Mimas, Enceladus, Tethys, Dione: contrasting geological paths for Saturn's inner icy moons
Abstract
A recent model involving a dissipative porous core within Enceladus (Choblet et al., 2017) succeeds at explaining the main features inferred from the Cassini mission in terms of internal structure (global ocean beneath a very uneven ice shell, porous core) as well as composition (ocean is salty, deep hydrothermal activity occurs at present). In this regard, Enceladus (E) could be in a global steady-state where internal heat produced deep in the interior is transmitted to the surface leading to the observed activity at present.
As the other inner mid-sized moons of Saturn (M, T and D: Mimas, Tethys and Dione) have also all been suggested to harbour/have harboured a subsurface ocean, their interior could have/have had the same structure than that inferred for E. Note that in the case of M, this ocean could exist at present (observed libration, Tajeddine et al. 2014) while for T and D, this possibility is inferred from geological arguments (modelled crater relaxation, White et al., 2017) and thus could correspond to a period in the past. We thus ask the question whether these three other moons present a similar global equilibrium where surface geology reflects present-day interior heat budget. Assuming an internal structure similar to that of E and comparable material properties, we evaluate the tidal dissipation budget of M, T and D for their present-day orbital characteristics.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P33A..01C
- Keywords:
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- 4850 Marine organic chemistry;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGYDE: 6282 Enceladus;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 8450 Planetary volcanism;
- VOLCANOLOGY