Deep and methane-rich lakes on Titan
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Saturn’s largest moon, Titan, hosts liquid hydrocarbon lakes and seas on its surface. During the last close encounter with Titan (22 April 2017), the Cassini spacecraft used its RADAR as a sounder to probe the depth of several lakes in the north polar terrain. This was the first time that Titan’s lakes, as opposed to its seas, have been viewed in a sounding configuration. Here, we show that these lakes can exceed 100 m depth and their transparency at the 2.17 cm radar wavelength indicates that they have a methane-dominated composition. This composition differs significantly from that of Ontario Lacus, the only major lake in Titan’s southern hemisphere, which is more ethane rich. If the methane-rich north polar lakes, perched hundreds of metres above the major seas, are formed by a karstic-type process, then they may drain by subsurface flow at rates between 0.001 and 1 m yr−1 (Titan year). Subsurface reservoirs and flows therefore may be an important element of the Titan geochemical system.
Astronomy And Planetary Science, Geochemistry, Geomorphology, Planetary Science
Nature Astronomy, Vol. 3 (2019).
Mastrogiuseppe, M.; Poggiali, V.; Hayes, A. G.; Lunine, J. I.; Seu, R.; Mitri, G.; and Lorenz, R. D., "Deep and methane-rich lakes on Titan" (2019). KIP Articles. 1423.