1. Superoutburst of SDSS J090221.35+381941.9: First measurement of mass ratio in an AM CVn-type object using growing superhumps
- Author
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Elena P. Pavlenko, Kirill A. Antonyuk, Julia V. Babina, Raul Michel, Sergey Yu. Shugarov, Drahomir Chochol, Nikolaj V. Pit, Enrique de Miguel, Yutaka Maeda, Oksana I. Antonyuk, Gianluca Masi, Seiichiro Kiyota, Pavol A. Dubovsky, Aleksei A. Sosnovskij, D. Denisenko, Arto Oksanen, Kazunari Matsumoto, Miho Kawabata, Patrick Schmeer, Roger D. Pickard, Joseph Ulowetz, Megumi Takenaka, Francesca Nocentini, Alex Baklanov, Colin Littlefield, Arne Henden, William Stein, Shawn Dvorak, Daiki Fukushima, Kazuki Maeda, Igor Kudzej, Risa Matsuda, Rudolf Novak, Hiroshi Itoh, Tomohito Ohshima, Daisuke Daisuke, Ian Miller, Katsura Matsumoto, and Taichi Kato
- Subjects
Physics ,Astrophysics - Solar and Stellar Astrophysics ,Accretion disc ,Space and Planetary Science ,Precession ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Mass ratio ,Orbital period ,Type object ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
We report on a superoutburst of the AM CVn-type object SDSS J090221.35+381941.9 [J0902; orbital period 0.03355(6) d] in 2014 March-April. The entire outburst consisted of a precursor outburst and the main superoutburst, followed by a short rebrightening. During the rising branch of the main superoutburst, we detected growing superhumps (stage A superhumps) with a period of 0.03409(1) d. During the plateau phase of the superoutburst, superhumps with a shorter period (stage B superhumps) were observed. Using the orbital period and the period of the stage A superhumps, we were able to measure the dynamical precession rate of the accretion disk at the 3:1 resonance, and obtained a mass ratio (q) of 0.041(7). This is the first successful measurement of the mass ratio in an AM CVn-type object using the recently developed stage A superhump method. The value is generally in good agreement with the theoretical evolutionary model. The orbital period of J0902 is the longest among the outbursting AM CVn-type objects, and the borderline between the outbursting systems and systems with stable cool disks appears to be longer than had been supposed., Comment: 6 pages, 4 figures, accepted for publication in PASJ
- Published
- 2014
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