The 2015 superoutburst of QZ Virginis: Detection of growing superhumps between the precursor and main superoutburst. (22nd July 2017)

• Record Type: Journal Article
• Authors: Imada, Akira; Kato, Taichi; Isogai, Keisuke; Hambsch, Franz-Josef; Dubovsky, Pavol A.; Kudzej, Igor; Pickard, Roger D.; Akazawa, Hidehiko; Kasai, Kiyoshi; Itoh, Hiroshi; Cook, Lewis M.; Kiyota, Seiichiro
• Is Part Of: Publications of the Astronomical Society of Japan. Volume 69:Number 4(2017:Aug.)
• Publication Date: 2017-07-22
• Subjects: accretion, accretion disks -- stars: dwarf novae -- stars: individual (QZ Virginis) -- stars: novae, cataclysmic variables -- stars: oscillations; Astronomy -- Periodicals; 520.5
• DOI: 10.1093/pasj/psx055
• Languages: English
• ISSNs: 0004-6264

Abstract

Abstract: We report on time-resolved photometry of the 2015 February–March superoutburst of QZ Virginis. The superoutburst consisted of a separated precursor, main superoutburst, and rebrightening. We detected superhumps with a period of 0.061181(42) d between the precursor and main superoutburst. Based on analyses of period changes and amplitudes of superhumps, the observed superhumps were identified as growing superhumps (stage A superhumps). The duration of the stage A superhumps was about 5 d, unusually long for SU UMa-type dwarf novae. Using the obtained stage A superhump period, we estimated the mass ratio of QZ Vir to be 0.108(3). This value suggests that QZ Vir is an SU UMa-type dwarf nova evolving toward the period minimum. Based on the present and previous observations regarding long-lasting stage A superhumps, the time scale for stage A superhumps is likely to be determined by the mass ratio of the system and the temperature of the accretion disk.