The evolution during the core hydrogen burning stage of close binary systems with total masses in the range1.37 to 2.25 M? is investigated. The initial separation is chosen so that after the mass loss on a thermal time scale caused by the primary expanding to fill its inner critical Roche surface a system with a common convective envelope is obtained. This common envelope was constructed according to the model proposed by Lucy. The subsequent evolution of the contact system is followed until contact is broken or hydrogen is exhausted at the centre of the primary. Such systems would be identified as W Ursae Majoris systems, but it is pointed out that all W UMa systems cannot arise in this manner.
- 1 - natural sciences ; 2 - physics & astronomy ; 3 - astronomy & astrophysics
- 1 - sciences appliquees, technologies et medecines ; 2 - sciences biologiques et medicales ; 3 - sciences biologiques fondamentales et appliquees. psychologie ; 4 - genetique des eucaryotes. evolution biologique et moleculaire
- 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
- 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Astronomy and Astrophysics