Tomo-e Gozen Discovered a Large-Amplitude CV
ATel #17912; Taiga Sasaoka (the University of Tokyo), Kenta Taguchi, Keisuke Isogai (Kyoto University)
on 20 Jul 2026; 15:32 UT
Credential Certification: Keisuke Isogai (isogai@kusastro.kyoto-u.ac.jp)
Subjects: Optical, Cataclysmic Variable, Transient, Variables
We discovered a large-amplitude CV, TCP J20354364+6131329, in Cepheus at 14.41 ± 0.02 mag on 2026-07-20.5443 UT (unfiltered) by the Tomo-e Gozen transient survey (Sako et al. 2018) on the Kiso Schmidt telescope, the University of Tokyo.
The coordinates are (20:35:43.64, +61:31:32.91) in J2000.
This CV candidate is also confirmed by the TriCCS Camera on the 3.8-m telescope Seimei (Kurita et al. 2020) at Okayama Observatory of Kyoto University.
There is a possible counterpart of g = 21.92, r = 21.72, and i = 21.53 in the Pan-STARRS DR2.
We obtained a spectrum by using a fiber-fed integral field spectrograph (KOOLS-IFU; Matsubayashi et al. 2025) on the Seimei telescope on 2026-07-20.5778 UT.
Since the quick look spectrum shows a blue continuum with the Balmer lines. Hα is an emission line, and Hβ is an absorption line with a possible central emission core, we classify this object as a large-amplitude CV (possibly WZ Sge-type dwarf nova).
Following-up observations are encouraged.
