Planetary accretions in jet streams

The problem of planetary accretion in a jet stream is studied using the model developed by Alfven and Arrhenius. We find that there are basically three types of planetary accretion, corresponding to cases where the characteristic time of the occurrence of catastrophic accretion is less than, equal to, or greater than the time-scale of mass injection to the planetary system (300 m.y.). These different time scales of accretion are found to be closely related to the primordial thermal profiles and equatorial inclinations of the planets. Finally, Venus' retrograde rotational spin is shown to be a possible result of accretion process in a jet stream.