DG Tau B ALMA observations

To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outflow sources in Taurus, we report on new ALMA Band 6 (1.3mm) observations with 0.15" (20au) resolution toward the embedded young star DG Tau B. Images of the continuum emission reveals a dust disk with rings and, putatively, a leading spiral arm.

The disk, as well as the prominent outflow cavities, are detected in CO, H_2_CO, CS, and CN; instead, they remain undetected in SO_2_, HDO, and CH_3_OH. From the absorption of the back-side outflow, we inferred that the disk emission is optically thick in the inner 50au. This morphology explains why no line emission is detected from this inner region and poses some limitations toward the calculation of the dust mass and the characterization of the inner gaseous disk.