Discovery of a Probable Nova in M81

ATel #16248; K. Hornoch (Ondrejov), H. Kucakova (Charles University), S. C. Williams (Turku), G. Sala, J. Jose (UPC-IEEC), B. Stecklum (TLS), M. J. Darnley (LJMU), A. Kaur (PSU), D. H. Hartmann (Clemson), A. W. Shafter (SDSU)
on 20 Sep 2023; 19:14 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)

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The M81 nova monitoring collaboration reports the discovery of a probable nova in M81 on a co-added 5400-s unfiltered CCD frame taken on 2023 Sep. 20.115 UT with the 0.65-m telescope at Ondrejov.

The object designated PNV J09553325+6903128 is located at R.A. = 9h55m33s.25, Decl. = +69o03'12".8 (equinox 2000.0), which is 0.4" east and 42.3" south of the center of M81 (see link to discovery image below).

Here we list the observing dates and corresponding photometry:

 
  Date [UT]    |  Mag   | Err  | Filter  | Telescope 
 
2023-09-16.111 | <20.6  |      | C       | OND  
2023-09-17.091 | <19.7  |      | C       | OND  
2023-09-20.115 |  19.5  | 0.2  | C       | OND  
 

As with all extragalactic novae, follow-up spectroscopic and photometric observations to determine the nova's spectroscopic class and rate of decline (speed class) are encouraged.

The OND 0.65-m is a reflecting telescope at the Ondrejov observatory operated jointly by the Astronomical Institute of ASCR and the Astronomical Institute of the Charles University of Prague, Czech Republic. It uses a Moravian Instruments G2-3200 MkII CCD camera (with a Kodak KAF-3200ME sensor and standard BVRI photometric filters) mounted at the prime focus. The unfiltered OND photometry was calibrated against R-band comparison stars from Perelmuter & Racine (1995).

Discovery image