THE KEPLER LIGHT CURVE OF V344 Lyrae: CONSTRAINING THE THERMAL-VISCOUS LIMIT CYCLE INSTABILITY

Journal Article · Mon Dec 20 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/725/2/1393· OSTI ID:21476705

Cannizzo, J K ^[1]; Still, M D ^[2]; Howell, S B ^[3]; Wood, M A ^[4]

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1. CRESST/Joint Center for Astrophysics, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States)
2. Bay Area Environmental Research Inst., Inc., 560 Third St. W, Sonoma, CA 95476 (United States)
3. National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
4. Department of Physics and Space Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901 (United States)

We present time-dependent modeling based on the accretion disk limit cycle model for a 270 d light curve of the short-period SU UMa-type dwarf nova V344 Lyr taken by Kepler. The unprecedented precision and cadence (1 minute) far surpass that generally available for long-term light curves. The data encompass two superoutbursts and 17 normal (i.e., short) outbursts. The main decay of the superoutbursts is nearly perfectly exponential, decaying at a rate {approx}12 d mag{sup -1}, while the much more rapid decays of the normal outbursts exhibit a faster-than-exponential shape. Our modeling using the basic accretion disk limit cycle can produce the main features of the V344 Lyr light curve, including the peak outburst brightness. Nevertheless, there are obvious deficiencies in our model light curves. (1) The rise times we calculate, both for the normal and superoutbursts, are too fast. (2) The superoutbursts are too short. (3) The shoulders on the rise to superoutburst have more structure than the shoulders in the observed superoutbursts and are too slow, comprising about a third to half of the total viscous plateau, rather than the {approx}10% observed. However, one of the {alpha}{sub cold} {r_reversible} {alpha}{sub hot} interpolation schemes we investigate (one that is physically motivated) does yield longer superoutbursts with suitably short, less structured shoulders.

• OSTI ID: 21476705
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 725; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ATTRACTORS
BINARY STARS
BRIGHTNESS
DWARF STARS
ERUPTIVE VARIABLE STARS
INTERPOLATION
LIMIT CYCLE
MATHEMATICAL SOLUTIONS
NOVAE
NUMERICAL SOLUTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS
TIME DEPENDENCE
VARIABLE STARS
WHITE DWARF STARS