Meeting Reports

Abstract

Cassini measurements of Mimas' physical libration can be explained by either a non-hydrostatic core or a global, liquid water ocean beneath a 24–31 km thick ice shell. An ocean within Mimas would be surprising, given the lack of comparable geologic activity to that observed on other ocean-bearing moons like Europa and Enceladus, and thus has important implications for the prevalence and identification of ocean worlds. Here, we calculate the tidal heating that would be generated within an ocean-bearing Mimas and determine the ice shell thicknesses that would result. Our model accounts for tidal heating caused by Mimas' eccentricity and libration and uses a depth-dependent rheological profile in the ice. We find that the ability of Mimas to host a 24–31 km ice shell over an ocean depends on the rheology of the ice, the surface temperature, and the basal heat flux. We find that, using the most reasonable assumptions, Mimas would have the suggested ocean and ice shell thicknesses today. We report corresponding average surface heat fluxes for these cases and discuss observational data that could further assess whether Mimas is, indeed, a present-day ocean world.