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Start Over Descriptor "Satellites de Glace" Topic 0105 earth and related environmental sciences
19 results on '"Satellites de Glace"'

1. Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

Author

Robert M. Nelson, Kevin H. Baines, Ralf Jaumann, Angioletta Coradini, Christophe Sotin, Bruno Sicardy, Fabrizio Capaccioni, Mark R. Showalter, Dale P. Cruikshank, Caitlin A. Griffith, Pierre Drossart, Robert H. Brown, B. J. Buratti, Yves Langevin, Dennis L. Matson, Vito Mennella, Charles A. Hibbitts, Roger N. Clark, Priscilla Cerroni, Vittorio Formisano, Giancarlo Bellucci, P. D. Nicholson, Gary B. Hansen, N. Baugh, Tom Momary, Thomas B. McCord, 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 Planetary Sciences, and Lunar and Planetary Laboratory, University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Consiglio Nazionale delle Ricerche, Isituto di Fisica dello Spazio Interplanetario, Via Fosso del Cavaliere, Consiglio Nazionale delle Ricerche, Isituto di Astrofisica Spaziale, via Fosso del Cavaliere, US Geological Survey, Denver, SETI Institute, NASA Ames Research Center, Moffett Field, 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), Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, 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, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University

Subjects
Solar System, 010504 meteorology & atmospheric sciences, Infrared, Rings of Saturn, Astrophysics, 01 natural sciences, symbols.namesake, Impact crater, 0103 physical sciences, VIMS, Atmosphere of Titan, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Spectrometer, Astronomy, Astronomy and Astrophysics, solar system, Satellites de Glace, Saturn, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Absorption band, infrared, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family)
Abstract

International audience; The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO{2}, and ferrous iron. Iapetus contains CO{2} and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be CO{2} and CH{3}D. As determined from cloud motions, the winds at altitude 25-30 km in the south polar region of Titan appear to be moving in a prograde direction at velocity ˜ 1 m s-1. Circular albedo features on Titan's surface, seen at 2.02 mu m, may be palimpsests remaining from the rheological adjustment of ancient impact craters. As such, their long-term persistence is of special interest in view of the expected precipitation of liquids and solids from the atmosphere. Saturn's rings have changed little in their radial structure since the Voyager flybys in the early 1980s. Spectral absorption bands tentatively attributed to Fe2+ suggest that iron-bearing silicates are a source of contamination of the C ring and the Cassini Division.

Published
2006
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2. Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan

Author

S. Lemouelic, P. D. Nicholson, Angioletta Coradini, Katrin Stephan, L. A. Soderblom, C.K. Scholz, Priscilla Cerroni, Yves Langevin, Giancarlo Bellucci, Robert H. Brown, Kevin H. Baines, Dale P. Cruikshank, Vittorio Formisano, Sebastien Rodriguez, Robert M. Nelson, Christophe Sotin, Pierre Drossart, Ralf Jaumann, Thomas B. McCord, Dennis L. Matson, Bruno Sicardy, Fabrizio Capaccioni, Bonnie J. Buratti, Jean-Pierre Bibring, M. Combes, Roger N. Clark, 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 (JPL), NASA-California Institute of Technology (CALTECH), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Institut d'astrophysique spatiale (IAS), 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), 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), NASA Ames Research Center (ARC), Department of Earth and Space Sciences [Seattle], and University of Washington [Seattle]

Subjects
Solar System, Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Infrared Rays, Infrared, cryovolcanism, Saturnian satellites, near-infrared, 01 natural sciences, Methane, Astrobiology, symbols.namesake, chemistry.chemical_compound, 0103 physical sciences, Photography, VIMS, Spacecraft, Atmosphere of Titan, Moon, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, Multidisciplinary, Life on Titan, geography.geographical_feature_category, Geography, Atmosphere, Ice, Cryovolcano, Hydrocarbons, Satellites de Glace, Saturn, Volcano, chemistry, 13. Climate action, symbols, Environmental science, Cassini, Gases, Titan, Titan (rocket family)
Abstract

The surface of Saturn's largest moon, Titan, is coated in a dense methane-rich atmosphere that prevents high-resolution imaging at visible wavelengths. During its first Titan flyby last October, the Cassini spacecraft's visual and infrared mapping spectrometer (VIMS) was able to reveal detailed surface structures, as reported in this issue. Notable features include a circular structure 30 km in diameter, thought to be a cryogenic dome. This may be volcanic, which could explain how the methane in Titan's atmosphere is replenished. Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component2, but it is photodissociated on a timescale of 107 years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons4,5 to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure ∼30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.

