Red Giants of Population II. III.

The question whether the helium flash causes mixing of hydrogen into the helium core is examin' computing detailed model sequences for three stars differing in mass and composition. These sequ derived by the Henyey method, cover the entire helium-flash phases. The numerical results indicatc the convective core, though greatly extended during the later cooling phases after the helium misses reaching the hydrogen-rich layers, but only by a very narrow margin. In view of the narro of this margin and because of the fact that a number of physical complications have not yet been 1 into account in these computations, we still cannot answer the question regarding mixing caused b helium fla .