Research Center, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Department of Earth and Space Sciences, University of Washington, and Department of Astronomy, Cornell University
Subjects: Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Infrared, 01 natural sciences, Albedo feature, symbols.namesake, Optics, Dry Ice, 0103 physical sciences, VIMS, Geophysical Phenomena, Imaging science, Spacecraft, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, Spectrometer, Atmosphere, business.industry, Spectrum Analysis, Ice, Temperature, Water, Astronomy, Wavelength, Satellites de Glace, Saturn, Bright spot, infrared, symbols, Cassini, Titan, business, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Methane, Geology
Abstract: International audience; Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80°W and 20°S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena.
Published: 2005
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44. Cassini radar views the surface of Titan

Author: S. Vetrella, M. A. Janssen, L. Roth, Y. Anderson, Giovanni Picardi, Pierre Encrenaz, Duane O. Muhleman, Lauren Wye, Scott Hensley, Howard A. Zebker, Robert West, Laurence A. Soderblom, Roberto Seu, Enrico Flamini, S. D. Wall, Jonathan I. Lunine, Ellen R. Stofan, S. Shaffer, K. Kelleher, Matthew A. Allison, Yonggyu Gim, Philip S. Callahan, G. Hamilton, Rosaly M. C. Lopes, Giorgio Franceschetti, R. Boehmer, Francesco Posa, Charles A. Wood, William L. Johnson, Flora Paganelli, Steven J. Ostro, Randolph L. Kirk, Bryan Stiles, Ralph D. Lorenz, Charles Elachi, Elachi, C., Wall, S., Anderson, Y., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Franceschetti, Giorgio, Gim, Y., Hamilton, G., Hensley, S., Janssen, M., Johnson, W., Kelleher, K., Kirk, R., Lopes, R., Lorenz, R., Lunine, J., Muhleman, D., Ostro, S., Paganelli, F., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Soderblom, L., Stiles, B., Stofan, E., Vetrella, Sergio, West, R., Wood, C., Wye, L., Zebker, H., Jet Propulsion Laboratory, California Institute of Technology (JPL), Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Agenzia Spaziale Italiana (ASI), Facoltá di Ingegneria, US Geological Survey, Flagstaff, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Geological and Planetary Sciences, California Institute of Technology, Pasadena, Universitá La Sapienza, INFM and Dipartimento Interateneo di Fisica, Proxemy Research, Laytonsville, Planetary Science Institute, Tucson, and Stanford University
Subjects: Brightness, Extraterrestrial Environment, Volcanic Eruptions, law.invention, Atmosphere, symbols.namesake, Impact crater, law, Radar imaging, Emissivity, Radar, Organic Chemicals, Spacecraft, Remote sensing, Multidisciplinary, Ice, Temperature, Hydrocarbons, Saturn, Brightness temperature, symbols, Cassini, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Titan, Geology, radar
Abstract: International audience; The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of ~0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.
Published: 2005
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45. Principal components analysis of Jupiter VIMS spectra

Author: Ralf Jaumann, Yves Langevin, Bruno Sicardy, G. Hansen, P. D. Nicholson, Thomas B. McCord, Bonnie J. Buratti, Christophe Sotin, M.C. Chamberlain, Roger N. Clark, Vittorio Formisano, Jean-Pierre Bibring, Kevin H. Baines, Robert M. Nelson, Gianrico Filacchione, Mark R. Showalter, Priscilla Cerroni, Pierre Drossart, Emiliano D'Aversa, K. Hibbits, Giancarlo Bellucci, Robert H. Brown, Dennis L. Matson, Dale P. Cruikshank, Vito Mennella, Fabrizio Capaccioni, Angioletta Coradini, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), US Geological Survey, Flagstaff, SETI Institute, NASA Ames Research Center, Moffett Field, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Planetary Exploration, DLR, Department of Earth and Space Sciences, University of Washington, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Spectrometer, Channel (digital image), Wavelength range, Aerospace Engineering, Astronomy and Astrophysics, Stellar classification, 01 natural sciences, Spectral line, Jupiter, Satellites de Glace, Geophysics, Space and Planetary Science, 0103 physical sciences, Principal component analysis, General Earth and Planetary Sciences, Great Red Spot, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing
Abstract: International audience; During Cassini - Jupiter flyby occurred in December 2000, Visual-Infrared mapping spectrometer (VIMS) instrument took several image cubes of Jupiter at different phase angles and distances. We have analysed the spectral images acquired by the VIMS visual channel by means of a principal component analysis technique (PCA). The original data set consists of 96 spectral images in the 0.35-1.05 mum wavelength range. The product of the analysis are new PC bands, which contain all the spectral variance of the original data. These new components have been used to produce a map of Jupiter made of seven coherent spectral classes. The map confirms previously published work done on the Great Red Spot by using NIMS data. Some other new findings, presently under investigation, are presented.
Published: 2004
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46. The Cassini visual and infrared mapping spectrometer (VIMS) investigation

