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| Titel |
Thermal stability of internal liquid water reservoir at Enceladus' South pole |
| VerfasserIn |
Marie Behounkova, Gabriel Tobie, Jonathan Besserer, Ondrej Cadek, Gael Choblet |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048125
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| Zusammenfassung |
| The total heat power released at Enceladus’ South pole is about 50 times larger than the
available radiogenic power, implying that an additional source of energy exists. Tidal
dissipation is the most likely candidate, but the observed power and its particular location at
the south pole can be reproduced only if a liquid layer exists at depth (Tobie et al. Icarus
2008). Moreover, this liquid reservoir should spread over at least half of the southern
hemisphere to induce sufficient tidal deformation at the pole. In order to determine the
stability of this internal liquid reservoir and its effects on the dynamics of the overlying ice
shell, we have developed a new tool that solves simultaneously mantle convection
and tidal dissipation in 3D spherical geometry (BÄhounková et al. JGR, 2010).
Using this new 3D technique, we demonstrate that the tidal strain rates are strongly
enhanced in hot upwellings when compared with classical methods of tidal dissipation
computation, and therefore that lateral variations of viscosity must be explicitly taken into
account to correctly describe the dissipation field. Moreover, our 3D simulations
show that tidal dissipation in Enceladus tends to focus hot upwellings at the South
pole and cold downwellings in the equatorial region, and that the heat flux at the
base of the ice shell is strongly reduced at the pole, thus favoring the preservation
of a liquid reservoir at depth. By systematically varying the orbital and internal
parameters, we investigate the conditions under which a liquid reservoir can be
thermally stable in Enceladus’ interior and what is its possible extension at equilibrium. |
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