Distribution and intensity of water ice signature in South Xanadu and Tui Regio

Maélie Coutelier (1) , Daniel Cordier (1) , Benoît Seignovert (2, 3) , Pascal Rannou (1) , Alice Le Gall (4, 5) , Thibaud Cours (1) , Luca Maltagliati (6) , Sébastien Rodriguez (7)

1 GSMA - Groupe de spectrométrie moléculaire et atmosphérique
2 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]
3 JPL - Jet Propulsion Laboratory
4 PLANETO - LATMOS
5 IUF - Institut universitaire de France
6 Nature Publishing Group
7 IPGP (UMR_7154) - Institut de Physique du Globe de Paris

Titan's surface was revealed by Cassini's instruments, showing the presence of liquid hydrocarbons in lakes, and features like dry riverbed. In order to study the sediment transport in Titan's channels and to map distribution of the water-ice signature in these terrains, we use a radiative transfer model to retrieve the surface albedo, after we estimated VIMS error with an original method. We also establish a criteria related to the intensity of the water ice signature. The tuning of the radiative transfer model shows that the fractal dimension of Titan's aerosols is higher than previously thought, around 2.3–2.4. We find spots of high signal of water ice downstream, at the margins of Tui Regio, that could correspond to alluvial fans, deltas or crater rims. We also observe a very low water ice signal on Tui Regio, with a positive gradient between the central region and the boundary of the area, possibly due to the thickness variation of an evaporitic layer. The riverbeds show within the error bars a decreasing grain size from the top to the bottom of the channels. This reinforces the hypothesis of sediment transport via these river channels.

Mots clés: Titan; Radiative transfer; River channels; Water ice; VIMS

Domaines: Planète et Univers [physics]

Maélie Coutelier, Daniel Cordier, Benoît Seignovert, Pascal Rannou, Alice Le Gall, et al.. Distribution and intensity of water ice signature in South Xanadu and Tui Regio. Icarus, 2021, 364 (August), pp.114464. ⟨10.1016/j.icarus.2021.114464⟩. ⟨insu-03194788⟩