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The FU Orionis outburst as a thermal accretion event: Observational constraints for protostellar disk modelsThe results of the time-dependent disk models developed in Bell & Lin are compared with observed properties of FU Orionis variables. Specific models are fit to the light curves of Fu Ori, V1515 Cyg, and V1057 Cyg. The slow risetime of V1515 Cyg can be matched by a self-regulated outburst model. The rapid risetimes of FU Ori and V1057 Cyg can be fitted with the application of modest perturbations to the disk surface density. Model disks display spectral features characteristic of observed objects. The color evolution of V1057 Cyg is naturally explained if mass flux drops in the inner disk (r less than 1/4 AU) while remaining steady in the outer disk. The decrease in optical line width (rotational velocity) observed during the decay of V1057 Cyg may be accounted for by an outward-propagating ionization front. We predict that before final decay to the quiescent phase, short-wavelength line widths (lambda less than 1.5 microns) will again increase. It is suggested that FU Orionis outbursts primarily occur to systems during the embedded phase with ages less than several times 10(exp 5) yr.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Bell, K. R. (Universtiy of California, Santa Cruz, California United States)
Lin, D. N. C. (Universtiy of California, Santa Cruz, California United States)
Hartmann, L. W. (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts United States)
Kenyon, S. J. (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts United States)
Date Acquired
August 16, 2013
Publication Date
May 1, 1995
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 444
Issue: 1
ISSN: 0004-637X
Subject Category
Funding Number(s)
Distribution Limits