Publication details

Superoutburst of CR Bootis: Estimation of mass ratio of a typical AM CVn star by stage A superhumps

Authors	ISOGAI Keisuke KATO Taichi OHSHIMA Tomohito KASAI Kiyoshi OKSANEN Arto MASUMOTO Kazunari FUKUSHIMA Daiki MAEDA Kazuki KAWABATA Miho MATSUDA Risa KOJIGUCHI Naoto SUGIURA Yuki TAKEDA Nao MATSUMOTO Katsura ITOH Hiroshi PAVLENKO Elena P. ANTONYUK Kirill ANTONYUK Oksana PIT Nikolai SOSNOVSKIJ Aleksei BAKLANOV Alex BABINA Julia SKLYANOV Aleksandr KIYOTA Seiichiro HAMBSCH Franz-Josef LITTLEFIELD Colin MAEDA Yutaka COOK Lewis M. MASI Gianluca DUBOVSKY Pavol A. NOVÁK Rudolf DVORAK Shawn IMADA Akira NOGAMI Daisaku
Year of publication	2016
Type	Article in Periodical
Magazine / Source	PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
MU Faculty or unit	Faculty of Science
Citation
Web	https://academic.oup.com/pasj/article-abstract/68/4/64/2223334/Superoutburst-of-CR-Bootis-Estimation-of-mass?redirectedFrom=fulltext
Doi	http://dx.doi.org/10.1093/pasj/psw063
Field	Astronomy and astrophysics
Keywords	accretion; accretion disks; novae; cataclysmic variables; stars; dwarf novae; stars; individual (CR Bootis)
Description	We report on two superoutbursts of the AM CVn-type object CR Boo in 2014 April-March and 2015 May-June. A precursor outburst accompanied both of these superoutbursts. During the rising branch of the main superoutburst in 2014, we detected growing super-humps (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 period of 0.0170290(6) d. This mass ratio is consistent with that expected from 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 suggets that the outbursts are caused by thermal and tidal instabilities. Another is the VY Scl-type variation, which suggests that the outbursts are caused by the variation of the mass-transfer rate of the secondary. This detection of the superhump variations strongly supports the former interpretation.