The January 2015 outburst of a red nova in M 31

Kurtenkov, A. A.; Pessev, P.; Tomov, T.; Barsukova, E. A.; Fabrika, S.; Vida, K.; Hornoch, K.; Ovcharov, E. P.; Goranskij, V. P.; Valeev, A. F.; Molnár, L.; Sárneczky, K.; Kostov, A.; Nedialkov, P.; Valenti, S.; Geier, S.; Wiersema, K.; Henze, M.; Shafter, A. W.; Muñoz Dimitrova, R. V.; Popov, V. N.; Stritzinger, M.
Referencia bibliográfica

Astronomy and Astrophysics, Volume 578, id.L10, 5 pp.

Fecha de publicación:
6
2015
Número de autores
22
Número de autores del IAC
2
Número de citas
32
Número de citas referidas
30
Descripción
Context. M31N 2015-01a (or M31LRN 2015) is a red nova that erupted in January 2015 - the first event of this kind observed in M 31 since 1988. Very few similar events have been confirmed as of 2015. Most of them are considered to be products of stellar mergers. Aims: Results of an extensive optical monitoring of the transient in the period January-March 2015 are presented. Methods: Eight optical telescopes were used for imaging. Spectra were obtained on the Large Altazimuth Telescope (BTA), the Gran Telecsopio Canarias (GTC) and the Rozhen 2 m telescope. Results: We present a highly accurate 70 d light curve and astrometry with a 0.05''uncertainty. The colour indices reached a minimum of 2-3 d before peak brightness and rapidly increased afterwards. The spectral type changed from F5I to F0I in 6 d before the maximum and then to K3I in the next 30 d. The luminosity of the transient was estimated to be 8.7+3.3-2.2 × 105 L⊙ during the optical maximum. Conclusions: Both the photometric and the spectroscopic results confirm that the object is a red nova, similar to V838 Monocerotis. Table 4 is available in electronic form at http://www.aanda.org