Giant planet migration, disk evolution, and the origin of transitional disks

TL;DR

This paper models giant planet migration within evolving protoplanetary disks, demonstrating that simple models can explain observed exoplanet distributions and disk lifetimes, while revealing a coupling between planet formation and disk clearing.

Contribution

It introduces a coupled model of planet migration and disk evolution, including photoevaporation, to explain the origin of transitional disks and their observable properties.

Findings

Models reproduce observed exoplanet radial distributions.

State-of-the-art photoevaporation links planet formation and disk clearing.

Different types of transitional disks have distinct observable signatures.

Abstract

We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce both the observed radial distribution of extra-solar giant planets, and the lifetimes and accretion histories of protoplanetary disks. The use of state-of-the-art photoevaporation models results in a degree of coupling between planet formation and disk clearing, which has not been found previously. Some accretion across planetary orbits is necessary if planets are to survive at radii <~1.5AU, and if planets of Jupiter mass or greater are to survive in our models they must be able to form at late times, when the disk surface density in the formation region is low. Our model forms two different types of "transitional" disks, embedded planets and clearing disks, which show markedly different properties. We find that the observable properties of these systems are broadly consistent with current observations, and highlight useful observational diagnostics. We predict that young transition disks are more likely to contain embedded giant planets, while older transition disks are more likely to be undergoing disk clearing.