ENCELADUS’ SOUTH POLAR TERRAIN: HEAT PIPE CONTROL OF REGIONAL HEATING AND ERUPTIONS

The spectacular plumes emanating from the Enceladus’ South Polar Terrain (SPT) are dominated by water vapor and ice grains. However, they also include molecular hydrogen, indicating the probable interaction of the water source hydrothermally reacting with rocks, and the origination of the source below the icy crust at the water-rock interface. This points toward a potential life habitability zone. An understanding of the long term viability of the plume generation heat source and material transport to the surface will be necessary for understanding the probable longevity of the habitable zone.

We investigate the SPT region as an area of heat pipe activity for moving heat and materials in the form of heated salt water. We use Cassini mission data as thermal and geometry constraints in order to model the SPT region as a 2-D section of the water layer and icy crust with time variable flow through the water-filled cracks.. We assume that the water is in thermal equilibrium with the base of the icy crust, and model the rise through narrow cracks from the base of the icy lithosphere to the surface with conductive and convective losses to the walls. We track phase changes, heat flow through the surrounding walls, and and heat flux at the surface. As in all heat pipe regions, repeated passage of material yields localized thermal and structural weakness zones favoring continued long-duration eruptions from these zones, leaving more distant crustal areas relatively cold and thick. Models of the SPT area as a long term heat pipe region are consistent with the maintenance of a regional—rather than a global—subsurface ocean, although they do not eliminate the possibility of a global subsurface ocean with enhanced regional heat transfer.