Published
2005
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3. 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 “tiger stripes.” 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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4. Photometric properties of Titan's surface from Cassini VIMS : Relevance to titan's hemispherical albedo dichotomy and surface stability

Author

Kevin H. Baines, L. W. Kamp, P. D. Nicholson, Christophe Sotin, M. Combes, Giancarlo Bellucci, Thomas B. McCord, Bruce Hapke, Dale P. Cruikshank, Fabrizio Capaccioni, Pierre Drossart, William D. Smythe, Roger N. Clark, M. D. Boryta, Ralf Jaumann, Vittorio Formisano, Robert M. Nelson, Robert H. Brown, Jean-Pierre Bibring, Vito Mennella, Bruno Sicardy, B. J. Buratti, Yves Langevin, Dennis L. Matson, Priscilla Cerroni, F. Leader, 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), Jet Propulsion Laboratory, California Institute of Technology (JPL), University of Arizona, University of Pittsburgh, Mount San Antonio College, Walnut, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Université Paris-Sud - Paris 11 (UP11), US Geological Survey, Denver, 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), National Aeronautics and Space Administration, Ames Research Center, Department of Planetary Exploration, DLR, University of Hawaii, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Department of Astronomy, Cornell University, and Université de Nantes (UN)

Subjects
Brightness, medicine.medical_specialty, Haze, 010504 meteorology & atmospheric sciences, Astrophysics, 01 natural sciences, Astrobiology, law.invention, Orbiter, symbols.namesake, Impact crater, law, 0103 physical sciences, medicine, Specular reflection, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astronomy and Astrophysics, Spectral imaging, Satellites de Glace, 13. Climate action, Space and Planetary Science, symbols, Titan (rocket family), Longitude, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract

International audience; The Visual and Infrared Mapping Spectrometer (VIMS) instrument on the Cassini Saturn Orbiter returned spectral imaging data as the spacecraft undertook six close encounters with Titan beginning 7 July, 2004. Three of these flybys each produced overlapping coverage of two distinct regions of Titan's surface. Twenty-four points were selected on approximately opposite hemispheres to serve as photometric controls. Six points were selected in each of four reflectance classes. On one hemisphere each control point was observed at three distinct phase angles. From the derived phase coefficients, preliminary normal reflectances were derived for each reflectance class. The normal reflectance of Titan's surface units at 2.0178 mum ranged from 0.079 to 0.185 for the most absorbing to the most reflective units assuming no contribution from absorbing haze. When a modest haze contribution of tau=0.1 is considered these numbers increase to 0.089-0.215. We find that the lowest three reflectance classes have comparable normal reflectance on either hemisphere. However, for the highest brightness class the normal reflectance is higher on the hemisphere encompassing longitude 14-65° compared to the same high brightness class for the hemisphere encompassing 122-156° longitude. We conclude that an albedo dichotomy observed in continental sized units on Titan is due not only to one unit having more areal coverage of reflective material than the other but the material on the brighter unit is intrinsically more reflective than the most reflective material on the other unit. This suggests that surface renewal processes are more widespread on Titan's more reflective units than on its less reflective units. We note that one of our photometric control points has increased in reflectance by 12% relative to the surrounding terrain from July of 2004 to April and May of 2005. Possible causes of this effect include atmospheric processes such as ground fog or orographic clouds; the suggestion of active volcanism cannot be ruled out. Several interesting circular features which resembled impact craters were identified on Titan's surface at the time of the initial Titan flyby in July of 2004. We traced photometric profiles through two of these candidate craters and attempted to fit these profiles to the photometric properties expected from model depressions. We find that the best-fit attempt to model these features as craters requires that they be unrealistically deep, approximately 70 km deep. We conclude that despite their appearance, these circular features are not craters, however, the possibility that they are palimpsests cannot be ruled out. We used two methods to test for the presence of vast expanses of liquids on Titan's surface that had been suggested to resemble oceans. Specular reflection of sunlight would be indicative of widespread liquids on the surface; we found no evidence of this. A large liquid body should also show uniformity in photometric profile; we found the profiles to be highly variable. The lack of specular reflection and the high photometric variability in the profiles across candidate oceans is inconsistent with the presence of vast expanses of flat-lying liquids on Titan's surface. While liquid accumulation may be present as small, sub-pixel-sized bodies, or in areas of the surface which still remain to be observed by VIMS, the presence of large ocean-sized accumulations of liquids can be ruled out. The Cassini orbital tour offers the opportunity for VIMS to image the same parts of Titan's surface repeatedly at many different illumination and observation geometries. This creates the possibility of understanding the properties of Titan's atmosphere and haze by iteratively adapting models to create a best fit to the surface reflectance properties.

