Modeling the thermodynamical conditions in the Uranian subnebula – Implications for regular satellite composition

CNRS-UMR 6091, Observatoire de Besançon, BP 1615, 25010 Besançon Cedex, France

Corresponding author: Olivier.Mousis@obs-besancon.fr

Received: 9 January 2003
Accepted: 12 September 2003

Abstract

We study the thermodynamical conditions existing in the Uranian subnebula from which the regular satellites were presumably formed, assuming it was produced by an earth-sized body impact on proto-Uranus (Stevenson [CITE]; Slattery et al. [CITE]). Two evolutionary turbulent models of the Uranian subnebula are constructed. Both are derived from the solar nebula analytical model of Dubrulle ([CITE]) and Drouart et al. ([CITE]). Each model provides a distinct chemical composition which depends on the assumed origin of the subdisk's material (proto-Uranus or impactor ejected material). Moreover, the evolution of the chemistry of C and N compounds is examined in order to assess the nature of major volatiles trapped into the ices of regular satellites. The temporal evolution of the D/H ratio in water is also explored in the Uranian subdisk, as a function of the gas phase composition. Such an analysis may provide constraints on the origin of the material which led to the formation of the regular satellite system.