A MODEL FOR (QUASI-)PERIODIC MULTIWAVELENGTH PHOTOMETRIC VARIABILITY IN YOUNG STELLAR OBJECTS

Journal Article · Thu Sep 01 00:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/828/1/42· OSTI ID:22667469

Kesseli, Aurora Y. ^[1]; Petkova, Maya A.; Wood, Kenneth; Gregory, Scott G. ^[2]; Whitney, Barbara A. ^[3]; Hillenbrand, L. A. ^[4]; Stauffer, J. R.; Morales-Calderon, M.; Rebull, L. ^[5]; Alencar, S. H. P., ^[6]

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1. Boston University, 725 Commonwealth Ave, Boston, MA 02215 (United States)
2. SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9AD (United Kingdom)
3. Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St, Madison, WI 53706 (United States)
4. Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States)
5. Spitzer Science Center, California Institute of Technology, CA 91125 (United States)
6. Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil)

We present radiation transfer models of rotating young stellar objects (YSOs) with hot spots in their atmospheres, inner disk warps, and other three-dimensional effects in the nearby circumstellar environment. Our models are based on the geometry expected from magneto-accretion theory, where material moving inward in the disk flows along magnetic field lines to the star and creates stellar hot spots upon impact. Due to rotation of the star and magnetosphere, the disk is variably illuminated. We compare our model light curves to data from the Spitzer YSOVAR project to determine if these processes can explain the variability observed at optical and mid-infrared wavelengths in young stars. We focus on those variables exhibiting “dipper” behavior that may be periodic, quasi-periodic, or aperiodic. We find that the stellar hot-spot size and temperature affects the optical and near-infrared light curves, while the shape and vertical extent of the inner disk warp affects the mid-IR light curve variations. Clumpy disk distributions with non-uniform fractal density structure produce more stochastic light curves. We conclude that magneto-accretion theory is consistent with certain aspects of the multiwavelength photometric variability exhibited by low-mass YSOs. More detailed modeling of individual sources can be used to better determine the stellar hot-spot and inner disk geometries of particular sources.

• OSTI ID: 22667469
• Journal Information: Astrophysical Journal, Vol. 828, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ATMOSPHERES
AUGER ELECTRON SPECTROSCOPY
COMPARATIVE EVALUATIONS
DENSITY
DISTRIBUTION
HOT SPOTS
MAGNETIC FIELDS
MASS
PERIODICITY
PHOTOMETRY
ROTATION
SIMULATION
STAR EVOLUTION
STARS
STOCHASTIC PROCESSES
THREE-DIMENSIONAL CALCULATIONS
VISIBLE RADIATION
WAVELENGTHS