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Spectrum of the WZ Sge-type dwarf nova PQ And in outburst

ATel #13776; Keisuke Isogai (Kyoto University, Okayama Observatory), Naoto Kojiguchi, Yasuyuki Wakamatsu, Yusuke Tampo and Masaaki Shibata (Kyoto University)
on 3 Jun 2020; 13:14 UT
Credential Certification: Keisuke Isogai (isogai@kusastro.kyoto-u.ac.jp)

Subjects: Optical, Cataclysmic Variable, Transient, Variables

We report on the spectrum of the WZ Sge-type dwarf nova PQ And in outburst. We obtained the spectrum on 2020-06-02.78 UT by using a fiber-fed integral field spectrograph (KOOLS-IFU; Matsubayashi et al. 2019) mounted on the 3.8-m telescope Seimei at Okayama Observatory of Kyoto University.

PQ And is known as a most likely WZ Sge-type dwarf which showed the historical outbursts in 1938, 1967, 1988 (Richter 2004). According to IAUC 4620 , a spectrum in the 1988 outburst was taken around 11.0 mag. Although they reported "A preliminary inspection of the object's spectrum at the time apparently showed the presence of strong O III emission", the data was lost due to computer problems.

A new outburst of PQ And was detected at 10.48 mag on 2020-05-28.276 UT by Kenji Hirosawa (vsnet-alert 24301). According to our photometric data taken by the 40-cm telescope of Kyoto University, the object was faded to 11.8 +/- 0.1 mag on 2020-06-02.78 UT. We also obtained a spectrum simultaneously. Our spectrum showed Balmer absorption lines with emission cores, which are typically seen in dwarf nova outbursts. There are no signals of O III, which were reported in the 1988 outburst. In 1988, this object was considered as a classical nova at first. Thus, they might have detected a cosmic ray or noise as O III due to psychological bias. We note that our spectrum was taken in Astronomical twilight and the elevation of the object was 19 degrees. Thus the spectrum is contaminated by telluric absorption and sunlight.

spectrum