SOFIA/FORCAST observations of the luminous blue variable candidates MN 90 and HD 168625

Ryan A. Arneson, Dinesh Shenoy, Nathan Smith, Robert D. Gehrz

Research output: Contribution to journalArticlepeer-review

Abstract

We present SOFIA/FORCAST imaging of the circumstellar dust shells surrounding the luminous blue variable (LBV) candidates MN 90 and HD 168625 to quantify the mineral abundances of the dust and to constrain the evolutionary state of these objects. Our image at 37.1 µm of MN 90 shows a limb-brightened, spherical dust shell. A least-squares fit to the spectral energy distribution of MN 90 yields a dust temperature of 59 ± 10 K, with the peak of the emission at 42.7 µm. Using 2-Dust radiative transfer code, we estimate for MN 90 that mass-loss occurred at a rate of (7.3 ± 0.4) × 107 M☉ yr1 × (vexp/50 km s1 ) to create a dust shell with a dust mass of (3.2 ± 0.1) × 102 M☉. Our images between 7.7 - 37.1 µm of HD 168625 complement previously obtained mid-IR imaging of its bipolar nebulae. The SOFIA/FORCAST imaging of HD 168625 shows evidence for the limb-brightened peaks of an equatorial torus. We estimate a dust temperature of 170 ± 40 K for the equatorial dust surrounding HD 168625, with the peak of the emission at 18.3 µm. Our 2-Dust model for HD 168625 estimates that mass-loss occurred at a rate of (3.2 ± 0.2) × 107 M☉ yr1 to create a dust torus/shell with a dust mass of (2.5 ± 0.1) × 103 M☉.

Original languageEnglish (US)
JournalUnknown Journal
StatePublished - Jul 23 2018

Keywords

  • Stars: circumstellar matter
  • Stars: individual: HD168625
  • Stars: individual: MN90
  • Stars: mass-loss
  • Stars: massive

ASJC Scopus subject areas

  • General

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