Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations

This is an author-produced, peer-reviewed version of this article. The final, definitive version of this document can be found online at Icarus, published by Elsevier. Copyright restrictions may apply. doi: 10.1016/j.icarus.2008.12.028 – 2 – We analyze observations of Titan’s south polar lake Ontario Lacus obtained by Cassini ’s Visual and Infrared Mapping Spectrometer during the 38th flyby of Titan (T38; 2007 December 5). The near-closest-approach observations have the highest signal-to-noise, the finest spatial resolution, and the least atmospheric influence of any near-infrared lake observation to date. We use the large, spatially flat, and low-albedo interior of Ontario Lacus as a calibration target allowing us to derive an analytical atmospheric correction for emission angle. The dark lake interior is surrounded by two separate annuli that follow the lake interior’s contours. The inner annulus is uniformly dark, but not so much as the interior lake, and is generally 5-10 kilometers wide at the lake’s southeastern margin. We propose that it represents wet lakebed sediments exposed by either tidal sloshing of the lake or seasonal methane loss leading to lowe