Resolving and Probing the Circumstellar Disk of the Herbig Ae Star MWC 480 at λ = 1.4 mm: Evolved Dust?

University of Illinois, Urbana-Champaign, Urbana, Illinois, United States
The Astrophysical Journal (Impact Factor: 5.99). 11/2006; 651(1):321-327. DOI: 10.1086/507693
Source: arXiv


We present high-resolution 0.45"×0.32" observations from the BIMA array toward the Herbig Ae system MWC 480 in the lambda=1.4 mm dust continuum. We resolve a circumstellar disk of radius ~170 AU and constrain the disk parameters by comparing the observations to flat-disk models. These results show that the typical fit parameters of the disk, such as the mass, MD~0.04-0.18 Msolar, and the surface density power-law index, p=0.5 or 1, are comparable to those of the lower mass T Tauri stars. The dust in the MWC 480 disk can be modeled as processed dust material (beta~0.8), similar to the Herbig Ae star CQ Tau disk; the fitted disk parameters are also consistent with less evolved dust (beta~1.2). The possibility of grain growth in the MWC 480 circumstellar disk is supported by the acceptable fits with beta~0.8. The surface density power-law profiles of p=0.5 and p=1 can be easily fitted to the MWC 480 disk; however, a surface density power-law profile similar to the minimum mass solar nebula model p=1.5 is ruled out at an 80% confidence level.

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