New MMT/MIRAC (9-11 μm), SOFIA/FORCAST (11-37 μm), and Herschel/PACS (70 and 160 μm) infrared (IR) imaging and photometry is presented for three famous OH/IR red supergiants (NML Cyg, VX Sgr, and S Per) and two normal red supergiants (RS Per and T Per). We model the observed spectral energy distributions (SEDs) using radiative-transfer code DUSTY. Azimuthal average profiles from the SOFIA/FORCAST imaging, in addition to dust mass distribution profiles from DUSTY, constrain the mass-loss histories of these supergiants. For all of our observed supergiants, the DUSTY models suggest that constant mass-loss rates do not produce enough dust to explain the observed infrared emission in the stars' SEDs. Combining our results with Shenoy et al. (Paper I), we find mixed results with some red supergiants showing evidence for variable and high mass-loss events while others have constant mass loss over the past few thousand years.
Bibliographical noteFunding Information:
Based on observations obtained with: (1) the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart; and (2) the MMT Observatory on Mt. Hopkins, AZ, a joint facility of the Smithsonian Institution and the University of Arizona.
We thank Rubab Khan for discussion on χ2-minimization of DUSTY models. This work has used unpublished data from Michael Schuster’s PhD thesis, which is available through the SAO/NASA Astrophysics Data System (ADS) at http:// adsabs.harvard.edu/abs/2007PhDT........28S. Financial support for this work was provided by NASA through awards SOF 03 0082 and SOF 04 0013 to R M Humphreys issued by USRA. R.D.G. acknowledges support from NASA and the United States Air Force.
© 2018. The American Astronomical Society. All rights reserved.
Copyright 2018 Elsevier B.V., All rights reserved.
- stars: individual (NML Cyg, RS Per, S Per, T Per, VX Sgr)
- stars: mass-loss