DG-TAURI-B - THE INTERACTION OF AN ATOMIC JET WITH AMBIENT MOLECULAR GAS

We have made high-resolution (4 '') observations of the 2.6 mm continu um and CO (1-0) line emission associated with the young stellar object DG Tau B. The aperture-synthesis CO map clearly shows that redshifted emission is symmetrically distributed about the DG Tau B optical jet and extends at least 6000 AU to the northwest of the unresolved contin uum source. By contrast, blueshifted CO emission is confirmed to a com pact region, which is less than 500 AU in radius. Within 1000 AU of th e star, the redshifted CO emission is elongated, brightest along its c entral axis, and unresolved in the transverse direction. Beyond 1000 A U, the flow broadens and begins to bifurcate. The morphology of the CO emission provides compelling evidence that the extended molecular out flow is driven by the highly collimated atomic jet. The spatial corres pondence between knots in the optical jet and successive broadenings o f the outflow supports the hypothesis that the molecular outflow is pr oduced by the action of multiple working surfaces in a time-varying je t.