Turtle, E. P., McEwen, A. S., Perry, J., West, R. A., Fussner, S., Dawson, D. D., Porco, C. C. (2006). "Cassini Imaging Observations of Titan's Surface." American Astronomical Society, DPS meeting #38, #52.01.


Abstract
In just over two years since insertion into orbit around Saturn, Cassini's complement of instruments has made observations of Titan during sixteen close passes as well as other more distant opportunities. Using filters in the near infrared chosen to coincide with windows in the absorption spectrum of methane, Cassini's Imaging Science Subsystem has been accumulating coverage of Titan's surface. The scales of features that can be resolved in the developing map range from approximately 1 km, achieved in regions of the sub- and anti-Saturnian hemispheres which have been viewed several times at close range as a result of the spacecraft's trajectory, to a few tens of kilometers in other areas. The albedo patterns revealed on the surface represent a variety of geological features: linear boundaries suggest faulting and tectonic control, bright, east-west aligned, streamlined shapes suggest aeolian processes, narrow, curvilinear, dark lines that wind across the surface appear to be fluvial channels, and Ontario Lacus, a dark feature near the South Pole that is a few hundred kilometers long with a very smooth boundary is reminiscent of a lake, the surprisingly rare circular structures may be impact craters, and more complex patterns still defy easy interpretation. These observations, in combination with those from other instruments are consistent with the hypothesis that dark regions are generally topographic lows in which hydrocarbon material precipitating out of the atmosphere has collected. Thorough analysis of 65 images that include the specular point has not provided any indication of the enhancement that would be expected were substantial bodies of liquid present, thereby agreeing with the interpretation that aeolian processes dominate in equatorial regions. We will present the most recent surface observations (two flybys are planned for September and another is scheduled during the DPS meeting) and interpretations thereof.