  HH 212 is a highly collimated jet discovered in H2 powered by a young Class 0
source, IRAS 05413-0104, in the L1630 cloud of Orion. We have mapped around it
in 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 the
Submillimeter Array. A dust core is seen in the continuum around the source. A
flattened envelope is seen in C18O around the source in the equator
perpendicular to the jet axis, with its inner part seen in 13CO. The structure
and kinematics of the envelope can be roughly reproduced by a simple edge-on
disk model with both infall and rotation. In this model, the density of the
disk is assumed to have a power-law index of $p=-1.5$ or -2, as found in other
low-mass envelopes. The envelope seems dynamically infalling toward the source
with slow rotation because the kinematics is found to be roughly consistent
with a free fall toward the source plus a rotation of a constant specific
angular momentum. A 12CO outflow is seen surrounding the H2 jet, with a narrow
waist around the source. Jetlike structures are also seen in 12CO near the
source aligned with the H2 jet at high velocities. The morphological
relationship between the H2 jet and the 12CO outflow, and the kinematics of the
12CO outflow along the jet axis are both consistent with those seen in a
jet-driven bow shock model. SO emission is seen around the source and the H2
knotty shocks in the south, tracing shocked emission around them.

Astrophysics