Author: R. M. Nelson, Jean-Pierre Bibring, P. D. Nicholson, Dale P. Cruikshank, P. Cerroni, Christophe Sotin, Roger N. Clark, V. Formisano, Robert H. Brown, G. Bellucci, T. B. McCord, D. L. Matson, R. Jaumann, Y. Langevin, F. Capaccioni, A. Coradini, B. J. Buratti, E. Miller, Pierre Drossart, Bruno Sicardy, Kevin H. Baines, Vito Mennella, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, biology, Spectrometer, Infrared, Observational techniques, Astronomy and Astrophysics, Venus, biology.organism_classification, 01 natural sciences, Astrobiology, symbols.namesake, Imaging spectroscopy, Satellites de Glace, Planetary science, 13. Climate action, Space and Planetary Science, 0103 physical sciences, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing, Saturnian system
Abstract: International audience; The Cassini visual and infrared mapping spectrometer (VIMS) investigation is a multidisciplinary study of the Saturnian system. Visual and near-infrared imaging spectroscopy and high-speed spectrophotometry are the observational techniques. The scope of the investigation includes the rings, the surfaces of the icy satellites and Titan, and the atmospheres of Saturn and Titan. In this paper, we will elucidate the major scientific and measurement goals of the investigation, the major characteristics of the Cassini VIMS instrument, the instrument calibration, and operation, and the results of the recent Cassini flybys of Venus and the Earth Moon system.
Published: 2004
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47. Enrichment in volatiles in the giant planets of the Solar System

Author: D. Gautier, Jonathan I. Lunine, Franck Hersant, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), and University of Arizona
Subjects: Jupiter, Physics, Solar System, Space and Planetary Science, Planet, Neptune, Gas giant, Uranus, Astronomy and Astrophysics, Formation and evolution of the Solar System, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Ice giant, Astrobiology
Abstract: International audience; We propose an interpretation of the enrichments in volatiles observed in the four giant planets with respect to the solar abundance. It is based on the assumption that volatiles were trapped in the form of solid clathrate hydrates and incorporated in planetesimals embedded in the feeding zones of each of the four giant planets. The mass of trapped volatiles is then held constant with time. The mass of hydrogen and of not trapped gaseous species continuously decreased with time until the formation of the planet was completed, resulting in an increase in the ratio of the mass of trapped volatiles to the mass of hydrogen (Gautier et al., Astrophys. J. 550 (2001) L227). The efficiency of the clathration depends upon the amount of ice available in the early feeding zone. The quasi-uniform enrichment in Ar, Kr, Xe, C, N, and S observed in Jupiter is reproduced because all volatiles were trapped. The non-uniform enrichment observed in C, N and S in Saturn is due to the fact that CH 4, NH 3, and H 2S were trapped but not CO and N 2. The non-uniform enrichment in C, N and S in Uranus and Neptune results from the trapping of CH 4, CO, NH 3 and H 2S, while N 2 was not trapped. Our scenario permits us to interpret the strongly oversolar sulfur abundance inferred by various modelers to be present in Saturn, Uranus and Neptune for reproducing the microwave spectra of the three planets. Abundances of Ar, Kr and Xe in these three are also predicted. Only Xe is expected to be substantially oversolar. The large enrichment in oxygen in Neptune with respect to the solar abundance, calculated by Lodders and Fegley (Icarus 112 (1994) 368) from the detection of CO in the upper troposphere of the planet, is consistent with the trapping of volatiles by clathration. The upper limit of CO in Uranus does not exclude that this process also occurred in Uranus.
Published: 2004
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48. CCD photometry, spin and shape model of the asteroid 1572 Posnania

