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  • Imada, Akira; Kato, Taichi; Isogai, Keisuke; Franz-Josef Hambsch; Dubovsky, Pavol A; Kudzej, Igor; Pickard, Roger D; Akazawa, Hidehiko; Kasai, Kiyoshi; Itoh, Hiroshi; Cook, Lewis M; Kiyota, Seiichiro

    arXiv.org, 11/2017
    Paper, Journal Article

    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 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 the previous observations regarding long-lasting stage A superhumps, a time scale of stage A superhumps is likely to be determined by the mass ratio of the system and the temperature of the accretion disk.