Fractionation of the precursor material of the Galilean moons of Jupiter in a dense cooling disk

We analyzed cosmochemical consequences of two alternative models for the structure of the viscous accretion protosatellite disk of Jupiter which were developed by us previously. Model I implies a moderately warm (maximum temperature no higher than 400 K), low-mass (in any time moment, the mass of the disk is no higher than similar to10(25) g), and relatively viscous disk (alpha = 10(-3)), in which radial temperature variations are consistent with the observed distribution of water in the Jovian moons. Model 2 implies a hotter (T greater than or equal to 1500 K in the zone of formation of Io, Europa, and Ganymede) and three to four orders of magnitude less viscous disc, whose mass is determined in accordance with the total mass of the Galilean moons (approximate to6 x 10(28) g). Comparative analysis demonstrated that variant 2 more adequately describes the process of satellite formation, and it is therefore considered as a basic model. The radial distribution of P-T conditions in the disk was calculated for sequential stages of cooling assuming that the disk occurred in a quasi-steady state. It was shown that, within the proposed thermal model, the conditions within the protosatellite disk of Jupiter at the radial distances of Io and Europa were favorable over similar to1 m.y. for the formation of bodies depleted in metal and other refractory elements (Al, Ca, W, Mo, U, REE, etc.) but having the solar Mg/Si ratio.