Published
2006
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5. Cassini observations of flow-like features in western Tui Regio, Titan

Author

Bonnie J. Buratti, Jason Perry, Jani Radebaugh, Jason W. Barnes, Roger N. Clark, Sebastien Rodriguez, P. D. Nicholson, Elizabeth P. Turtle, Kevin H. Baines, Christophe Sotin, Stéphane Le Mouélic, Robert H. Brown, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Spectrometer, Infrared, Astronomy, Geophysics, 01 natural sciences, Flow field, Satellites de Glace, symbols.namesake, [SDU]Sciences of the Universe [physics], 13. Climate action, 0103 physical sciences, symbols, General Earth and Planetary Sciences, Imaging science, Titan (rocket family), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

[1] A large (>3 × 104 km2), lobate, 5-μm-bright region seen by Cassini on Titan's leading equatorial region is best explained as a flow field. We discuss observations from the Visual and Infrared Mapping Spectrometer and Imaging Science Subsystem of the feature and present a map of the field. We establish relative ages of flow features and discuss possible formation mechanisms and the implications of this finding for the evolution of Titan's surface.

Published
2006
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6. 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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7. 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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8. Titan's internal structure inferred from a coupled thermal-orbital model

Author

Jonathan I. Lunine, Olivier Grasset, Gabriel Tobie, Christophe Sotin, Antoine Mocquet, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, Solar System, 010504 meteorology & atmospheric sciences, Ice Ih, Orbital eccentricity, 01 natural sciences, 7. Clean energy, Astrobiology, symbols.namesake, 0103 physical sciences, Thermal, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Mechanics, Dissipation, Satellites de Glace, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Heat transfer, symbols, Astrophysics::Earth and Planetary Astrophysics, Titan (rocket family)
Abstract

Through coupled thermal and orbital calculations including a full description of tidal dissipation, heat transfer and the H 2O–NH3 phase diagram, we propose a model for the internal structure and composition of Titan testable with Cassini–Huygens measurements. The high value of Titan’s orbital eccentricity provides a strong constraint on the amount of the tidal energy dissipation on its surface and within its interior since its formation. We show that only models with a few percent of ammonia (and not zero) in the primordial liquid water shell can limit the damping of the eccentricity over the age of the Solar System. The present models predict that a liquid ammonia-rich water layer should still be present within Titan under an ice I layer, a few tens of kilometers thick. Furthermore, we predict that any event linked to convective processes in the ice Ih layer (like the degassing of methane) could have occurred very late in Titan’s history.

