Abstract
We simulate the final formation of terrestrial planets during the epoch of protoplanetary disk depletion. Previous studies show that the isolated protoplanets grow up to their final sizes through dynamical instability among the protoplanets. However, the formed terrestrial planet systems generally have relatively high eccentricities. Although mechanisms which damp the eccentricity have been proposed, these mechanisms tend to inhibit the planetary growth. We consider that the eccentricities are excited through a sweeping secular resonance rather than dynamical instability. We find that the secular resonance passes through the terrestrial region from outside to inside and that the resonance excites the eccentricities of isolated protoplanets during disk depletion. The tidal drag causes the semi-major axes and eccentricities to decay. The migration of protoplanets along with the secular resonance induces isolated protoplanets to grow through collisions. We conclude that the Jovian sweeping secular resonance combined with tidal drag allows the system to form circular orbits analogous to our Solar System.
