THE MID-INFRARED EVOLUTION OF THE FU ORIONIS DISK

Journal Article · Sun Nov 20 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/832/1/4· OSTI ID:22661031

Green, Joel D.; Jones, Olivia C.; Poteet, Charles A.; Sargent, Benjamin A. ^[1]; Keller, Luke D. ^[2]; Yang, Yao-Lun; Evans, II, Neal J. ^[3]; Fischer, William J. ^[4]; Rebull, Luisa M. ^[5]

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1. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
2. Department of Physics and Astronomy, Ithaca College, Ithaca, NY (United States)
3. Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
4. Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
5. IPAC, Pasadena, CA 91125 (United States)

We present new SOFIA-FORCAST observations obtained in 2016 February of the archetypal outbursting low-mass young stellar object FU Orionis, and we compare the continuum, solid-state, and gas properties with mid-infrared data obtained at the same wavelengths in 2004 with Spitzer -IRS. In this study, we conduct the first mid-infrared spectroscopic comparison of an FUor over a long time period. Over a 12-year period, UBVR monitoring indicates that FU Orionis has continued its steady decrease in overall brightness by ∼14%. We find that this decrease in luminosity occurs only at wavelengths ≲20 μ m. In particular, the continuum shortward of the silicate emission complex at 10 μ m exhibits a ∼12% (∼3 σ ) drop in flux density but no apparent change in slope; both the Spitzer and SOFIA spectra are consistent with a 7200 K blackbody. Additionally, the detection of water absorption is consistent with the Spitzer spectrum. The silicate emission feature at 10 μ m continues to be consistent with unprocessed grains, unchanged over 12 years. We conclude that either the accretion rate in FU Orionis has decreased by ∼12–14% over this time baseline or the inner disk has cooled, but the accretion disk remains in a superheated state outside the innermost region.

• OSTI ID: 22661031
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 832; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ACCRETION DISKS
AUGER ELECTRON SPECTROSCOPY
BRIGHTNESS
COMPARATIVE EVALUATIONS
FLUX DENSITY
INTERMEDIATE INFRARED RADIATION
LUMINOSITY
MONITORING
PLANETS
PROTOSTARS
SATELLITES
SILICATES
STAR ACCRETION
STARS
WATER
WAVELENGTHS