Independent Discovery of a Probable Nova in M31

ATel #17334; K. Hornoch (Ondrejov), H. Kucakova, K. Honkova (Charles University), A. W. Shafter (SDSU)
on 16 Aug 2025; 00:23 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)

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We report the independent discovery of a probable nova found during our survey of the central region of M31. The object was discovered on a co-added 810-s R-band CCD frame taken on 2025 Aug. 14.813 UT with the 0.65-m telescope at Ondrejov.

The object was independently discovered on Aug. 15.087 UT by R. Fidrich and T. Tordai and designated as AT 2025twt.

The object was designated by us as PNV J00423625+4114431 = M31N 2025-08a and is located at R.A. = 0h42m36s.25, Decl. = +41o14'43".1 (equinox 2000.0), which is 91.0" west and 85.4" south of the center of M31 (see link to discovery image below).

The following R-band magnitudes were obtained using the 0.65-m telescope at Ondrejov (D65):

 
  Date [UT]    |  Mag   | Err  | Filter  | Telescope 
 
2025-08-14.102 | >19.4  |      | R       | D65 
2025-08-14.813 |  18.8  | 0.25 | R       | D65 
 

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