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Communication Dans Un Congrès Année : 2016

Titan's mid-latitude surface regions with Cassini VIMS and SAR

Résumé

We investigate the surface of Saturn's moon Titan by means of two Cassini instruments used in synergy. We apply a radiative transfer code to VIMS hyperspectral data to correct the strong atmospheric contribution and extract information on surface composition (Hirtzig et al. 2014; Solomonidou et al. 2014; 2015). We then put this in the context of terrain morphology by use of denoised Synthetic Aperture Radar (SAR) images (Bratsolis et al. 2012). We examine here the mid-latitude zones extending from 50ºN to 50ºS, which includes key geological features identified in Lopes et al. (2010, 2015) and Malaska et al. (2015): mountains, plains, labyrinths, dune fields, and possible cryovolcanic and/or evaporitic deposits. We find that many of the different units show compositional variations while units of significant geomorphological differences seem to consist of very similar material mixtures. The Huygens landing site and the candidate evaporitic regions are compositionally similar to the variable plains. We also find that temporal variations of surface albedo exist for two of the candidate cryovolcanic regions Tui Regio and Sotra Patera, suggesting the presence of surface activity, while a number of other regions such as Hotei Regio and the undifferentiated plains remain unchanged (Solomonidou et al. 2015). The surface albedo variations, together with the presence of volcanic-like morphological features, suggest that the active regions are possibly related to the deep interior, possibly via cryovolcanic processes (with important implications for the satellite's astrobiological potential) as also indicated by recent interior structure models of Titan and corresponding calculations of the spatial pattern of maximum tidal stresses (Sohl et al. 2014). In previous studies (Lopes et al. 2015; Solomonidou et al. 2015) we showed that a variety of surface processes could be linked to the formation of the various geomorphological units (aeolian, fluvial, sedimentary, lacustrine) as well as the deposition of atmospheric products through the process of photolysis and sedimentation of organics. The surface albedo differences and similarities among the various geomorphological terrains constrain the implications for the geological processes that govern Titan's surface. [1] Bratsolis, E., et al.: PSS, 61, 108-113, 2012; [2] Hirtzig, M., et al.: Icarus, 226, 470-486, 2013; [3] Solomonidou, A., et al.: JGR, 119, 1729-1747, 2014; [4] Lopes, R.M.C., et al.: Icarus, 205, 540-558, 2010; [5] Lopes, R.M.C., et al.: Icarus, in press, 2015; [6] Malaska, M., et al.: Icarus, in press, 2015; [7] Solomonidou, A., et al.: Icarus, in press, 2015; [8] Sohl, F., et al.: JGR, 119, 1013-1036, 2014.
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Dates et versions

hal-03734160 , version 1 (21-07-2022)

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Anezina Solomonidou, Athéna Coustenis, Pierre Drossart, Robert H. Brown, Frank Sohl, et al.. Titan's mid-latitude surface regions with Cassini VIMS and SAR. 41st COSPAR Scientific Assembly, Jul 2016, Istanbul, Turkey. ⟨hal-03734160⟩
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