The January 2015 outburst of a red nova in M 31 A. A. Kurtenkov, P. Pessev, T. Tomov, E. A. Barsukova, S. Fabrika, K. Vida, K. Hornoch, E. P. Ovcharov, V. P. Goranskij, A. F. Valeev et al. (12 more) A&A, 578 (2015) L10 Published online: 15 June 2015 DOI: 10.1051/0004-6361/201526564