Longterm Stability of Planetary Systems formed from a Transitional Disk

TL;DR

This study models the long-term evolution of planetary systems formed in transitional disks, revealing discrepancies in orbital eccentricities and resonance stability compared to observed exoplanets, and suggesting alternative formation pathways.

Contribution

It extends previous simulations by evolving planetary systems for 10 Gyr post-disk dissipation and compares their properties to observed giant planets, highlighting differences in orbital eccentricities and resonance occurrences.

Findings

Simulated systems have more circular orbits than observed.

Few systems become unstable, possibly due to initial stability constraints.

Resonant systems disrupted early, within 10 Myr.

Abstract

Transitional disks are protoplanetary disks with large and deep central holes in the gas, possibly carved by young planets. Dong, R., & Dawson, R. 2016, ApJ, 825, 7 simulated systems with multiple giant planets that were capable of carving and maintaining such gaps during the disk stage. Here we continue their simulations by evolving the systems for 10 Gyr after disk dissipation and compare the resulting system architecture to observed giant planet properties, such as their orbital eccentricities and resonances. We find that the simulated systems contain a disproportionately large number of circular orbits compared to observed giant exoplanets. Large eccentricities are generated in simulated systems that go unstable, but too few of our systems go unstable, likely due to our demand that they remain stable during the gas disk stage to maintain cavities. We also explore whether transitional disk inspired initial conditions can account for the observed younger ages of 2:1 resonant systems orbiting mature host stars. Many simulated planet pairs lock into a 2:1 resonance during the gas disk stage, but those that are disrupted tend to be disrupted early, within the first 10 Myr. Our results suggest that systems of giant planets capable of carving and maintaining transitional disks are not the direct predecessors of observed giant planets, either because the transitional disk cavities have a different origin or another process is involved, such as convergent migration that pack planets close together at the end of the transitional disk stage.