ИСТИНА

We discuss briefly new observations of superflares on G main-sequence stars discovered in optics with the Kepler mission. In the framework of a solar flare paradigm, we associate the origin of the strong optical continuum emission with an acceleration of particles of their subsequent impact on dense layers of the chromosphere and the upper photosphere. One of basic problems in gas-dynamical modeling of large flares is knowledge of radiative losses. Using the radiative transfer methods developed by Sobolev and his colleagues, we calculated first a version of the radiative losses for optical thin and thick layers in the L_alpha line. These results applied during more than 35 years, and only now require elaboration of this model. First, we were carried out the new modeling of the previous formulation of the problem for a solar flare applying new algorithm and parallelization with three IZMIRAN computers. We have reproduced those results and realized that conditions in the basic source of the flare optical emission (a low-temperature condensation) are strongly non-equilibrium. We analyze conditions of formation of the hydrogen emission and its features behind the shock front in 2T- approximation with the aim to apply these results in solution of the radiative gas-dynamics equation system. For extreme flares, we discuss problems of limitation of the thermal flux and an influence of the return current as well. We propose a preliminary model of superflares and some consequences.