The Atmospheres of Saturn and Titan in the Near-Infrared First Results of Cassini/vims

• Published in: Earth, Moon, and Planets
• Main Authors: Baines, Kevin H., Drossart, Pierre, Momary, Thomas W., Formisano, Vittorio, Griffith, Caitlin A., Bellucci, Giancarlo, Bibring, Jean-Pierre, Brown, Robert H., Buratti, B. J., Capaccioni, Fabrizio, Cerroni, Priscilla, Clark, Roger N., Coradini, Angioletta, Combes, Michel, Cruikshank, Dale P., Jaumann, Ralf, Langevin, Yves, Matson, Dennis L., Mccord, Thomas B., Mennella, Vito, Nelson, Robert M., Nicholson, Philip D., Sicardy, Bruno, Sotin, Christophe
• Other Authors: Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), 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, 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), Department of Astronomy, Cornell University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; South Pole; South pole
• Online Access: https://hal.science/hal-03797087; https://doi.org/10.1007/s11038-005-9058-2

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 CH 4 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, CO 2 , and CH 3 D on Titan's nightside limb, (2) the mapping of CH 4 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) ...