From mean-motion resonances to scattered planets: Producing the Solar System, eccentric exoplanets and Late Heavy Bombardments

TL;DR

This paper explores how interactions with gas and planetesimal disks shape planetary system evolution, leading to configurations similar to the Solar System or eccentric exoplanets, and possibly causing the Late Heavy Bombardment.

Contribution

It demonstrates a unified mechanism involving gas and planetesimal disk interactions that can produce diverse planetary architectures and dynamical instabilities.

Findings

Gas disk interactions produce closely-spaced, resonant planetary systems.

Remnant planetesimal disks can destabilize resonant configurations over time.

The mechanism explains both Solar System features and eccentric exoplanets.

Abstract

We show that interaction with a gas disk may produce young planetary systems with closely-spaced orbits, stabilized by mean-motion resonances between neighbors. On longer timescales, after the gas is gone, interaction with a remnant planetesimal disk tends to pull these configurations apart, eventually inducing dynamical instability. We show that this can lead to a variety of outcomes; some cases resemble the Solar System, while others end up with high-eccentricity orbits reminiscent of the observed exoplanets. A similar mechanism has been previously suggested as the cause of the lunar Late Heavy Bombardment. Thus, it may be that a large-scale dynamical instability, with more or less cataclysmic results, is an evolutionary step common to many planetary systems, including our own.