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		| Paper: | 
		Duplicity: Its Part in the AGB's Downfall | 
	 
	
		| Volume: | 
		497, Why Galaxies Care about AGB Stars III: A Closer Look in Space and Time | 
	 
	
		| Page: | 
		161 | 
	 
	
		| Authors: | 
		Izzard, R. G.; Keller, D. | 
	 
	
	
		| Abstract: | 
		Half or more of stars more massive than our Sun are orbited by a  companion star in a binary system. Many binaries have short enough  orbits that the evolution of both stars is greatly altered by an  exchange of mass and angular momentum between the stars. Such mass  transfer is highly likely on the asymptotic giant branch (AGB)  because this is when a star is both very large and has strong wind  mass loss. Direct mass transfer truncates the AGB, and its associated  nucleosynthesis, prematurely compared to the case of a single star. In  wide binaries we can probe nucleosynthesis in the long-dead AGB primary  star by today observing its initially lower-mass companion. The  star we see now may be polluted by ejecta from the primary either  through a wind or Roche-lobe overflow. We highlight recent  quantitative work on nucleosynthesis in (ex-)AGB mass-transfer  systems, such as carbon and barium stars, and the link between binary  stars and planetary nebulae; finally, we suggest AGB stars as a  possible source of the enigmatic element, lithium. | 
	 
	
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