Independent Discovery of a Probable Nova in M31
ATel #17910; A. Valcheva (Sofia University, Bulgaria), A. Kostov (IANAO, BAS, Bulgaria), V. Kozhuharov
on 20 Jul 2026; 11:54 UT
Credential Certification: Antoniya Valcheva (valcheva@phys.uni-sofia.bg)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 17914
We report independent discovery of a probable nova in M31 (designated M31N 2026-07a) on R-band CCD images taken on 2026 July 19.9993 UT with the 50/70 Schmidt telescope at Rozhen NAO, Bulgaria. (Discovery images can be found here). The object is located at RA=0h42m55s.930, DEC=+41o17'31".19 (equinox 2000.0), which is 130.9'' east and 82.7'' north of the center of M31. The transient is also detected at a faint magnitude on our prediscovery images taken with the same equipment on 2026 July 18.9676 UT.
The transient was independently discovered on 2026 July 20.01:57:04.320 UT by Robert Fidrich and Tamas Tordai (HAA/VSS) and is designated as AT 2026vdo.
BR-band magnitudes are summarized below:
2026 July 18.9676 UT R=19.0± 0.2 mag; 3x300 sec
2026 July 18.9789 UT B=19.3± 0.2 mag; 3x300 sec
2026 July 19.9993 UT R=17.90± 0.10 mag; 3x300 sec
2026 July 20.0014 UT B=18.36± 0.08 mag; 3x300 sec
Follow-up photometric and spectroscopic observations are recommended to classify the transient and determine its speed class.
This study is supported by the National RI Roadmap Project D01-109/30.06.2025 with the Ministry of Education and Science of the Republic of Bulgaria.
