Imaging of the Compact Dust Disk around DG Tauri with 1[arcsec] Resolution

Abstract

We have made aperture synthesis observations of 147 GHz continuum emission from the dust around the young star DG Tau with the Nobeyama Millimeter Array. Using the sparsest AB configuration of the array, we attained a small synthesized beam of 148 × 108 with P.A. = 117°. As a result, a disklike structure of the dust has been successfully resolved. The size of the dust disk is estimated to be 156 × 054 (218 AU × 76 AU) with P.A. = 99°, which is corrected for the synthesized beam pattern and atmospheric seeing. The disk size of the seeing was estimated to be 042 from observations of a pointlike calibrator. Assuming a geometrically thin disk, the radius and inclination angle of the dust disk are calculated to be 109 ± 22 AU and 70° ± 10°, respectively. The total flux density emitted from the dust disk is 186 ± 17 mJy, and the disk mass is calculated to be 0.01-0.06 M☉, using the dust opacity coefficient κν = 0.05-0.02 cm2 g-1. The resolved dust disk is quite consistent with the spectral energy distribution of DG Tau, although the disk radius of 109 AU is slightly larger than the radius of 75 AU derived by Adams, Emerson, & Fuller. Our results, however, do not agree with the infalling envelope model proposed by Calvet and coworkers, where the major part of the flux density in the millimeter to mid-infrared range comes from the large envelope.