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

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{Stevenson84}; Slattery et al. \cite{Slattery92}). Two evolutionary turbulent models of the Uranian subnebula are constructed. Both are derived from the solar nebula analytical model of Dubrulle (\cite{Dubrulle93}) and Drouart et al. (\cite{Drouart99}). 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.