HH 212: Submillimeter array observations of a remarkable protostellar jet

[[abstract]]HH 212 is a nearby (460 pc) protostellar jet discovered in H-2 powered by a Class 0 source, IRAS 05413 - 0104. We have mapped it in 850 mu m continuum, SiO(J = 8-7), CO(J = 3-2), SO(N-J =8(9)-7(8) ), HCO+(J = 4-3), and (HCO+)-C-13(J = 4-3) emission simultaneously at similar to 1 '' resolution with the Submillimeter Array. Thermal dust emission is seen in continuum around the source, mainly arising from an inner envelope and a possible disk. The inner envelope is also seen with rotation in CO and HCO+ ,and probably in SO. Like H (2) emission, CO and SiO emission are seen along the jet axis but extending closer to the source, tracing the bow shocks and the continuous structures in between. SO emission is seen forming a jetlike structure extending from the source, likely tracing the jet near the launching region. The jet is episodic and bending. It may also be slightly precessing. A hint of jet rotation is also seen across the jet axis. Internal outflow shells are seen in CO and HCO+ associated with the bow shocks in the inner part of the jet. The bases of the HCO+ shells are seen with a hint of rotation, probably consisting mainly of the material extending from the inner envelope and even the possible disk. The bases of the outflow shells are also seen in (HCO+)-C-13 and even the continuum, probably tracing the dense material extending from around the same regions.[[fileno]]2010504010062[[department]]天文