HST and SOFIA are embarking on a joint program that focuses on the beginning and the end of stellar evolution. In 2020, two joint Directors' Discretionary pilot programs were approved to showcase the possibilities of multiwavelength science with the Stratospheric Observatory For Infrared Astronomy (SOFIA) and the Hubble Space Telescope (HST). These programs, formed out of a partnership between STScI and USRA, focus on the beginning (PI: Karnath) and end (PI: Goldman) of stellar evolution. 

Joint Observations

Program ID: 75_0056

Principal Investigator: Nicole Karnath (SOFIA)

Title: Investigating the Outflows and Shocks of HOPS 361

Abstract: We propose a HST near-IR + SOFIA far-IR study of NGC 2071, a system of at least two outflows from a small group of intermediate to low luminosity stars. Protostellar outflows are ubiquitous part of the star formation process. They provide a record of variable accretion onto stars, have significant impact on the surrounding molecular cloud, and may disrupt or trigger star formation in molecular clouds. Intermediate-luminosity (30 < L_bol < 1000L_sun) protostars bridge the gap between low- and high-mass star formation, forming stars with masses between 2 and 10 M_sun stars (Di Francesco et al. 1997; Mannings & Sargent 2000). Outflows from these systems of protostars have a significant impact on the surrounding ISM, may play an important role in cloud evolution, and are an important laboratory for understanding the origin of far-IR line emission from outflows. Shock-excited emission lines in the near- and far-IR can be used to study the energetics of outflows and their impact on the surrounding cloud. In this study, WFC3/IR images of [FeII] and Paschen beta lines will trace the shocks in the near-IR. A comparison of these data to WFC3/IR imaging in the F160W band from 2009 will be used to derive proper motions. The intensity of these lines will provide estimates of the mechanical luminosity of the line. SOFIA upGREAT will trace emission from far-IR transitions of [OI] and CO (J=16-15). These lines will provide both radial velocities of the shocked emission as well as measurements of the mass flow and heating by shocks and UV radiation. The combined data will provide 3D velocities of the shocks in the molecular clouds, shock velocities, and mass, energy momentum flows through the shocks, providing one of the most detailed measurements of the feedback from a system of protostars to date. The observations of this relatively nearby system (420 pc, Kounkel et al. 2017) will provide unique information on the outflows in a region that is being increasingly well studied through SOFIA FORCAST and HAWC+ observations, making it a well-characterized template for intermediate-mass star formation.

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Program ID: 75_0057

Principal Investigator: Steven Goldman (Space Telescope Science Institute)

Title: SOFIA and HST Multi-wavelength study of the Symbiotic Mira HM Sge

Abstract: To showcase the capabilities of evolved-star science using the instrument modes of SOFIA and the Hubble Space Telescope (HST), we propose to use FORCAST and EXES aboard SOFIA, and WFC3 and COS aboard HST to probe the quickly-evolving symbiotic system HM Sge. We will use SOFIA to probe the dust and the kinematics of the dense circum-stellar material, and HST to map the gas in the inner nebula and probe the shocked emission. These observations will provide a public dataset that can be used to anchor future observations of HM Sge, a post-outburst symbiotic Mira that displays a wide and diverse range of active astrophysical phenomena. The observations will also demonstrate the possibilities for future observations of other evolved-star systems.

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