SOFIA/FORCAST Observations of the Luminous Blue Variable Candidates MN 90 and HD 168625

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 micron 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 \pm 10 K, with the peak of the emission at 42.7 micron. Using 2-Dust radiative transfer code, we estimate for MN 90 that mass-loss occurred at a rate of (7.3 \pm 0.4)x10^-7 M_sun/yr x (v_exp/50 km/s) to create a dust shell with a dust mass of (3.2 \pm 0.1)x10^-2 M_sun. Our images between 7.7 - 37.1 micron 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 \pm 40 K for the equatorial dust surrounding HD 168625, with the peak of the emission at 18.3 micron. Our 2-Dust model for HD 168625 estimates that mass-loss occurred at a rate of (3.2 \pm 0.2)x10^-7 M_sun/yr to create a dust torus/shell with a dust mass of (2.5 \pm 0.1)x10^-3 M_sun.

arXiv comment17 pages, 5 figures, accepted for publication in ApJ

References in corpus (40)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Spitzer Space Telescope Mission
• Interstellar Dust Grains
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
• The Infrared Astronomical Mission AKARI
• A Three-Dimensional Map of Milky-Way Dust
• Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE passbands
• Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy
• Line derived infrared extinction towards the Galactic Center
• The Missing Luminous Blue Variables and the Bistability Jump
• Luminous Blue Variables are Antisocial: Their Isolation Implies that they are Kicked Mass Gainers in Binary Evolution
• A Mid-Infrared Imaging Survey of Proto-Planetary Nebula Candidates
• MESS (Mass-loss of Evolved StarS), a Herschel Key Program
• A Hidden Population of Massive Stars with Circumstellar Shells Discovered with the Spitzer Space Telescope
• Discovery of a nearby twin of SN1987A's nebula around the luminous blue variable HD168625: Was Sk--69 202 an LBV?
• Galactic Twins of the Ring Nebula Around SN1987A and a Possible LBV-like Phase for Sk-69 202
• First Science Observations with SOFIA/FORCAST: The FORCAST Mid-infrared Camera
• A Blast Wave from the 1843 Eruption of Eta Carinae
• Revealing evolved massive stars with Spitzer
• The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor
• 2-Dust : a Dust Radiative Transfer Code for an Axisymmetric System
• A Catalog of MIPSGAL Disk and Ring Sources
• SOFIA/FORCAST Imaging of the Circumnuclear Ring at the Galactic Center
• Subarcsecond Mid-IR Structure of the Dust Shell around IRAS 22272+5435
• Two Subclasses of Proto-Planetary Nebulae: Model Calculations
• The first X-ray survey of Galactic Luminous Blue Variables
• Constraints on gamma-ray burst and supernova progenitors through circumstellar absorption lines. (II): Post-LBV Wolf-Rayet stars
• Discovery of an Extended Dust Emission around IRAS 18576+0341 (AFGL 2298) at 10.3 and 18.0 microns: a New Luminous Blue Variable Candidate?
• The Molecular and Dust Envelope of HD 56126
• Herschel/PACS observations of the 69 $\mu m$ band of crystalline olivine around evolved stars
• The Structure of the Homunculus. III. Forming a Disk and Bipolar Lobes in a Rotating Surface Explosion
• Multi-wavelength study of the nebula associated with the galactic LBV candidate HD 168625
• Luminous blue variables: An imaging perspective on their binarity and near environment
• Sher 25: pulsating but apparently alone
• Nature Versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center
• WS1: one more new Galactic bona fide luminous blue variable
• Tracing back the evolution of the candidate LBV HD168625

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