Published
2005

9. 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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10. Tidal dissipation within large icy satellites : Applications to Europa and Titan

Author

Christophe Sotin, Gabriel Tobie, Antoine Mocquet, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Meteorology, Tidal heating, 7. Clean energy, 01 natural sciences, Mantle (geology), Viscoelasticity, Physics::Geophysics, chemistry.chemical_compound, symbols.namesake, 0103 physical sciences, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, business.industry, Astronomy and Astrophysics, Geophysics, Dissipation, Strain rate, Silicate, Satellites de Glace, chemistry, 13. Climate action, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, business, Titan (rocket family), Tidal power
Abstract

This paper describes a new approach based on variational principles to calculate the radial distribution of tidal energy dissipation in any satellite. The advantage of the model with respect to classical solutions, is that it relates in a straightforward way the radial distribution of the time-averaged dissipation rate to its sensitivity to the corresponding distribution of viscoelastic parameters. This method is applied to Io-, Europa-, and Titan-like interiors, and it is tested against the results obtained by two classical methods by determining global dissipation as well as radial and lateral distributions within satellite interiors. By exploring systematically the different parameters defining the interior models, we demonstrate that the presence of a deep ocean below an outer ice layer strongly influences the tidal dissipation distribution in both the outer ice layer and in the innermost part of the satellite. On the one hand, the ocean by imposing a large radial displacement at the base of the outer ice I layer, controls the distribution of tidal strain rate within the outer layer, making the tidal strain rate field very weakly sensitive to the viscosity variations. Conversely, in the high-pressure ice layer below the ocean, both tidal strain rate and dissipation are very sensitive to any variation of the ice viscosity. On the other hand, for identical structures of the mantle and of the core, the presence of a subsurface ocean reduces the strength of dissipation in the silicate mantle. The existence of a liquid layer within Europa makes models of the silicate mantle less dissipative than the predictions for Io.

Published
2005

11. Pressure measurements within optical cells using diamond sensors: accuracy of the method below 1GPa

Author

M. Choukroun, E. Amiguet, O. Grasset, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Analytical chemistry, 02 engineering and technology, engineering.material, 01 natural sciences, Diamond anvil cell, law.invention, symbols.namesake, law, Dispersion (optics), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Chemistry, Diamond, Gauge (firearms), Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Satellites de Glace, Pressure measurement, Sapphire, engineering, symbols, Atomic physics, 0210 nano-technology, Raman spectroscopy
Abstract

The accuracy of the diamond pressure gauge has been investigated in the moderate pressure range (0–1 GPa) between 210 and 310 K. Experiments have been conducted using a sapphire anvil cell coupled to a Raman spectrometer. The temperature shift of the first-order Raman peak of diamond is very small (−7.56×10−4 cm−1/K−1.5), which confirms previous results obtained on a wider temperature range. Such a trend implies a very small shift over the studied temperature range, of the same order than the dispersion due to external factors (isotopic composition, orientation). The pressure dependence is found equal to 3.20 (±0.02) cm−1/GPa. A statistical description of the data is provided, indicating that the diamond gauge provides pressure estimates below 1 GPa with an accuracy of±39 MPa. Application of these results to science fields involved in the moderate pressure range below 1 GPa is discussed.

Published
2005

12. Compositional maps of Saturn's moon Phoebe from imaging spectroscopy

Author

Jean-Pierre Bibring, P. D. Nicholson, Fabrizio Capaccioni, Angioletta Coradini, Vito Mennella, Jonathan I. Lunine, Bonnie J. Buratti, Yves Langevin, Bruno Sicardy, Robert M. Nelson, Todd M. Hoefen, Robert H. Brown, Thomas B. McCord, Kevin H. Baines, Priscilla Cerroni, Dale P. Cruikshank, Vittorio Formisano, Christophe Sotin, Ralf Jaumann, Dennis L. Matson, Giancarlo Bellucci, Gary B. Hansen, Klaus-Dieter Matz, J. M. Curchin, Roger N. Clark, Karl Hibbits, 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), 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
Solar System, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Saturnian satellites, imaging spectroscopy, 01 natural sciences, Astrobiology, Saturn's Moon Phoebe, Saturn, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Circular orbit, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, Retrograde motion, Astronomy, Imaging spectroscopy, Satellites de Glace, Phoebe, 13. Climate action, Physics::Space Physics, Cassini, Satellite, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract

