Stirring and dynamical friction rates of planetesimals in the solar gravitational field

摘要: Abstract The random velocity (eccentricity and inclination) change of planetesimals due to mutual gravitational scattering is investigated, taking into account the solar field. Viscous stirring dynamical friction rates are presented with three-body formalism (using eccentricity inclination), calculated through a large number ∼10 7−8 ) orbital integrations. results summarized as follows: (1) role distant encounters not important. (2) In low energy cases where Keplerian shear dominates, grows much more rapidly than inclination, effective. viscous time scale for greater two-body relaxation time. (3) high motion 2:1 ratio inclination spontaneously attained. Both scales almost given by time, effective larger planetesimals, which should lead “runaway growth” protoplanets.