2005ApJ...619.1098M -
Astrophys. J., 619, 1098-1113 (2005/February-1)
The thermal regulation of gravitational instabilities in protoplanetary disks. II. Extended simulations with varied cooling rates.
MEJIA A.C., DURISEN R.H., PICKETT M.K. and CAI K.
Abstract (from CDS):
In order to investigate mass transport and planet formation through gravitational instabilities (GIs), we have extended our three-dimensional hydrodynamic simulations of protoplanetary disks from a previous paper. Our goal is to determine the asymptotic behavior of GIs and how it is affected by different constant cooling times. Initially, Rdisk=40 AU, Mdisk=0.07 M☉, M*=0.5 M☉, and Qmin=1.5. Sustained cooling, with tcool=2 ORPs (outer rotation periods; 1ORP~250 yr), drives the disk to instability in about 4 ORPs. This calculation is followed for 23.5 ORPs. After 12 ORPs, the disk settles into a quasi-steady state with sustained nonlinear instabilities, an average Q=1.44 over the outer disk, a well-defined power law Σ(r), and a roughly steady M{dot}~5x10–7 M☉yr–1. The transport is driven by global low-order spiral modes. We restart the calculation at 11.2 ORPs with tcool=1 and (1)/(4) ORPs. The latter case is also run at high azimuthal resolution. We find that shorter cooling times lead to increased M{dot}-values, denser and thinner spiral structures, and more violent dynamic behavior. The asymptotic total internal energy and the azimuthally averaged Q(r) are insensitive to tcool. Fragmentation occurs only in the high-resolution tcool=(1)/(4) ORP case; however, none of the fragments survive for even a quarter of an orbit. Ringlike density enhancements appear and grow near the boundary between GI-active and GI-inactive regions. We discuss the possible implications of these rings for gas giant planet formation.
Abstract Copyright:
∼
Journal keyword(s):
Accretion, Accretion Disks - Hydrodynamics - Stars: Planetary Systems: Formation - Stars: Planetary Systems: Protoplanetary Disks
Simbad objects:
1
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2005ApJ...619.1098M and select 'bookmark this link' or equivalent in the popup menu