Study of the migration of Earth-like planets in planetesimal disks and the formation of debris disks

Abstract

The aim of this study is to investigate the interaction of Earth-mass planets with a planetesimal disk. It is shown that an Earth-mass planet, initially located near the inner boundary of the planetesimal disk, migrates into the disk. The depth of penetration of the planet into the disk is a random quantity determined by the angular momentum distribution of planetesimals approaching the planet. However, at a certain stage, the direction of the planet's migration changes, and the planet returns to the inner boundary of the disk. During such reversible migration, the planet perturbs the orbits of planetesimals and increases their relative velocities in the region of the disk traversed during its migration. The relative velocities of planetesimals increase to values sufficient for their fragmentation in collisions. Our estimates show that, after the passage of an Earth-mass planet through the outer planetesimal disk, the mean relative velocities in the main part of the disk increase to values sufficient to disrupt monolithic basaltic planetesimals with sizes of 40 km. Thus, the interaction of even a relatively low-mass planet (of order an Earth mass) with a planetesimal disk can lead to the formation of dust particles observed in outer debris disks.