ABSTRACT. 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 (N_J = 5₆-4₅) emission at ~25 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.

Subject headings: ISM: individual (HH 212); ISM: jets and outflows; stars: formation

Print publication: Issue 1 (2006 March 1)
Received 2005 September 12, accepted for publication 2005 November 1