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		| Paper: | Transition from red giant to planetary nebula |  
		| Volume: | 9, Cool Stars, Stellar Systems, and the Sun: Sixth Cambridge Workshop |  
		| Page: | 438 |  
		| Authors: | Kwok, Sun |  
		| Abstract: | Spectroscopic and photometric data from IRAS survey are presented showing that the evolution from asymptotic giant branch (AGB) to planetary nebulae (PNs) can be traced in a continuous IR sequence. This sequence demonstrates that the circumstellar envelope ejected during an AGB star can still be observed in a PN, suggesting that such material must have played a dominant role in the formation of PNs. This link between AGB and PNs can be used to predict the properties of proto-PNs. A summary of the observational stages between AGB stars and PNs is presented. |  
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