Evolution of Close Binaries

Most stars of our Galaxy's disk are double. The existing estimation of duplicity ααrange from ~ 50-70 % (Abt, Levy, 1976, Abt, 1979) to ~ 100 % (Kraitcheva et al., 1978). About half of all stars are close binaries (CB) and hence their components fill their Roche lobes during evolution. This accounts for the constantly increasing interest to their evolution. Several review papers were published in the last years: Paczynski (1971), Tutukov et al. (1975), van den Heuvel (1976), Massevitch et al. (1976), Thomas (1977), Paczynski (1979), Webbink (1979b), Yungelson and Massevitch (1980). The subject matter of close binary evolution is very wide now, therefore, I will limit myself to the review of modern scenarios for evolution of massive (M ≳ 10 M⊙) close binaries (MCBS) and close binaries of moderate (M ≲ 10 M⊙) mass.