Spectroscopic classification of the ultra-short period dwarf nova MASTER OT J234843.23+250250.4
Keisuke Isogai, Miho Kawabata (Kyoto University, Okayama Observatory), Keiichi Maeda (Kyoto University)
We report on a low-resolution spectrum of the ultra-short period dwarf nova MASTER OT J234843.23+250250.4. The previous superoutburst of this object was detected in 2013, then Kato et al. (2014) reported that the superhump period is only 0.034 d. Thus, this object had been a good candidate for an AM CVn-type (helium-rich) object. According to the report by Patrick Schmeer , the present outburst has started on Nov. 1. We obtained a low-resolution spectrum on 2019-11-05.62 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. The spectrum shows a blue continuum with Hβ and γ absorption lines. On the other hand, there are no definite signals of helium lines. Thus, we concluded that this object is an EI Psc-type object, which is a hydrogen-rich dwarf nova below the period minimum, rather than an AM CVn-type one.
optical,cataclysmic variable,nova,transient,variables