The role of ocean circulation in driving hemispheric symmetry breaking of the ice shell of Enceladus

TL;DR

This study investigates how ocean circulation influences the hemispheric asymmetry of Enceladus's ice shell, revealing that heat transport and feedback mechanisms can lead to multiple equilibrium states and explain observed asymmetries.

Contribution

The paper introduces a novel analysis of ocean circulation's impact on ice shell asymmetry, highlighting the role of heat transport and feedback in hemispheric differences.

Findings

Ocean heat transport affects ice shell asymmetry.

Multiple equilibrium states can exist due to feedback.

Ocean circulation significantly influences ice shell evolution.

Abstract

The ice shell of Enceladus exhibits strong asymmetry between its hemispheres, with all known geysers concentrated over the south pole, even though its orbital configuration is almost perfectly symmetric. By exploring ocean circulation across a range of ocean salinities and core/shell heating partitions, we study the role of ice-ocean interaction in hemispheric symmetry breaking. We find that: (i) asymmetry is enhanced by cross-equatorial ocean heat transport when the ice shell is the major heat source and vice versa, (ii) the magnitude of ocean heat transport is comparable to the global heat production, significantly affecting the ice shell evolution and equilibrium state and (iii) more than one equilibrium state can exist due to a positive feedback between melting and ocean circulation.