Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-04-24
Astron.Astrophys. 405 (2003) 597-606
Astronomy and Astrophysics
Astrophysics
Accepted for publication in Astronomy & Astrophysics
Scientific paper
10.1051/0004-6361:20030606
The two-layer disk models of Chiang & Goldreich (1997, henceforth CG) and its derivatives are popular among astronomers because of their simplicity and the clear predictions they make for the SEDs of T Tauri stars and Herbig Ae/Be stars. Moreover, they can be computed quickly, which is a great advantage when fitting observations using automated procedures. In this paper we wish to assess the accuracy and reliability of 2-layer models, by comparing them to detailed vertical structure models with accurate 1+1D radiative transfer. We focus on the shape of the SED, and the predicted height and "flaring index" of the disk. We first consider models where scattering is set to zero. We find that 2-layer models overestimate significantly the near-infrared flux, and we suggest a simple way of correcting this effect, at least in part. At longer wavelengths, the SED of two-layer models often show a two-bump structure, which is absent in 1+1D models. Nevertheless, overall agreement is reasonably good, and the differences are in most cases within 30%. At (sub)-mm wavelengths the differences may even be less. The shape of the disk, as measured by its pressure and surface scale height and by the flaring angle are also well reproduced by two-layer models. When scattering is included in the 1+1D models, the differences become larger, especially in the near-infrared. We suggest simple ways to include scattering in two-layer models and discuss their reliability. We do not compare the two-layer models to full 2-D/3-D models, so the conclusions remain valid only within the annulus-by-annulus approximation.
Dullemond Cornelis Petrus
Natta Antonella
No associations
LandOfFree
An analysis of two-layer models for circumstellar disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An analysis of two-layer models for circumstellar disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An analysis of two-layer models for circumstellar disks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-518968