AT 2026xf (M31N 2026-01b) is a Recurrence of the Newly-Identified Recurrent Nova M31N 2008-01a
ATel #17604; Kenta Taguchi (Kyoto University), Jingyuan Zhao, Yaozhang Ou, Bozhang Shi, Haoyun Yang, Chunpeng Bi, Jianlin Xu, Mi Zhang, Hualin Li, Yanxi Li, Ziyang Mai, Leiming Tang, Wenjie Zhou, Guoyou Sun, Jiangao Ruan, Xing Gao (Xingming Observatory), K. Hornoch (Ondrejov, Czech Republic), R. Fidrich, T. Tordai (HAA/VSS), A. W. Shafter (SDSU)
on 15 Jan 2026; 19:50 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)
Subjects: Optical, Nova, Transient
The M31 nova candidate AT 2026xf (aka M31N 2026-01b; PNV J00425852+4114442;
PSP26C; Vend82) was discovered through a citizen science program called the
Popular Supernova Project (PSP).
A quick-look spectrum taken on 2026 Jan. 14.41 UT taken with
the fiber-fed integral field spectrograph (KOOLS-IFU; Matsubayashi et al. 2025)
mounted on the 3.8 m Seimei telescope (Kurita et al. 2020)
at Okayama Observatory of Kyoto University shows a broad
(~ 2700 km/s) Hα line consistent with that expected for a nova.
The position of the nova led us to suspect that AT 2026xf
(hereafter M31N 2026-01b) was a likely recurrence of the known
M31 nova M31N 2008-01a.
A precise registration of the co-added 150-sec g+r+i image obtained on
2026 Jan. 14.406 UT using the Tricolor CMOS Camera and Spectrograph
(TriCCS)
on the 3.8-m Seimei Telescope with a discovery image of M31N 2008-01a
taken by Burwitz et al. with the 0.6-m Super-LOTIS telescope (ATel #1364)
demonstrates that the novae are spatially coincident to better than 1"
(see the link to the comparison image below).
The probability of a chance positional coincidence of two unrelated novae at their observed positions is p=0.003. We conclude that M31N 2026-01b is the second reported eruption of the newly-recognized recurrent nova M31N 2008-01a. This discovery brings the total number of RN known in M31 to 23 systems.
Additional photometric observations to better characterize the light curve of M31N 2026-01b are in progress.
Comparison image: M31N 2008-01a is black, M31N 2026-01b is white
