Spectroscopic and photometric observations of dwarf nova superoutbursts by the 3.8 m telescope Seimei and the Variable Star Network
Ruiz, Javier; Maehara, Hiroyuki; Namekata, Kosuke; Nogami, Daisaku; Otsuka, Masaaki; Zubareva, Alexandra M.; Okamoto, Soshi; Kawabata, Miho; Maeda, Keiichi; Tampo, Yusuke; Kato, Taichi; Isogai, Keisuke; Kimura, Mariko; Kojiguchi, Naoto; Shibata, Masaaki; Taguchi, Kenta; Itoh, Hiroshi; Matsumoto, Katsura; Nakagawa, Momoka; Dvorak, Shawn; Tordai, Tamás; Vanmunster, Tonny; Kiyota, Seiichiro; Katysheva, Nataly; Shugarov, Sergey Yu; Dubovsky, Pavol A.; Medulka, Tomáš; Hambsch, Franz-Josef; Wakamatsu, Yasuyuki; Pavlenko, Elena P.; Antonyuk, Kirill A.; Antonyuk, Oksana I.; Pickard, Roger D.; Ikonnikova, Natalia P.; Belinski, Alexandr A.; Sosnovskij, Aleksei A.; Babina, Julia V.; Baklanov, Aleksei V.; Maeda, Yutaka; Kudzej, Igor; Stone, Geoffrey; Brincat, Stephen M.; Galdies, Charles; Mizutani, Masanori; Dufoer, Sjoerd; Menzies, Kenneth; Sano, Yasuo; Pit, Nikolaj V.; Burlak, Marina A.; Burgaz, Umut; Nagoshi, Shumpei; Fujii, Daiti; Matsumura, Ryota; Takeuchi, Nodoka; Zenkou, Yuki; Chochol, Drahomír; Moriyama, Masayuki; Hiraga, Mitsutaka; Hirosawa, Kenji; Funada, Masao; Yamamoto, Minoru
Japan, Turkey, Belgium, Spain, Hungary, United States, Ukraine, Slovakia, Russia, United Kingdom, France, Germany, Malta
Abstract
We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at the Okayama Observatory of Kyoto University and through the Variable Star Network collaboration (VSNET). Our spectroscopic observations for six outbursts were performed within 1 d of their optical peak. 11 objects (TCP J00590972+3438357, ASASSN-19ado, TCP J06073081-0101501, ZTF20aavnpug, ASASSN-19ady, MASTER OT J061642.05+435617.9, TCP J20034647+1335125, ASASSN-20kv, ASASSN-20kw, MASTER OT J213908.79+161240.2, and ASASSN-20mf) were previously unknown systems, and our observations enabled quick classification of their transient type. These results illustrate that the Seimei telescope has the capability to conduct quick follow-up observations of unknown transients. Our photometric observations yielded that 11 of the objects are WZ Sge-type dwarf novae and their candidates, and the other six are SU UMa-type dwarf novae and their candidates. The He II 4686 Å emission line was clearly detected among ASASSN-19ado, TCP J06073081-0101501 and MASTER OT J213908.79+161240.2, the association of which with a spiral arm structure in an accretion disk has been suggested in previous studies. Our result suggests that a higher-inclination system shows a stronger emission line of He II 4686 Å, as well as larger-amplitude early superhumps.