Thermal Equilibrium States of Europa's Ice Shell: Implications for Internal Ocean Thickness and Surface Heat Flow |
| |
| Authors: | Hauke HussmannTilman Spohn Karin Wieczerkowski |
| |
| Institution: | a Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm Klemm Str. 10, Münster, D-48149, Germanyf1hhussman@uni-muenster.def1b GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, D-14473, Germany |
| |
| Abstract: | Ice-shell thickness and ocean depth are calculated for steady state models of tidal dissipation in Europa's ice shell using the present-day values of the orbital elements. The tidal dissipation rate is obtained using a viscoelastic Maxwell rheology for the ice, the viscosity of which has been varied over a wide range, and is found to strongly increase if an (inviscid) internal ocean is present. To determine steady state values, the tidal dissipation rate is equated to the heat-transfer rate through the ice shell calculated from a parameterized model of convective heat transfer or from a thermal conduction model, if the ice layer is found to be stable against convection. Although high dissipation rates and heat fluxes of up to 300 mWm−2 are, in principle, possible for Europa, these values are unrealistic because the states for which they are obtained are thermodynamically unstable. Equilibrium models have surface heat flows around 20 mWm−2 and ice-layer thicknesses around 30 km, which is significantly less than the total thickness of the H2O-layer. These results support models of Europa with ice shells a few tens of kilometers thick and around 100-km-thick subsurface oceans. |
| |
| Keywords: | Europa |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
