Titan’s mid-latitude surface region from Cassini/VIMS data: Implications on the composition

Anezina Solomonidou (1) , Athéna Coustenis (2) , Rosaly M. C. Lopes (1) , Michael Malaska (1) , Sébastien Rodriguez (3) , Pierre Drossart (2) , Charles Elachi (1) , Bernard Schmitt (4) , Sylvain Philippe (4) , Michael A. Janssen (1) , Mathieu Hirtzig (2) , Stephen D. Wall (1) , Kenneth J. Lawrence (1) , Nicolas Altobelli (5) , Emmanuel Bratsolis (6) , Jani Radebaugh (7) , Katrin Stephan (8) , Robert H. Brown (9) , Stéphane Le Mouélic (10) , Alice Le Gall (11) , Edward Villanueva (1) , Anthony Bloom (1) , Olivier Witasse (12) , Christos Matsoukas (13) , Ashley Schoenfeld (14)

1 JPL - Jet Propulsion Laboratory
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
4 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
5 ESAC - European Space Astronomy Centre
6 Department of Physics [Athens]
7 Department of Geological Sciences [BYU]
8 DLR Institute of Planetary Research
9 LPL - Lunar and Planetary Laboratory [Tucson]
10 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]
11 PLANETO - LATMOS
12 ESTEC - European Space Research and Technology Centre
13 KTH - Royal Institute of Technology [Stockholm]
14 EPSS - Department of Earth, Planetary and Space Sciences [Los Angeles]

We investigate the surface of Titan using spectro-imaging near-infrared data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). We apply a radiative transfer code to first determine the contributions of atmospheric haze to the Titan spectrum and then derive the surface albedo (Solomonidou et al. 2014; 2016). We focus here on the geological major units identified in Lopes et al. (2010, 2016), Malaska et al. (2016) and Radebaugh et al. (2016) from Synthetic Aperture Radar (SAR), data including mountains, different types of plains, labyrinths, impact craters, dune fields, and alluvial fans. We find that all regions classified as being the same geomorphological unit in SAR exhibit a coherent spectral response after the VIMS data analysis, thus suggesting a good correlation in the classification between SAR and VIMS. The Huygens landing site appears to be compositionally similar to one type of plains unit (variable plains), suggesting similar plain formation mechanisms. We have sub-categorized the VIMS data into three albedo categories (high, medium, low). By matching the extracted albedos with candidate materials for Titan’s surface (GhoSST database), we find that all regions of interest fall into one out of three main types of major candidate constituents: water ice, tholin-like material, or an unknown, very dark material. This suggests that Titan’s surface is possibly dominated by tholin-like material and a very dark unknown (most likely organic) material, and that most of the surface is covered by atmospheric/organic deposits. Water ice is also present at a number of regions as major constituent at latitudes higher than 30N and 30S. The surface albedo differences and similarities among the various geomorphological units constrain the implications for the geological processes that govern Titan’s surface and interior (e.g. aeolian, fluvial, sedimentary, lacustrine, cryovolcanic, tectonic).References: Lopes et al.: Icarus, 205, 540-558, 2010; Lopes et al.: Icarus, 270, 162-182, 2016; Malaska et al.: Icarus, 270, 130-161, 2016; [4] Solomonidou et al.: JGR, 119, 1729-1747, 2014; [6] Solomonidou et al.: Icarus, 270, 85-99, 2016; [7] Schmitt et al.: GhoSST database (ghosst.osug.fr).

Domains: Sciences of the Universe [physics]

Anezina Solomonidou, Athéna Coustenis, Rosaly M. C. Lopes, Michael Malaska, Sébastien Rodriguez, et al.. Titan’s mid-latitude surface region from Cassini/VIMS data: Implications on the composition. 49th Annual Division for Planetary Sciences Meeting, Oct 2017, Provo, United States. ⟨insu-01664449⟩