ON THE GAS HEATING IN STELLAR FLARES - THE HEATING BY ELECTRONS

As well as in our previous paper, we adopt that at the beginning of a flare an explosion takes place in the stellar surface layers, which ge nerates high-energy particles. Penetrating to deeper layers, these par ticles heat them, causing an optical flare. In the previous paper, the problem of the atmospheric heating by protons was considered; In this paper - that by electrons. The temperature distribution in the flare region is found as the function of total energy flux of electrons F0 a nd the energy cutoff E1. It makes possible to determine theoretical co lour indices of outgoing radiation U - B, B - V, V - R and V - I, and their dependence on the parametes F0 and E1 and on the place at the st ar disc. For the case of electron heating, the U - B, B - V is the sam e, as for proton heating, but for other values of F0 and E1. Compariso n of theoretical values of U - B, B - V, Y - R with the observed ones for the strong flares of EV Lac has shown that the colour indices are close to each other for F0 almost-equal-to 3.10(11) erg /cm2.s, E1 alm ost-equal-to 100 keV, and when the flare is on the periphery of the di sc. The problem of the atmospheric heating with indicence of borth pro tons and electrons is also discussed. In the last part, the heating fu nction is determined with an account for relation between the particle energt and velocity, and it makes clear the role of relativistic elec trons in the atmospheric heating.