Viscoelastic relaxation of Enceladus’s ice shell

•We propose a dynamic explanation of non-hydrostatic topography on Enceladus.•Evolution of the topography is governed by viscoelastic deformation.•The present-day shape of the ice shell ultimately depends on loading history.•Viscoelastic relaxation of the moon is slow compared to large icy satellite...

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Veröffentlicht in:Icarus (New York, N.Y. 1962) N.Y. 1962), 2017-07, Vol.291, p.31-35
Hauptverfasser: Čadek, Ondřej, Běhounková, Marie, Tobie, Gabriel, Choblet, Gaël
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Sprache:eng
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Zusammenfassung:•We propose a dynamic explanation of non-hydrostatic topography on Enceladus.•Evolution of the topography is governed by viscoelastic deformation.•The present-day shape of the ice shell ultimately depends on loading history.•Viscoelastic relaxation of the moon is slow compared to large icy satellites.•Low degree topography is consistent with a reduction of ice roots in the past. We propose a dynamic model relating the non-hydrostatic long-wavelength topography on Enceladus to loading at the base of the ice shell. In dynamic equilibrium, the surface topography induced by a bottom load is very close to that inferred for Airy isostasy. However, due to the small size of the moon the relaxation to equilibrium is significantly longer than the maximum Maxwell relaxation time. During the relaxation, the upper load/bottom load ratio can be either smaller than 1 or larger than 1, depending on the initial state and the loading history.
ISSN:0019-1035
1090-2643
DOI:10.1016/j.icarus.2017.03.011