Spectroscopic identification of the bright transient TCP J20034647+1335125 as a dwarf nova
ATel #13947; Kenta Taguchi, Naoto Kojiguchi, Yusuke Tampo, Shumpei Nagoshi (Kyoto University), Keisuke Isogai, Masaaki Otsuka (Kyoto University)
on 15 Aug 2020; 20:11 UT
Credential Certification: Keisuke Isogai (isogai@kusastro.kyoto-u.ac.jp)
Subjects: Optical, Cataclysmic Variable, Transient
We report on a spectrum of the bright optical transient TCP J20034647+1335125.
We obtained the spectrum on 2020-08-15.7 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.
As reported to CBAT, this object was discovered by Hideo Nishimura at 12.6 mag on 2020-8-15.504 UT. There is an SDSS counterpart (u=21.4, g=21.36, r=21.51, i=21.5) and GALEX one (FUV=21.2, NUV=21.9) (vsnet-alert 24541, 24542).
Our spectra show a blue continuum with Balmer and He I absorption lines. These features suggest that this object is a dwarf nova in outburst.
We also performed time-series photometry in 2020-08-15.68--75 UT by using Kyoto University 40-cm telescope.
Although the spectra and the large outburst amplitude of ~8.5 mag suggest that this object is a WZ Sge-type dwarf nova, there is no clear signal of superhumps.
Thus, the inclination of this object is not high or early superhumps have not been fully grown yet.
Spectrum