N-body simulation of planetary formation through pebble accretion in a radially structured protoplanetary disk

Abstract

Abstract In the conventional theory of planet formation, it is assumed that protoplanetary disks are axisymmetric and have a smooth radial profile. However, recent radio observations of protoplanetary disks have revealed that many of them have complex radial structures. In this study, we perform a series of N-body simulations to investigate how planets are formed in protoplanetary disks with radial structures. For this purpose, we consider the effect of continuous pebble accretion onto the discontinuity boundary within the terrestrial planet-forming region (∼0.6 au). We find that protoplanets grow efficiently at the discontinuity boundary, reaching the Earth mass within ∼104 yr. We confirm that giant collisions of protoplanets occur universally in our model. Moreover, we find that multiple planet-sized bodies form at regular intervals in the vicinity of the discontinuity boundary. These results indicate the possibility of the formation of solar system-like planetary systems in radially structured protoplanetary disks.