Dead zones and the diversity of exoplanetary systems
Abstract
Planetary migration provides a theoretical basis for the observed diversity of exoplanetary systems. We demonstrate that dust settling - an inescapable feature of disk evolution - gives even more rapid type I migration by up to a factor of about 2 than occurs in disks with fully mixed dust. On the other hand, type II migration becomes slower by a factor of 2 due to dust settling. This even more problematic type I migration can be resolved by the presence of a dead zone; the inner, high density region of a disk which features a low level of turbulence. We show that enhanced dust settling in the dead zone leaves a dusty wall at its outer edge. Back-heating of the dead zone by this wall produces a positive radial gradient for the disk temperature, which acts as a barrier for type I migration.
- Publication:
-
The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution
- Pub Date:
- November 2011
- DOI:
- 10.1017/S1743921311020667
- arXiv:
- arXiv:1111.5238
- Bibcode:
- 2011IAUS..276..430H
- Keywords:
-
- accretion;
- accretion disks;
- radiative transfer;
- turbulence;
- planetary systems: protoplanetary disks;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 2 pages, 1 figure, published in Proceedings IAU Symposium No. 276