Discovery of a Possible Symbiotic Nova in M31, M31N 2022-10c
ATel #17810; K. Hornoch (Ondrejov), A. W. Shafter (SDSU), M. Myslivec (HVBO, Czech Republic), H. Kucakova (Ondrejov)
on 22 May 2026; 18:49 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)
Subjects: Optical, Nova, Transient
We report the discovery of a possible symbiotic nova in M31 on a co-added 3600-s R-band CCD frame taken on 2022 Oct. 26.135 UT with the 40-in reflector at SDSU's Mount Laguna Observatory (MLO). The nova was discovered during our recent search of archival MLO data for presence of potential faint and fast novae.
Subsequently, we found many prediscovery (back to 2020) and recent detections of the object using our archival images taken with variety of telescopes as well as our recent images taken during our ongoing nova survey of the central region of M31.
The object was designated as M31N 2022-10c = PNV J00425120+4116594 and is located at R.A. = 0h42m51s.20, Decl. = +41o16'59".4 (equinox 2000.0), which is 35.2" east and 50.0" north of the center of M31 (see link to discovery and comparison image below).
The following magnitudes demonstrate its very slow photometric evolution and recent brightening in Hα resulting in strong Hα excess typical for novae:
Date [UT] | Mag | Err | Filter | Telescope
2001-09-20.349 | >21.0 | | R | 4-m KPNO
2005-06-11.802 | >20.6 | | Hα | 2.54-m INT*
2006-09-18.340 | >20.8 | | R | 3.5-m WIYN
2013-08-14.002 | >21.0 | | R | 1.23-m CAHA
2018-12-15.000 | >20.7 | | R | 1.54-m Danish
2019-11-28.017 | >20.8 | | R | 1.54-m Danish*
2020-11-06.001 | 19.7 | 0.2 | R | 1.54-m Danish
2020-11-15.997 | 19.5 | 0.2 | R | 1.54-m Danish
2021-11-30.016 | 19.6 | 0.25 | R | 1.54-m Danish
2021-12-22.772 | 18.9 | 0.2 | Hα | 0.4-m HVBO
2022-06-26.984 | 19.2 | 0.25 | R | 0.65-m Ondrejov
2022-10-26.135 | 19.3 | 0.1 | R | 1-m MLO*
2022-11-21.014 | 19.1 | 0.15 | R | 1.54-m Danish
2023-12-29.098 | 19.8 | 0.1 | B | 1-m MLO
2023-12-29.123 | 19.5 | 0.1 | V | 1-m MLO
2023-12-29.147 | 19.1 | 0.1 | R | 1-m MLO
2026-04-30.061 | 17.3 | 0.2 | Hα | 0.4-m HVBO
2026-05-02.091 | 19.5 | 0.25 | R | 0.65-m Ondrejov
2026-05-10.030 | 16.8 | 0.1 | Hα | 0.4-m HVBO
2026-05-18.062 | 16.6 | 0.1 | Hα | 0.4-m HVBO*
Asterisks in the Telescope column identify images used in the discovery and comparison image.
Despite its proximity to the bright M31 center, we strongly encourage follow-up spectroscopic and photometric observations to firmly classify the object. This work is based (in part) on data collected with the Danish 1.54-m telescope at the ESO La Silla Observatory.
Discovery and comparison image: top left pre-outburst R-band; top right discovery R-band; bottom left pre-outburst H_alpha; bottom right in outburst H_alpha
