The T Tauri star RY Tauri as a case study of the inner regions of circumstellar dust disks
Aims:We study the inner region (~1.0 AU up to a few 10 AUs) of the circumstellar disk around the “classical” T Tauri star
Methods: Our analysis is done within the framework of a passively heated circumstellar disk, which is optionally supplemented by the effects of accretion and an added envelope. To achieve a more consistent and realistic model, we used our continuum transfer code MC3D. In addition, we studied the shape of the 10 μ m silicate emission feature in terms of the underlying dust population, both for single-dish and for interferometric measurements.
Results: We show that a modestly flaring disk model with accretion can explain both the observed spectral energy distribution and the mid-infrared visibilities obtained with the mid-infrared infrared instrument. We found an interesting ambiguity: a circumstellar active disk model with an added envelope, and a lower accretion rate than in the active disk model without envelope, could represent the observations equally as well. This type of model with the envelope should be considered a viable alternative in future models of other T Tauri stars. The approach of a disk with a puffed-up inner rim wall and the influence of a stellar companion is also discussed. We also investigate the influence of various fit parameters on the outcome of the radiative transfer modeling. From the study of the silicate emission feature we see evidence for dust evolution in a T Tauri star, with a decreasing fraction of small amorphous and an increasing fraction of crystalline particles closer to the star.
Astronomy and Astrophysics
- Pub Date:
- February 2008
- infrared: stars;
- accretion disks;
- stars: planetary systems: protoplanetary disks;
- radiative transfer;
- instrumentation: interferometers;
- 19 pages, 23 figures