ИСТИНА

Red novae are the new class of variable stars turning into cool supergiants during their outbursts. In the explosions, red novae have a definitely red color, K-M spectra of supergiants, evolving to more and more later spectral subclass, and they don't pass a nebular phase characteristic of classical novae. Great interest to red novae is attracted by the assumption of their origin as a result of merging in close binary systems. Theorists consider that about 10 percent of binary systems have to pass a merging stage. For the first time it was succeeded to observe merging process of components in a contact binary system in case of the research of the Nova Sco 2008 (V1309 Sco) pre-explosion condition. In the report, we will provide photometric and spectral observations of several red novae at the BTA. First of all, we present results of our researches of the unique red novae V838 Mon. Many researchers consider it as a prototype of this class of astrophysical objects. Its outburst happened in January 2002, and it was the brightest star by absolute magnitude in the Galaxy. After the outburst for a short time V838 Mon became a unique "brown" supergiant with a temperature of 1200 K. This wide binary system is connected to the cluster of B-type stars and a dust nebula, in which the unique and most beautiful light echo was extending within several years after the outburst. In 2008 a unique phenomenon for astrophysics was observed: the hot component of the system which remained after the outburst was engulfed by a cool remnant of explosion. During 8 years it has not appeared. The future of V838 Mon is unpredictable. The results of researches of two red novae in the near galaxies M31 and M101 performed at the BTA will be presented. Photometric and spectroscopic investigations of an uncommon object found in a phase of a supernova impostor will be shown. Then in a month, it broke out as a real supernova and was interpreted by us as a collapse of a massive star core in the process of its merging with a component in a binary system (a failed luminous red nova).