Numerical simulations of type III planetary migration: III. Outward migration of massive planets

TL;DR

This study uses 2D hydrodynamical simulations to analyze outward type III migration of Jupiter-sized planets, revealing dependencies on initial conditions, co-orbital region structure, and mass accumulation rates.

Contribution

It provides detailed insights into the physics, structure, and stopping mechanisms of outward type III planetary migration, highlighting the influence of initial conditions and circumplanetary mass growth.

Findings

Outward migration can be initiated if initial conditions support Z > 1.

Migration rate increases with the growth of the co-orbital volume.

Two regimes of migration, fast and slow, depend on circumplanetary mass accumulation.

Abstract

We present a numerical study of rapid, so called type III migration for Jupiter-sized planets embedded in a protoplanetary disc. We limit ourselves to the case of outward migration, and study in detail its evolution and physics, concentrating on the structure of the co-rotation and circumplanetary regions, and processes for stopping migration. We also consider the dependence of the migration behaviour on several key parameters. We perform this study using global, two-dimensional hydrodynamical simulations with adaptive mesh refinement. We find that the outward directed type III migration can be started if the initial conditions support $Z > 1$, that corresponds to initial value $M_\rmn{\Delta} \ga 1.5$. Unlike the inward directed migration, in the outward migration the migration rate increases due to the growing of the volume of the co-orbital region. We find the migration to be strongly dependent on the rate of the mass accumulation in the circumplanetary disc, leading to two possible regimes of migration, fast and slow. The structure of the co-orbital region and the stopping mechanism differ between these two regimes.