Numerical modeling of endogenic thermal anomalies on Europa

A variety of recent resurfacing features have been observed on Europa, which may produce thermal anomalies detectable by a future mission. However, the likelihood of such a detection depends on their size and lifetimes. The results of this numerical study suggest that the lifetime of a thermal anomaly associated with the emplacement of 100 m of water onto the surface of Europa is several hundred years, and similar to 10 years for 10 m of water. If warm ice is emplaced on the surface instead of liquid water, these lifetimes decrease by up to a factor of two. Exploration of model parameters indicates that a thin insulating surface layer can double thermal anomaly lifetimes, anomalies emplaced at a latitude of 80 degrees can remain detectable nearly a factor of two longer than those at equatorial latitudes, and anomalies on the night side can remain detectable for up to similar to 20% longer than those on the day side. High temperatures are very short-lived as the surface ice cools very rapidly to below 200 K due to sublimation cooling. Assuming steady-state resurfacing, the number of detectable thermal anomalies associated with the emplacement of 100 m of water would be on the order of 10 if the typical resurfacing area is 15 km(2). If recent resurfacing is dominated by chaos regions with typical areas of 100 to 1000 km(2) and lifetimes of 1000 to 4000 years, the number of detectable thermal anomalies would be on the order of 1 to 10. (C) 2007 Elsevier Inc. All rights reserved.