High heat flow from Enceladus' south polar region measured using 10-600 cm^-1 Cassini/CIRS data

Abstract

Analysis of 2008 Cassini Composite Infrared Spectrometer (CIRS) 10 to 600 cm^-1 thermal emission spectra of Encleadus shows that for reasonable assumptions about the spatial distribution of the emission and the thermophysical properties of the solar-heated background surface, which are supported by CIRS observations of background temperatures at the edge of the active region, the endogenic power of Enceladus' south polar terrain is 15.8 ± 3.1 GW. This is significantly higher than the previous estimate of 5.8 ± 1.9 GW. The new value represents an improvement over the previous one, which was derived from higher wave number data (600 to 1100 cm^-1) and was thus only sensitive to high-temperature emission. The mechanism capable of producing such a high endogenic power remains a mystery and challenges the current models of proposed heat production.