Thermal structure of putative hydrocarbon lakes on Titan

Recent radar observations indicate that a large fraction of Titan's surface may be covered by liquid hydrocarbon lakes. Such lakes may play an important role in Titan's chemical evolution in that they would protect organic material from photochemical destruction and may enable the production of new organic species therein. Despite the lack of liquid water it appears meaningful to study the thermal structure of such putative lakes in the context of astrobiology, particularly in comparison with H_2O lakes on Earth. The lake temperature and its spatial and seasonal variation are important in that they control the solubility of chemical species and the liquid density which in turn affects the lake temperature via lake overturning. Depending on the variable lake density solid organics in the lake would either float or sink. In this study the lake temperature and density as well as the solubility of organic species are predicted by a coupled 3-dimensional lake-atmosphere model for different possible chemical compositions.