Interior thermal state of Enceladus inferred from the viscoelastic state of the ice shell

Recent geodetic measurements for Enceladus suggest a global subsurface ocean that is thicker beneath the south pole. In order to maintain such an ocean, viscous relaxation of topography at the base of the ice shell and melting of ice need to be balanced. In this study, we investigate the interior th...

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Bibliographic Details
Published in:Icarus
Main Authors: Kamata, Shunichi, Nimmo, Francis
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier
Subjects:
450
Online Access:http://hdl.handle.net/2115/72823
https://doi.org/10.1016/j.icarus.2016.11.034
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Summary:Recent geodetic measurements for Enceladus suggest a global subsurface ocean that is thicker beneath the south pole. In order to maintain such an ocean, viscous relaxation of topography at the base of the ice shell and melting of ice need to be balanced. In this study, we investigate the interior thermal state that can lead to the relaxation timescale being comparable to the melting timescale. Our results indicate that a basal heat flux about ten times higher than that due to radiogenic heating, or an ice shell tidal heating rate about ten times higher than the conventional estimate of 1.1 GW is necessary if the ice shell is in thermal equilibrium. These requirements are concordant with recent astrometric studies.