|  | 
	
		|  |  
		| Paper: | Molecules in the envelopes of old stars |  
		| Volume: | 9, Cool Stars, Stellar Systems, and the Sun: Sixth Cambridge Workshop |  
		| Page: | 429 |  
		| Authors: | Lucas, R. |  
		| Abstract: | Recent advances in radio observations of molecules in circumstellar envelopes are discussed. These include the detection of new molecular species in IRC + 10216 (SiC, SiC4); the discovery of strong masing lines from HCN; determinations of molecular abundances, including those of sulfur-bearing and carbon-bearing species in oxygen-rich stars; measurements of isotopic ratios of carbon, sulfur, silicon, nitrogen, and CO; and observations of particular objects such as young planetary and protoplanetary nebulae. |  
		|  |  
		|  |  |  |