On the chemical composition of Titan's dry lakebed evaporites

TL;DR

This study models the chemical composition of Titan's dry lakebed evaporites, suggesting significant amounts of butane and acetylene, but emphasizes the need for laboratory validation due to theoretical uncertainties.

Contribution

It introduces a model combining organic solids dissolution and evaporation to predict evaporite composition on Titan, highlighting potential dominant compounds.

Findings

Large abundances of butane and acetylene are possible in evaporites.

Model results are uncertain and require laboratory confirmation.

Surface composition differs from surrounding terrains, indicating organic deposits.

Abstract

Titan, the main satellite of Saturn, has an active cycle of methane in its troposphere. Among other evidence for a mechanism of evaporation at work on the ground, dry lakebeds have been discovered. Recent Cassini infrared observations of these empty lakes have revealed a surface composition poor in water ice compared to that of the surrounding terrains --- suggesting the existence of organic evaporites deposits. The chemical composition of these possible evaporites is unknown. In this paper, we study evaporite composition using a model that treats both organic solids dissolution and solvent evaporation. Our results suggest the possibility of large abundances of butane and acetylene in the lake evaporites. However, due to uncertainties of the employed theory, these determinations have to be confirmed by laboratory experiments.