The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed. By contrast, Saturn's regular satellites (with prograde, low-inclination, circular orbits) probably accreted within the sub-nebula in which Saturn itself formed. Here we report imaging spectroscopy of Phoebe resulting from the Cassini-Huygens spacecraft encounter on 11 June 2004. We mapped ferrous-iron-bearing minerals, bound water, trapped CO2, probable phyllosilicates, organics, nitriles and cyanide compounds. Detection of these compounds on Phoebe makes it one of the most compositionally diverse objects yet observed in our Solar System. It is likely that Phoebe's surface contains primitive materials from the outer Solar System, indicating a surface of cometary origin.

Published
2005
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13. Resorption process in Astypalaea Linea extensive region (Europa)

Author

E. Mercier, Loïc Mével, 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), and Programme National de Planétologie, INSU

Subjects
Morphology, 010504 meteorology & atmospheric sciences, Galileo, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Linea, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, Compression (geology), Petrology, 010303 astronomy & astrophysics, Process (anatomy), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Icy satellites, Tectonics, Compression, Astronomy and Astrophysics, Crust, Geophysics, 91.10.Kg, 96.12.-a, 96.12.Xy, 96.30.ld, 91.55.Nc, Satellites de Glace, Space and Planetary Science, Astypalaea Linea, Europa, Geology
Abstract

International audience; Whereas numerous extensive features, where new crust is created, are now well recognized on Europa's surface, those relevant to crust disappearance remain difficult to find. This work presents a reconstruction of the surface prior to Astypalaea Linea's emplacement (one of the features where new crustal material appears). We demonstrate that a scattered disappearance of crust takes place in an extensive region close to Astypalaea Linea. Physical processes invoked for disappearance are discussed: pressure melting may be responsible for the mobilization of surface material and its collapse down through the icy crust.

Published
2005
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14. A comparative study of the outer planets before the exploration of Saturn by Cassini/Huygens ; Introduction

Author

Encrenaz, Thérèse, Kallenbach, R., Owen, Tobias C., Sotin, Christophe, 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), 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), International Space Science Institute (ISSI), and University of Hawaii, Manoa

Subjects
Satellites de Glace, 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience; Not Available

Published
2005
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15. Cassini VIMS observations of the Galilean satellites including the VIMS calibration procedure

Author

Jean-Pierre Bibring, Angioletta Coradini, Yves Langevin, G. B. Hansen, Gianrico Filacchione, P. D. Nicholson, Priscilla Cerroni, Robert M. Nelson, M. Combes, Pierre Drossart, Kevin H. Baines, Bonnie J. Buratti, Fabrizio Capaccioni, Giancarlo Bellucci, Dennis L. Matson, Charles A. Hibbitts, Roger N. Clark, Dale P. Cruikshank, Vittorio Formisano, Robert H. Brown, Thomas B. McCord, Bruno Sicardy, E. Bussoletti, Christophe Sotin, 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), HIGP/SOEST, University of Hawaii, Istituto Fisica Spazio Interplanetario, INAF, Planetary Science Institute, 22 Fiddler's Rd., Winthrop, Istituto Astrofisica Spaziale e Fisica Cosmica, CNR, US Geological Survey, Denver, Department Planetary Science and LPL, University of AZ, Tucson, 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), INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), 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, Department of Planetary Exploration, DLR, Department of Astronomy, Cornell University, and Université de Nantes (UN)

Subjects
010504 meteorology & atmospheric sciences, Satellite surfaces, 01 natural sciences, Space mission, Jovian, Jupiter, symbols.namesake, Saturn, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing, Spectrometer, Spacecraft, business.industry, Near-infrared spectroscopy, Astronomy, Astronomy and Astrophysics, Galilean satellites, Galilean moons, Satellites de Glace, 13. Climate action, Space and Planetary Science, Surface composition, Physics::Space Physics, symbols, Astrophysics::Earth and Planetary Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Jupiter system, Geology, Data reduction
Abstract

