Discovery of a Probable Nova in M31, M31N 2025-12d
ATel #17545; K. Hornoch (Ondrejov), H. Kucakova (Charles University), A. W. Shafter (SDSU)
on 16 Dec 2025; 18:43 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 17550
We report the discovery of a probable nova found during our survey of the central region of M31. The object was discovered on a co-added 360-s R-band CCD frame taken on 2025 Dec. 16.025 UT with the Danish 1.54-m telescope at La Silla Observatory.
The object was designated as M31N 2025-12d = PNV J00422038+4114207 and is located at R.A. = 0h42m20s.38, Decl. = +41o14'20".7 (equinox 2000.0), which is 270.0" west and 107.8" south of the center of M31 (see link to discovery image below).
The following R-band magnitudes were obtained using the Danish 1.54-m telescope (DK154):
Date [UT] | Mag | Err | Filter | Telescope
2025-12-15.023 | >19.5 | | R | DK154
2025-12-16.025 | 18.07 | 0.07 | R | DK154
As with all extragalactic novae, follow-up spectroscopic and photometric observations to confirm the nova's nature and determine its spectroscopic class and rate of decline (speed class) are encouraged.
Discovery image
