The Outflow of the B335 Protostar. II. After the Outburst

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Abstract
The Barnard 335 (B335) protostar has recently undergone a major, still ongoing, outburst detected in scattered light from its outflow cavity, offering a rare opportunity to study its impact on a protostellar jet. We use James Webb Space Telescope (JWST) NIRCam photometry of background stars behind B335 from 2.7 to 4.4 μ m to map extinction and H 2 O ice absorption, showing that the outflow has carved a cavity in the molecular core. We measure proper motions of shock fronts emerging from the protostar of 131–227 km s −1 . The kinematic age of the most prominent shock front, 3E, corresponds to the early phase of the current outburst. JWST/NIRSpec Integral Field Unit data show that the youngest shock, 2E, exhibits ionic lines but no molecular emission. Shock 3E shows strong CO emission together with H 2 and [Fe ii ], whereas older shocks show weaker CO and are dominated by H 2 and [Fe ii ]. The feature 0E, closest to the protostar, appears to be a stationary shock. CO-line-removed spectra near the protostar show that the unsaturated absorption features of 13 CO 2 , OCN – , and OCS increase strongly toward the source. The ice properties are otherwise similar to those along lower-extinction sight lines. In the central bipolar reflection nebula, CO gas is seen in scattered emission from the immediate protostellar surroundings, but a few arcseconds farther out, absorption by cooler CO gas in the outflow cavity is detected.
Funding Information
  • National Aeronautics and Space Administration (NAS5-02105 (M. Rieke University of Arizona PI).)

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