Evolution of Icy Satellites

• Published in: Space Science Reviews
• Main Authors: Schubert, Gerald, Hussmann, Hauke, Lainey, Valéry, Matson, Dennis L., Mckinnon, W. B., Sohl, Frank, Sotin, Christophe, Tobie, Gabriel, Turrini, Diego, van Hoolst, Tim
• Other Authors: Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics (IGPP/UCLA), Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, 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, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Earth and Planetary Sciences, Washington University, Washington University in Saint Louis (WUSTL), Université de Nantes (UN), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy, Royal Observatory of Belgium = Observatoire Royal de Belgique (ROB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; South Pole; Jupiter; Laplace; Phoebe; Ganymede; South pole
• Online Access: https://hal.science/hal-03743069; https://doi.org/10.1007/s11214-010-9635-1

International audience Evolutionary scenarios for the major satellites of Jupiter, Saturn, Neptune, and Pluto-Charon are discussed. In the Jovian system the challenge is to understand how the present Laplace resonance of Io, Europa, and Ganymede was established and to determine whether the heat being radiated by Io is in balance with the present tidal dissipation in the moon. In the Saturnian system, Enceladus and Titan are the centers of attention. Tidal heating is the likely source of activity at the south pole of Enceladus, although the details of how the heating occurs are not understood. An evolutionary scenario based on accretion and internal differentiation is presented for Titan, whose present substantial orbital eccentricity is not associated with any dynamical resonance. The source and maintenance of methane in Titan's present atmosphere remain uncertain. Though most attention on the Saturnian moons focuses on Titan and Enceladus, the mid-size satellites Iapetus, Rhea, Tethys, and the irregular satellite Phoebe also draw our interest. An evolutionary scenario for Iapetus is presented in which spin down from an early rapidly rotating state is called upon to explain the satellite's present oblate shape. The prominent equatorial ridge on Iapetus is unexplained by the spin down scenario. A buckling instability provides another possible explanation for the oblateness and equatorial ridge of Iapetus. Rhea is the only medium-size Saturnian satellite for which there are gravity data at present. The interpretation of these data are uncertain, however, since it is not known if Rhea is in hydrostatic equilibrium. Pluto and Charon are representative of the icy dwarf planets of the Kuiper belt. Did they differentiate as they evolved, and do either of them have a subsurface liquid water ocean? New Horizons might provide some answers when it arrives at these bodies.