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

TL;DR

This study uses $N$-body simulations to explore planetary formation in radially structured protoplanetary disks, revealing efficient growth at discontinuities and the potential for solar system-like configurations.

Contribution

It demonstrates that planetary formation can be efficient at radial discontinuities in structured disks, a scenario not extensively studied before.

Findings

Protoplanets reach Earth mass within ~10^4 years at the discontinuity boundary.

Giant collisions of protoplanets occur universally in the model.

Multiple planet-sized bodies form regularly near the boundary.

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 ($\sim0.6$ AU). We found that protoplanets grow efficiently at the discontinuity boundary, reaching the Earth mass within $\sim10^4$ years. We confirmed that giant collisions of protoplanets occur universally in our model. Moreover, we found 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.