Widespread CO2 and other non-ice compounds on the anti-Jovian and trailing sides of Europa from Galileo/NIMS observations

摘要

An observation at wavelengths 0.7 - 5.3 mu m of the anti-Jovian and trailing sides of the moon Europa by the Near Infrared Mapping Spectrometer on the Galileo spacecraft has been reprocessed to reveal new details in the > 3.0 mu m infrared spectrum. The revealed features include strong absorption bands centered at 4.25 and 4.0 mu m, attributed to CO2 and SO2, as well as weaker bands, such as near 3.5 mu m attributed to H2O2. The calculated band depth distribution of both the CO2 and SO2 show that the CO2 is strongly associated with the (possibly endogenic) dark (typically hydrate) regions on the surface, while the SO2 is not strongly correlated with the CO2, but has a similar sparse distribution. The association of CO2 with the hydrates may indicate a CO2-rich ocean that is a potential environment for autotrophic organisms that might thrive near the rock-ocean interface, similar to the earliest life on Earth.