The Visual and Infrared Mapping Spectrometer (VIMS) observed the Galilean satellites during the Cassini spacecraft's 2000/2001 flyby of Jupiter, providing compositional and thermal information about their surfaces. The Cassini spacecraft approached the jovian system no closer than about 126 Jupiter radii, about 9 million kilometers, at a phase angle of

Published
2004
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16. 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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17. 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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18. Internal structure and dynamics of the large icy satellites

Author

Gabriel Tobie, Christophe Sotin, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, General Engineering, Energy Engineering and Power Technology, Glacier, Tidal heating, Icy moon, 01 natural sciences, Astrobiology, Galilean moons, symbols.namesake, Satellites de Glace, 13. Climate action, Saturn, 0103 physical sciences, symbols, Titan (rocket family), Internal heating, 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The magnetic data returned by the Galileo mission suggest that deep oceans are present within the icy Galilean satellites. In addition, tectonic features on Europa are consistent with models of subsolidus convection within the outer ice I layer. Ice viscosity is a key parameter for modeling the thermal and orbital evolution of these large satellites. Using laboratory experiments and glacier measurements, this article shows that tidal heating is a strong source of internal heating which may explain the presence of a deep ocean within Europa. Another key parameter is the composition of ice. The presence of ammonia, which is likely in Saturn's sub-nebula, decreases so much the melting point temperature of ice that it would inhibit the complete freezing of the ocean. Predictions for the internal structure of Titan are made and will be checked by the Cassini mission which started orbiting Saturn on 1st July 2004. To cite this article: C. Sotin, G. Tobie, C. R. Physique 5 (2004).

Published
2004

19. Tidally heated convection : Constraints on Europa's ice shell thickness

Author

Gaël Choblet, Gabriel Tobie, Christophe Sotin, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, Atmospheric Science, 010504 meteorology & atmospheric sciences, Convective heat transfer, Equator, ice, Soil Science, Tidal heating, Aquatic Science, Pressure ridge, Oceanography, 01 natural sciences, Physics::Geophysics, Physics::Fluid Dynamics, Sea ice growth processes, Geochemistry and Petrology, 0103 physical sciences, 5770 Planetology: Fluid Planets: Tidal forces, Earth and Planetary Sciences (miscellaneous), 6218 Planetology: Solar System Objects: Jovian satellites Europa, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Ecology, Paleontology, 6020 Planetology: Comets and Small Bodies: Ice, Forestry, Geophysics, equilibrium thickness, tidal dissipation, Satellites de Glace, Heat flux, 13. Climate action, Space and Planetary Science, thermal convection, [SDU]Sciences of the Universe [physics], Heat transfer, 5418 Planetology: Solid Surface Planets: Heat flow, Astrophysics::Earth and Planetary Astrophysics, 5430 Planetology: Solid Surface Planets: Interiors (8147), Geology
Abstract

International audience; The thickness of Europa's ice shell is constrained with numerical experiments of thermal convection, including heterogeneous tidal heating. Thermal convection occurs in the stagnant lid regime with most of the tidal heating located in the bottom half of the layer. The addition of tidal heating mainly results in the increase of the temperature of the well-mixed interior and in the decrease of the heat flux at the base of the ice layer. In many simulations, the ice in hot plumes is heated up to its melting point. This induces episodic upwellings (0.5 Ma) of partially molten ice up to the base of the conductive lid, with possible implications for the formation of lenticulae and chaos regions. The thickness of the convective ice shell in equilibrium with the heat flow from the silicate core is estimated to be about 20-25 km. Tidal dissipation and surface temperature variations create lateral variations of the ice shell thickness of about 5 km, with maxima near the equator at the Jovian and anti-Jovian points and minima at midlatitudes. Surface heat flux is about 35-40 mW.m À2 ; it is almost constant all over Europa's surface, even though the tidal dissipation rate is four times larger at the poles than at the equator.

Published
2003
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