Effects of binarity on asymptotic giant branch evolution

Abstract. Binarity can have a significant effect on the evolution and nucleosynthesis in a substantial fraction of all AGB stars. In this contribution I discuss the evidence for binary interaction among AGB stars and their progeny, and I provide an overview of the various binary interaction processes that play a role in AGB binaries and discuss their uncertainties. Key words. AGB stars – binaries – stellar evolution 1. AGB stars in binaries The majority of stars occur in binary or higher-order multiple systems (Abt 1983), and this must also be true of AGB stars although it is harder to prove directly than for dwarfs or nor-mal giants. A significant fraction of these bi-naries are expected to interact during the AGB phase in one way or another. This interaction can strongly affect the properties, the further evolution and the nucleosynthesis of the AG