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Accretion Variability as a Guide to Stellar Mass Assembly

Fischer, William J. and Hillenbrand, Lynne A. and Herczeg, Gregory J. and Johnstone, Doug and Kóspál, Ágnes and Dunham, Michael M. (2022) Accretion Variability as a Guide to Stellar Mass Assembly. . (Unpublished)

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Variable accretion in young stellar objects reveals itself photometrically and spectroscopically over a continuum of timescales and amplitudes. Most dramatic are the large outbursts (e.g., FU Ori, V1647 Ori, and EX Lup type events), but more frequent are the less coherent, smaller burst-like variations in accretion rate. Improving our understanding of time-variable accretion directly addresses the fundamental question of how stars gain their masses. We review variability phenomena, as characterized from observations across the wavelength spectrum, and how those observations probe underlying physical conditions. The diversity of observed lightcurves and spectra at optical and infrared wavelengths defies a simple classification of outbursts and bursts into well-defined categories. Mid-infrared and sub-millimeter wavelengths are sensitive to lower-temperature phenomena, and it is currently unclear if observed flux variations probe similar or distinct physics relative to the shorter wavelengths. We highlight unresolved issues and emphasize the value of spectroscopy, multiwavelength studies, and ultimately patience in using variable accretion to understand stellar mass assembly.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Fischer, William J.0000-0002-3747-2496
Herczeg, Gregory J.0000-0002-7154-6065
Johnstone, Doug0000-0002-6773-459X
Dunham, Michael M.0000-0003-0749-9505
Group:Astronomy Department
Record Number:CaltechAUTHORS:20220517-214248373
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114784
Deposited By: George Porter
Deposited On:18 May 2022 15:53
Last Modified:18 May 2022 15:53

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