The Throat of Kraken : Tidal Dissipation and Mixing Timescales in Titan’s Largest Sea

Introduction: Of Titan’s three seas, Kraken has the largest area, and sprawls over the widest range of latitude and longitude. This extent means it sees the largest variations in tidal accelerations due to Saturn’s gravity, and thus has the largest tides. New Cassini observations map the seas (figure 1) and allow quantification of tidal processes : a feature of particular interest is a narrow ‘throat’ (figure 2) between the two main basins of Kraken. These basins are large enough to serve, like Ligeia Mare, as splashdown sites for future missions like the proposed Titan Mare Explorer (TiME). This throat may see strong tidal currents and significant energy dissipation, as well as acting to restrict mixing of the sea composition. Tidal dissipation in oceans was a central topic in preCassini Titan science [1,2], since such dissipation would be expected to circularize Titan’s eccentric orbit unless the oceans were deep, or confined to small basins [3,4]. Although dissipation in Titan’s interior [5] also presents the same issue, it is interesting to reexamine the question of dissipation in the sea. .