Discovery of a Probable Nova in M31, M31N 2026-04b
ATel #17762; K. Hornoch (Ondrejov), M. Myslivec (HVBO, Czech Republic), A. W. Shafter (SDSU)
on 23 Apr 2026; 21:13 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 probable nova in M31 on a co-added 4200-s H_alpha CMOS frame taken on 2026 Apr. 23.056 UT with the 0.4-m telescope at Belec nad Orlici. The M31 nova was observed at very low elevation under poor seeing conditions. There is nothing visible at the position of the object down to H_alpha = 19.6 mag on a high-quality image taken on 2021 Dec. 22.772 UT with the same instrumentation.
The object was designated as M31N 2026-04b = PNV J00433502+4146280 and is located at R.A. = 0h43m35s.02, Decl. = +41o46'28".0 (equinox 2000.0), which is 569.3" east and 1819.5" north of the center of M31 (see link to discovery image below).
The following H_alpha magnitudes were obtained using the 0.4-m telescope (HVBO):
Date [UT] | Mag | Err | Filter | Telescope
2021-12-22.772 | >19.6 | | Ha | HVBO
2026-04-10.095 | >18.8 | | Ha | HVBO
2026-04-23.056 | 15.9 | 0.2 | Ha | HVBO
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