Author: F. Colas, T. Kwiatkowski, Jérôme Berthier, W. Pych, Tadeusz Michalowski, Anders Erikson, Petr Pravec, Agnieszka Kryszczyńska, Wieslaw Z. Wisniewski, W. Borczyk, Adam Mickiewicz University in Poznań (UAM), Centrum Astronomiczne im. M. Kopernika, Warszawa (CAMK), Astronomy Institute of the Academy of Sciences, Ondrejov, Czech Republic, Institute of Space Sensor Technology and Planetary Exploration, Rutherford str. 2, 12489 Berlin, Germany, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Brightness, Ecliptic, Astronomy, Astronomy and Astrophysics, Astrophysics, Orbital period, Lambda, Photometry (optics), Amplitude, Space and Planetary Science, Asteroid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spin-½
Abstract: International audience; Lightcurves of the asteroid 1572 Posnania were obtained at six observatories on 19 nights during four apparitions: in 1993, 1994-95, 1996, and 1999. The synodical period is found to be 8.048 hours and the observed amplitudes of brightness variations are in the range of 0.37-0.40 mag. The sense of rotation is retrograde with a sidereal period Psid = 0.3353931 /- 0.0000003 days. The ecliptic coordinates of the pole of this asteroid are lambdap = 46deg /- 6deg and betap = -65deg /- 5deg. The shape of Posnania can be approximated by a triaxial ellipsoid model with semiaxes ratios a/b = 1.35 /- 0.01 and b/c = 1.04 /- 0.03. Partly based on observations collected at the European Southern Observatory, La Silla, Chile.
Published: 2001
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49. Simulation of the growth of the 3D Rayleigh-Taylor instability in supernova remnants using an expanding reference frame

Author: Romain Teyssier, Jean Ballet, A. Decourchelle, Federico Fraschetti, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Institute für Theoretische Physik, Universität Zürich, University of Zurich, and Fraschetti, F
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 530 Physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Mechanics, Astrophysics, Numerical diffusion, Shock (mechanics), Physics::Fluid Dynamics, Particle acceleration, Supernova, 1912 Space and Planetary Science, Space and Planetary Science, 10231 Institute for Computational Science, 3103 Astronomy and Astrophysics, Rayleigh–Taylor instability, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Ejecta, Supernova remnant, Astrophysics::Galaxy Astrophysics, Blast wave
Abstract: Context: The Rayleigh-Taylor instabilities generated by the deceleration of a supernova remnant during the ejecta-dominated phase are known to produce finger-like structures in the matter distribution which modify the geometry of the remnant. The morphology of supernova remnants is also expected to be modified when efficient particle acceleration occurs at their shocks. Aims: The impact of the Rayleigh-Taylor instabilities from the ejecta-dominated to the Sedov-Taylor phase is investigated over one octant of the supernova remnant. We also study the effect of efficient particle acceleration at the forward shock on the growth of the Rayleigh-Taylor instabilities. Methods: We modified the Adaptive Mesh Refinement code RAMSES to study with hydrodynamic numerical simulations the evolution of supernova remnants in the framework of an expanding reference frame. The adiabatic index of a relativistic gas between the forward shock and the contact discontinuity mimics the presence of accelerated particles. Results: The great advantage of the super-comoving coordinate system adopted here is that it minimizes numerical diffusion at the contact discontinuity, since it is stationary with respect to the grid. We propose an accurate expression for the growth of the Rayleigh-Taylor structures that connects smoothly the early growth to the asymptotic self-similar behaviour. Conclusions: The development of the Rayleigh-Taylor structures is affected, although not drastically, if the blast wave is dominated by cosmic rays. The amount of ejecta that makes it into the shocked interstellar medium is smaller in the latter case. If acceleration occurs at both shocks the extent of the Rayleigh-Taylor structures is similar but the reverse shock is strongly perturbed., Comment: 15 pages, 12 figures, accepted for publication in Astronomy and Astrophysics with minor editorial changes. Version with full resolution images can be found at http://www.lpl.arizona.edu/~ffrasche/~12692.pdf
Published: 2010
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50. CCD photometry and model of MUSES-C target (25143) 1998 SF36

Author: Kaasalainen, M., Kwiatkowski, T., Piironen, J., Dermawan, B., Farnham, T., Colas, F., Lowry, S., Weissman, P., Whiteley, R. J., Tholen, D. J., Larson, S. M., Toth, I., Velichko, F. P., Abe, Masanao, Nakamura, T., Ohba, Yohei, Yoshikawa, Makoto, Jakokoski Observatory, University of Helsinki, Astronomical Observatory, Adam Mickiewicz University, The Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan, National Astronomical Observatory of Japan (NAOJ), Graduate School of Science, University of Tokyo, Department of Astronomy, University of Texas, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory, California Institute of Technology (JPL), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Institute for Astronomy, University of Hawaii, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, and Astronomical Institute of Kharkov National University
Subjects: Rotation period, Physics, 010504 meteorology & atmospheric sciences, Astronomy, Astronomy and Astrophysics, Astrophysics, Lambda, 01 natural sciences, Photometry (optics), Space and Planetary Science, Asteroid, Sidereal time, 0103 physical sciences, Elongation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: 著者人数: 17名, Accepted: 2003-05-31, 資料番号: SA1003348000
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