2007ApJ...670.1188L

We have mapped the protostellar jet HH 211 in 342 GHz continuum, SiO (J=8-7), and CO (J=3-2) emission at ∼1" resolution with the Submillimeter Array. Thermal dust emission is seen in continuum at the center of the jet, tracing an envelope and a possible optically thick compact disk (with a size <130 AU) around the protostar. A knotty jet is seen in CO and SiO as in H₂, but extending closer to the protostar. It consists of a chain of knots on each side of the protostar, with an interknot spacing of ∼2"-3" or 600-900 AU and the innermost pair of knots at only ∼1.7" or 535 AU from the protostar. These knots likely trace unresolved internal (bow) shocks (i.e., working surfaces) in the jet, with a velocity range up to ∼25 km/s. The two-sided mass-loss rate of the jet is estimated to be ~(0.7-2.8)x10^–6 M_☉/yr. The jet is episodic, precessing, and bending. A velocity gradient is seen consistently across two bright SiO knots (BK3 and RK2) perpendicular to the jet axis, with ∼1.5±0.8 km/s at ∼30±15 AU, suggesting the presence of jet rotation. The launching radius of the jet, derived from the potential jet rotation, is ∼0.15-0.06 AU in the inner disk.