Infall and Outflow around the HH 212 Protostellar System

HH 212 is a highly collimated jet discovered in H2 powered by a young Class 0source, IRAS 05413-0104, in the L1630 cloud of Orion. We have mapped around itin 1.33 mm continuum, 12CO ($J=2-1$), 13CO ($J=2-1$), C18O ($J=2-1$), and SO($J_K = 6_5-5_4$) emission at $\sim$ \arcs{2.5} resolution with theSubmillimeter Array. A dust core is seen in the continuum around the source. Aflattened envelope is seen in C18O around the source in the equatorperpendicular to the jet axis, with its inner part seen in 13CO. The structureand kinematics of the envelope can be roughly reproduced by a simple edge-ondisk model with both infall and rotation. In this model, the density of thedisk is assumed to have a power-law index of $p=-1.5$ or -2, as found in otherlow-mass envelopes. The envelope seems dynamically infalling toward the sourcewith slow rotation because the kinematics is found to be roughly consistentwith a free fall toward the source plus a rotation of a constant specificangular momentum. A 12CO outflow is seen surrounding the H2 jet, with a narrowwaist around the source. Jetlike structures are also seen in 12CO near thesource aligned with the H2 jet at high velocities. The morphologicalrelationship between the H2 jet and the 12CO outflow, and the kinematics of the12CO outflow along the jet axis are both consistent with those seen in ajet-driven bow shock model. SO emission is seen around the source and the H2knotty shocks in the south, tracing shocked emission around them.Comment: 17 pages, 11 figures, Accepted by the Ap