Degree-one convection and the origin of Enceladus’ dichotomy

• Published in: Icarus
• Main Authors: Grott, M., Sohl, F., Hussmann, H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2007
• Subjects: Planetenphysik; South pole
• Online Access: https://elib.dlr.de/51676/

Recently, the Cassini spacecraft has detected ongoing geologic activity near the south pole of Saturn’smoon Enceladus. In contrast, the satellite’s north-polar region is heavily cratered and appears to have been geologically inactive for a long time. We propose that this hemispheric dichotomy is caused by interior dynamics with degree-one convection driving the south-polar activity. We investigate a number of core sizes and internal heating rates for which degree-one convection occurs. The numerical simulations imply that a core radius of less than 100±20 km and an energy input at a rate of 3.0 to 5.5 GW would be required for degree-one convection to prevail. This is within the range of the observed thermal power release near Enceladus’ south pole. Provided that Enceladus is not fully differentiated, degree-one convection is found to be a viable mechanism to explain Enceladus’ hemispheric dichotomy.