Planetary accretions in jet streams

The problem of planetary accretion in a jet stream is studied using the model developed by Alfvén and Arrhenius. We find that there are basically three types of planetary accretion: namely, fast process τ_c < τ_i, slow process τ_c ~ τ_i and delayed process τ_c > τ_i where τ_c is the characteristic time of the occurrence of catastrophic accretion and τ_i the time-scale of mass injection to the planetary system (≃3×10⁸ yr). 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.