Additional Photometry for nova M31N 2016-12e and classification as a recurrent nova (= M31N 2007-11f)

ATel #10001; P. Sin (UPC-IEEC), M. Henze (CSIC-IEEC), G. Sala (UPC-IEEC), A. Ederoclite (CEFCA), M. Hernanz (CSIC-IEEC), J. Jose (UPC-IEEC), K. Hornoch (Ondrejov), E. Conseil (AFOEV), H. Kucakova (Charles University)
on 25 Jan 2017; 09:35 UT
Credential Certification: Martin Henze (henze@ice.cat)

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We report additional photometry measurements for the recent M31 nova M31N 2016-12e (see ATels #9912, #9942; alternative designations AT2016jbx and MASTER OT J004131.52+410714.2). Sets of four R-band images and one set of two H-alpha images (central wavelength 660nm; FWHM 14.5nm) were obtained in late December 2016 with the JAST/T80 telescope at the Observatorio Astrofisico de Javalambre (OAJ), in Teruel, owned, managed and operated by the Centro de Estudios de Fisica del Cosmos de Aragon. Additional observations were obtained with the 0.65-m telescope at the Ondrejov observatory (OND), operated jointly by the Astronomical Institute of ASCR and the Astronomical Institute of the Charles University of Prague, Czech Republic. Here we list the observing dates and corresponding photometry:

 
Date [UT]      | Mag   | Err  | Filter    | Telescope 
2016-12-26.811 | >20.5 |      | R         | OAJ 
2016-12-27.872 | 16.7  | 0.2  | R         | OAJ 
2016-12-28.831 | 17.6  | 0.3  | R         | OAJ 
2016-12-29.236 | 17.3  | 0.1  | R         | OND 
2016-12-30.224 | 18.0  | 0.1  | R         | OND 
2016-12-30.830 | 18.0  | 0.3  | R         | OAJ 
2016-12-30.841 | 17.2  | 0.3  | Hα        | OAJ 
2017-01-02.181 | 18.4  | 0.2  | R         | OND 
2017-01-06.280 | 18.8  | 0.2  | R         | OND 
2017-01-07.306 | 19.0  | 0.3  | R         | OND 
2017-01-11.204 | 19.1  | 0.3  | R         | OND 
2017-01-16.251 | >20.0 |      | R         | OND 
2017-01-20.225 | >20.9 |      | R         | OND 

In addition, we found that the position of nova M31N 2016-12e was close to that of nova M31N 2007-11f (ATel #1312). Revisiting our archival data from November 2007, we found a clear detection of nova M31N 2007-11f that is spatially consistent with nova M31N 2016-12e. Therefore, we conclude that both eruptions originated from the same binary system and therefore identify M31N 2007-11f as a new recurrent nova (RN) in M31. It is the 18th known RN in M31 (see Shafter et al. 2015 and ATel #7116). In addition to the clear positional match, the location of M31N 2007-11f is relatively far away from the crowded M31 centre, making a chance coincidence of two separate novae very unlikely.

The observed recurrence period of (at least) 9 yr for M31N 2007-11f is similar to that of the RN M31N 1990-10a (ATels #9276, #9280, #9281, #9383, #9386, #9435). Both periods are slightly shorter than in case of the fastest Galactic RN, U Sco (average 10 yr; e.g. Schaefer 2010), but much longer than observed in the record M31 RN M31N 2008-12a (average 0.5 or 1 yr; e.g. ATel #9848 and Darnley et al. 2016, Henze et al. 2015).

The OAJ and OND photometry (including the Hα detection) was calibrated with R band data of the Local Group Galaxies Survey (Massey et al. 2006). We thank the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating the OAJ data used in this work.