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Y. Alibert, O. Mousis (University of Bern)
We have elaborated an evolutionary turbulent model of the Jovian subnebula consistent with formation models of Jupiter described by Alibert et al. (A& A 2004, 417, L25; SSR 2004, in press). This model takes into account the vertical structure of the subnebula, as well as the evolution of the surface density due to viscosity and is used to calculate the thermodynamical conditions in the subdisk, for different values of the viscosity parameter. We show that the Jovian subnebula evolves in two different phases during its lifetime. In the first phase, the subnebula is fed through its outer edge by the solar nebula as long as it has not been dissipated. In the second phase, the solar nebula has disappeared and the Jovian subdisk expands and gradually clears with time by accreting its material onto the forming Jupiter. We also demonstrate that early generations of satellites formed during the first phase of the subnebula cannot survive in this environment and fall onto the proto-Jupiter. As a result, these bodies are susceptible to contribute to enrich the forming Jupiter in heavy elements. Moreover, migration calculations in the Jovian subnebula allow us to follow the evolution of the ices/rocks ratios in the proto-satellites as a function of their migration pathways. By tempting to reproduce the distance distribution of the Galilean satellites, as well as their ices/rocks ratios, we obtain some constraints on the viscosity parameter of the Jovian subnebula in the framework of the \alpha-disk theory. Thus, the preferred value for the \alpha-parameter is found around 1 to 2.10-4.
This work was supported by the Swiss National Science Foundation and by an ESA external fellowship.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.