%0 Journal Article
%T Deep and methane-rich lakes on Titan
%J -
%D 2019
%R https://doi.org/10.1038/s41550-019-0714-2
%X 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
%U https://www.nature.com/articles/s41550-019-0714-2