FORMATION OF SATELLITE SYSTEMS - PROGRADE AND RETROGRADE SATELLITES OF JUPITER AND SATURN

Prograde and retrograde trajectories of particles in a protosatellite disk are investigated numerically within the scope of the plane circul ar three-body problem. It is shown that solar perturbations inhibit ac cretion in a prograde disk at radii greater than r = 19.5 x 10(6) km f or Jupiter and 25 X 10(6) km for Saturn. The change in surface density of prograde disks of Jupiter and Saturn with accumulation of planetes imals from heliocentric orbits is investigated numerically. It is show n that regions of particles with retrograde motion develop in an initi ally prograde disk. The radii of these regions agree well with the ret rograde satellites-Phoebe and the Pasiphae group. The accumulation zon es for prograde particles also agree well with the main groups of prog rade satellites of Jupiter and Saturn, including the Himalia group. Th ese results refute the capture hypothesis for the outer satellites of Jupiter and Saturn.