Summary: Icarus 195 (2008) 378385
Numerical modeling of endogenic thermal anomalies on Europa
, John R. Spencer
Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA
Received 2 April 2007; revised 11 November 2007
Available online 8 January 2008
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 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 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 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 km2. If recent resurfacing is dominated by chaos regions with typical
areas of 100 to 1000 km2 and lifetimes of 1000 to 4000 years, the number of detectable thermal anomalies would be on the order of 1 to 10.
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