Cassini/VIMS Data Analysis of Potentially Geologically Varying Regions on Titan

Kurzfassung

Abstract We present a study of Titan's geology with a view to enhance our current understanding of some particular regions on the satellite's surface, which may be varying in brightness and/or in color etc. We apply here a statistical method, the Principal Component Analysis (PCA) [1] and a radiative transfer code (RT) [1,2] on three such potentially "active" regions: Tui Regio, Hotei Regio, and Sotra Facula, within which we isolate specific regions of distinct and diverse chemical composition with PCA. Then, with our follow-up RT method, we retrieve the surface albedo of these specific isolated regions and of the surrounding terrains exhibiting different spectral responses. We thus evaluate the atmospheric contribution and can constrain the real surface alterations, by comparing the spectra of these regions. We search for the temporal surface variations of Hotei Regio (as reported by Nelson et al. 2009 [3]), with our RT code and the same data from 2004-2006, and do not find any significant surface albedo variations over time. We then superimposed this area's Cassini Visual and Infrared Mapping Spectrometer (VIMS) and RADAR data in order to 'view' the morphological potential. We find that even if these regions have not visually changed over the course of the Cassini mission, the determination of the chemical composition and the correlation with the morphological structures [4] observed in these areas do not rule out past and/or ongoing cryovolcanic processes as a possible interpretation. [1] Solomonidou, A., et al.: In preparation. [2] Hirtzig, M. et al.: In preparation. [3] Nelson, R. et al.: Icarus 199, 429-441, 2009. [4] Solomonidou, A et al.: PSS, accepted, 2012.