Changes in the parameters of the accretion disk around the dwarf nova SDSS J090350.73+330036.1 during an outburst

• Published in: Astronomy reports 2012-11, Vol.56 (11), p.819-842
• Main Authors: Voloshina, I. B., Khruzina, T. S.
• Format: Article
• Language: English
• Subjects: Accretion; Astronomy; Astrophysics; Boundary layers; Double stars; Observations and Techniques; Physics; Physics and Astronomy; Spectrum analysis; Supernovae
• ISSN: 1063-7729; 1562-6881
• DOI: 10.1134/S1063772912110078

R -band photometric light curves of the eruptive eclipsing binary SDSS J090350.73+330036.1 obtained during a superoutburst in May 2010 (JD 2455341-2455347) are analyzed. Observations covering an interval near the outburst maximum and the post-maximum decrease by 0.7 m are presented. Oscillations (superhumps) whose period differs from the orbital period by several percent are observed in the light curve together with eclipses, suggesting that the studied system is a SU UMa dwarf nova. A “spiral arm” model is used to fit the light curves and determine the parameters of the accretion disk and other components of the binary system. Together with a hot line, this model takes into account, geometrical inhomogeneities on the surface of the accretion disk, namely, two thickenings at its outer edge that decrease exponentially in the vertical direction with approach toward the white dwarf. The increase in the R -band flux from the system during the superoutburst mainly results from the enhanced luminosity of the accretion disk due to the increase in its radius by up to ∼0.44 a 0 at the outburst maximum ( a 0 is the component separation), as well as a shallower radial temperature decrease law than in the canonical case. As the superoutburst faded, the disk radius decreased smoothly at the end of our observation (to ∼0.33 a 0 ), the thickness of its outer edge and temperature of its boundary layer decreased, and the parameter α g approached its canonical value. Deviations from the mean brightness of the system as a function of the superhump period P sh are analyzed for each out-of-eclipse set of observations. Various factors affecting the appearance and amplitudes of superhumps in the orbital light curves are considered.