Light-curve syntheses for close binary systems: Modeling spiral waves in an elliptical disk around a white dwarf

We present an algorithm for synthesizing the light curve of a close binary consisting of a normal star (a red dwarf that fills its Roche lobe) and a spherical star (a white dwarf). The spherical component is surrounded by an elliptical accretion disk with a complex shape: it is geometrically thin ne...

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Bibliographic Details
Published in:Astronomy reports 2005-10, Vol.49 (10), p.783-800
Main Author: Khruzina, T S
Format: Article
Language:English
Subjects:
Accretion
Accretion disks
Algorithms
Astronomy
Binary systems
Disks
IP (Internet Protocol)
Orbitals
Outbursts
Spirals
Stars
Stars & galaxies
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Summary:We present an algorithm for synthesizing the light curve of a close binary consisting of a normal star (a red dwarf that fills its Roche lobe) and a spherical star (a white dwarf). The spherical component is surrounded by an elliptical accretion disk with a complex shape: it is geometrically thin near the spherical star and geometrically thick at the edge of the disk. An additional complication is presented by the presence of a one-or two-armed spiral pattern at the inner surface of the disk. The maximum height of the spiral arm above the disk surface is located at ~9 R d , and the height decreases exponentially as the arm approaches the inner regions of the disk. Shielding of the inner hot parts of the disk by the crests of the spirals results in the formation of 'steps' in out-of-eclipse parts of the orbital light curves. The algorithm takes into account the presence of a 'hot line' by the lateral surface of the disk, making it possible to model binary systems in both quiescence and outburst. In the latter case, the hot line degenerates into a small bulge at the outer lateral surface of the disk, which can be considered an analog of a hot spot. The algorithm was applied to the orbital light curve of the cataclysmic binary IP Peg during its October 30, 2000, outburst. To explain the variations of the out-of-eclipse brightness of the system during the outburst, it is necessary to include the presence of a one-armed spiral wave at the inner surface of the disk, close to the periastron of the elliptical disk. We have obtained the parameters of IP Peg during the outburst for various models of the system.
ISSN:1063-7729
1562-6881
DOI:10.1134/1.2085249