Effects of Dust Growth and Settling in T Tauri Disks
- 10 February 2006
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 638 (1), 314-335
- https://doi.org/10.1086/498861
Abstract
We present self-consistent disk models of T Tauri stars that include a parameterized treatment of dust settling and grain growth, building on techniques developed in a series of papers by D'Alessio et al. The models incorporate depleted distributions of dust in upper disk layers along with larger sized particles near the disk midplane, which are expected theoretically and, as we suggested earlier, are necessary to account for millimeter-wave emission, SEDs, scattered light images, and silicate emission features simultaneously. By comparing the models with recent mid- and near-IR observations, we find that the dust-to-gas mass ratio of small grains at the upper layers should be <10% of the standard value. The grains that have disappeared from the upper layers increase the dust-to-gas mass ratio of the disk interior; if those grains grow to maximum sizes of the order of millimeters during the settling process, then both the millimeter-wave fluxes and spectral slopes can be consistently explained. Depletion and growth of grains can also enhance the ionization of upper layers, increasing the possibility of the magnetorotational instability for driving disk accretion.Keywords
This publication has 54 references indexed in Scilit:
- Observations and Modeling of the Inner Disk Region of T Tauri StarsThe Astrophysical Journal, 2005
- The Effects of UV Continuum and Ly Radiation on the Chemical Equilibrium of T Tauri DisksThe Astrophysical Journal, 2003
- Warm molecular layers in protoplanetary disksAstronomy & Astrophysics, 2002
- Evidence for a Developing Gap in a 10 Myr Old Protoplanetary DiskThe Astrophysical Journal, 2002
- Two-dimensional distributions and column densities of gaseous molecules in protoplanetary disksAstronomy & Astrophysics, 2001
- Spectral Energy Distributions of T Tauri Stars with Passive Circumstellar DisksThe Astrophysical Journal, 1997
- Spectral evolution of stellar populations using isochrone synthesisThe Astrophysical Journal, 1993
- Particle emissivity in circumstellar disksThe Astrophysical Journal, 1991
- Irradiation of accretion disks around young objects. I - Near-infrared CO bandsThe Astrophysical Journal, 1991
- A survey for circumstellar disks around young stellar objectsThe Astronomical Journal, 1990