Letter to the Editor

Halting type I planet migration in non-isothermal disks

¹ Leiden Observatory, Postbus 9513, 2300 RA Leiden, The Netherlands e-mail: paardeko@strw.leidenuniv.nl
² Stockholm Observatory, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden e-mail: garrelt@astro.su.se

Received: 28 August 2006
Accepted: 20 September 2006

Abstract

Aims.We investigate the effect of including a proper energy balance on the interaction of a low-mass planet with a protoplanetary disk.

Methods.We use a three-dimensional version of the RODEO method to perform hydrodynamical simulations including the energy equation. Radiation is included in the flux-limited diffusion approach.

Results.The sign of the torque is sensitive to the ability of the disk to radiate away the energy generated in the immediate surroundings of the planet. In the case of high opacity, corresponding to the dense inner regions of protoplanetary disks, migration is directed outward, instead of the usual inward migration that was found in locally isothermal disks. For low values of the opacity we recover inward migration and show that torques originating in the coorbital region are responsible for the change in migration direction.