Evolutionary scenarios for intermediate-mass stars in close binaries

摘要: The consequences are explored of assuming that, in common envelope events involving mass transfer close binaries, the energy required to eject from system is comparable with change orbital system. Situations which primary fills its Roche lobe for first time (1) after it has exhausted central hydrogen, but before ignited helium, and (2) already developed an electron-degenerate carbon-oxygen core studied detail. properties a consisting CO degenerate dwarf helium star, angular momentum loss due gravitational wave radiation maintaining star contact, explored. Finally, formation frequency non-Roche filling stars companions various types examined see whether they could account some fraction observed sdB sdO stars. 71 references.