Superoutburst of CR Bootis: Estimation of Mass Ratio of a typical AM CVn star by Stage A Superhumps
| Autor: | Daisaku Nogami, Aleksei A. Sosnovskij, Franz-Josef Hambsch, Taichi Kato, Nikolai Pit, Arto Oksanen, Seiichiro Kiyota, Alex Baklanov, Kazuki Maeda, Kiyoshi Kasai, Lewis M. Cook, Yuki Sugiura, Risa Matsuda, Tomohito Ohshima, Naoto Kojiguchi, Kirill A. Antonyuk, Katsura Matsumoto, Nao Takeda, Daiki Fukushima, Gianluca Masi, Pavol A. Dubovsky, Aleksandr Sklyanov, Julia V. Babina, Yutaka Maeda, Hiroshi Itoh, Elena P. Pavlenko, Akira Imada, Shawn Dvorak, Rudolf Novak, Colin Littlefield, Kazunari Masumoto, Keisuke Isogai, Oksana I. Antonyuk, Miho Kawabata |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
010308 nuclear & particles physics FOS: Physical sciences Astronomy and Astrophysics Astrophysics Radius Star (graph theory) Mass ratio Orbital period 01 natural sciences Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences Precession Stage (hydrology) Variation (astronomy) 010303 astronomy & astrophysics Dwarf nova Solar and Stellar Astrophysics (astro-ph.SR) |
| Popis: | We report on two superoutbursts of the AM CVn-type object CR Boo in 2014 April--March and 2015 May--June. A precursor outburst acompanied both of these superoutbursts. During the rising branch of the main superoutburst in 2014, we detected growing superhumps (stage A superhumps) whose period was $0.017669(24)$ d. Assuming that this period reflects the dynamical precession rate at the radius of the 3:1 resonance, we could estimate the mass ratio ($q=M_2/M_1$) of 0.101(4) by using the stage A superhump period and the orbital one of 0.0170290(6) d. This mass ratio is consistent with that expected by the theoretical evolutionary model of AM CVn-type objects. The detection of precursor outbursts and stage A superhumps is the second case in AM CVn-type objects. There are two interpretations of the outbursts of AM CVn-type objects. One is a dwarf nova (DN) outbursts analogy, which is caused by thermal and tidal instabilities. Another is the VY Scl-type variation, which is caused by the variation of the mass-transfer rate of the secondary. This detection of the superhump variations strongly suggests the former interpretation. 13 pages, 6 figures |
| Databáze: | OpenAIRE |
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