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| Paper: |
Mass Transfer/Loss from AGB Stars in Close Binaries |
| Volume: |
199, Asymmetrical Planetary Nebulae II: From Origins to Microstructures |
| Page: |
107 |
| Authors: |
Iben, Icko, Jr. |
| Abstract: |
It is argued that, in a close binary system, when the donor is a thermally pulsing asymptotic giant branch (TPAGB) star with a well developed ``dusty wind'', most of the matter lost by the TPAGB star is blown out of the system, and mass transfer to the companion is by accretion from the wind of the donor. Even if the TPAGB star fills its Roche lobe, the tendency towards orbital contraction due to the loss of orbital angular momentum by the ``egg beater'' interaction of the orbiting stars with circumstellar matter is offset by the tendency toward expansion due to wind mass loss from the system. In short, the common envelope (CE) scenario which accounts for the existence of short period evolved binaries such as cataclysmic variables and low mass X-ray binaries may not operate when the donor is a TPAGB star. This inference complements an earlier study which suggests that, in known planetary nebulae with close binary central stars, the properties of the central star can best be understood if the precursor of the helium star or white dwarf component filled its Roche lobe as an early asymptotic giant branch (EAGB) star before a strong dusty wind had a chance to develop (Iben & Tutukov 1993). In the following, five concrete examples serve to develop these points. |
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