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

TL;DR

This study uses radiative transfer modeling to map water ice distribution on Titan's surface, revealing spatial variations and potential geological features like alluvial fans and evaporitic layers.

Contribution

It introduces an original method for estimating VIMS error and refines the aerosol fractal dimension, advancing understanding of Titan's surface composition and sediment transport.

Findings

Increased water ice signal at Tui Regio margins suggests alluvial features.

Low water ice signal in Tui Regio indicates possible evaporitic layer.

Riverbed grain size decreases from top to bottom within channels.

Abstract

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 via 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 increasing 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.