Planet Migration

TL;DR

This paper reviews the mechanisms and models of planet migration, focusing on gravitational interactions with gaseous disks, discussing uncertainties and alternative migration processes affecting planet formation.

Contribution

It introduces a simple model for disk-driven migration rates and discusses uncertainties and alternative migration mechanisms in planet formation.

Findings

Migration rates from the simple model are higher than sustainable for planet survival.

Uncertainties in migration rates stem from limited knowledge of disk physical properties.

Alternative migration mechanisms are also described.

Abstract

Planet migration is the process by which a planet's orbital radius changes in time. The main agent for causing gas giant planet migration is the gravitational interaction of the young planet with the gaseous disk from which it forms. We describe the migration rates resulting from these interactions based on a simple model for disk properties. These migration rates are higher than is reasonable for planet survival. We discuss some proposed models for which the migration rates are lower. There are major uncertainties in migration rates due to a lack of knowledge about the detailed physical properties of disks. We also describe some additional forms of migration.