Radio and Optical Observations of DG Tau B

TL;DR

This study uses radio observations to measure the proper motions of DG Tau B, revealing its dynamic outflows and suggesting the exciting source differs from nearby infrared objects, advancing understanding of young stellar objects.

Contribution

First measurement of DG Tau B's proper motions using VLA data, clarifying its outflow asymmetry and source identification.

Findings

Proper motions consistent with DG Tau within errors

Detected asymmetric radio ejection event in 1994

Radio source likely traces the exciting star, not the infrared object

Abstract

DG Tau B is a Class I young stellar source that drives the asymmetric HH 159 bipolar jet. At optical wavelengths it is obscured by circumstellar optically-thick material. Using VLA and JVLA observations, we determine for the first time the proper motions of this source and find them to be consistent, within error, with those of the nearby young star DG Tau. We also discuss an ejection event that is evident in the 1994 VLA data. As the optical and molecular outflows, this ejection traced in the radio continuum is markedly asymmetric and was detected only to the NW of the star. We propose that this knot, no longer detectable in the radio, could be observed in future optical images of DG Tau B. The positions of the VLA source and of a nearby infrared object are not coincident and we suggest that the VLA source traces the exciting object, while the infrared source could be a reflection lobe.