Revealing and Investigating the Shocks and Outflow Properties of HOPS 361

We present a SOFIA far-IR and HST near-IR study of NGC 2071, a system of at least two outflows from a small group of intermediate- to low-luminosity protostars: HOPS 361-A and HOPS 361-C, the latter of which is a binary (Tobin et al. 2020). Previous observations of this region revealed a powerful bipolar outflow (Bally 1982; Wootten et al. 1984). More recently this outflow has been mapped in near-IR and mid-IR H2 line (Walther & Geballe 2019 and Neufeld et al. 2009) and by ALMA in the CO (J=3-2) line (Ye et al. in prep).

The far-IR SOFIA-GREAT observations detect gas heated and accelerated by shocks. GREAT detected far-IR transitions of [OI] at 63 microns and three CO transitions (9-8, 13-12, and 22-21) tracing hot gas in the outflow. The resolved line profiles can be decomposed into distinct components which provide radial velocities for the gas in the jets, in the terminal shocks, and in the swept-up gas. The WFC3/IR data resolve [FeII] and Paschen Beta emission from J-type shocks in the outflows and provide estimates of the mechanical luminosity of outflow. By comparing the HST observation to a 2009 F160W image, the proper motions of the shocks are measured. We show that by combining the high spatial resolution HST and high spectral resolution SOFIA data, we constrain the 3D motions of shocks in the outflow. In combination with the near and far-IR line profiles, these motions provide estimates of the shock velocities as well as mass, momentum, and energy flows through the shocks. We present current results from the data and discuss how these data are leading to some of the most detailed measurement to date of feedback from a system of low to intermediate mass protostars.