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D. Gautier (Obs. Paris), F. Hersant (Obs. Paris and CEA Saclay), O. Mousis (Obs. Paris and University of Nantes)
An enrichment by a factor 2 to 4 with respect to the solar abundance has been measured in C, N, S, Ar, Kr and Xe abundance by the mass spectrometer aboard the Galileo probe (Atreya et al., 1999, PSS, 47, 1243, Owen et al., 1999, Nature, 402, 269). Using a 2-D evolutionary model of the solar nebula (Hersant et al., 2000, DPS meeting), we can calculate at what time and temperatures volatiles are trapped in the form of clathrate hydrates in the feeding zone of Jupiter. In gaseous form, the abundances of various volatiles decrease with hydrogen in the feeding zone, but clathrate hydrates agglomerate, grow up rapidly and are decoupled from the gas, so that their mixing ratio with respect to hydrogen increases with time. Hydrogen collapses onto the core of Jupiter as a result of hydrodynamic instability, at the time when the mass of gas in the feeding zone is of the order of the current value of H2 in Jupiter. This scenario permits us to quantitatively reproduce the mentionned above enrichments in heavy elements.