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The Mid-infrared Evolution of the FU Orionis Disk

Green, Joel D. and Jones, Olivia C. and Keller, Luke D. and Poteet, Charles A. and Yang, Yao-Lun and Fischer, William J. and Evans, Neal J., II and Sargent, Benjamin A. and Rebull, Luisa M. (2016) The Mid-infrared Evolution of the FU Orionis Disk. Astrophysical Journal, 832 (1). Art. No. 4. ISSN 0004-637X.

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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 μm. In particular, the continuum shortward of the silicate emission complex at 10 μm exhibits a ~12% (~3σ) 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 μm 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Poteet, Charles A.0000-0003-4845-7483
Fischer, William J.0000-0002-3747-2496
Evans, Neal J., II0000-0001-5175-1777
Rebull, Luisa M.0000-0001-6381-515X
Additional Information:© 2016 The American Astronomical Society. Received 2016 June 28; revised 2016 September 1; accepted 2016 September 5; published 2016 November 10. We thank L. Andrew Helton, Sachin Shenoy, James DeBuizer, William Vacca, Joseph Adams, Paule Sonnentrucker, Andrea Banzatti, Miguel Requena-Torres, Klaus Pontoppidan, and Alexander Hubbard for helpful discussions of our results. We thank the SOFIA Science Center (USRA) for data reduction and analysis support. This work is based in part on observations made with 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. Partial support for this work was provided by NASA through award #NAS2-97001, SOF 04-0146 issued by USRA. We acknowledge the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this work, and in particular observer "DUBF" Franky Dubois. The work of WJF was supported by an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center, administered by the Universities Space Research Association under contract with NASA. OCJ acknowledges NASA grant NNX14AN06G. This research has made use of NASA's Astrophysics Data System Bibliographic Services. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Deutsches SOFIA Institut (DSI)50 OK 0901
USRASOF 04-0146
NASA Postdoctoral ProgramUNSPECIFIED
Subject Keywords:accretion, accretion disks – infrared: stars – planets and satellites: formation – stars: formation – stars: protostars – stars: variables: T Tauri, Herbig Ae/Be
Issue or Number:1
Record Number:CaltechAUTHORS:20161117-121733872
Persistent URL:
Official Citation:Joel D. Green et al 2016 ApJ 832 4
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72122
Deposited By: Tony Diaz
Deposited On:17 Nov 2016 20:55
Last Modified:07 Nov 2019 00:13

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