Abstract
The HCN J = 1-0 transition in bipolar reflection nebulae (BRN), planetary nebulae (PN) and OH/IR sources was investigated with 14-m mm-wave radiotelescope data operating at 88.6 GHz. The scans covered the stellar objects CRL 618, OH 231.8 + 4.2, CRL 2688, IK Tau, NGC 7027, Chi Cyg and CRL 2135. Data from other sources identified by previous researchers were included in the analyses. The HCN line profiles of BRN exhibited broad and narrow velocity features, which indicated that HCN was present in both the bipolar flow and the disk around the IR soruce. An abundance ratio of HCN/H2 or 1/10 million to 1/100 million was calculated for circumstellar envelopes. The outer circumstellar envelopes of both oxygen-rich and carbon-rich stars emitted spectra from complex photochemical interactions. Significant physical similarities were found between the gas of BRN and around PN. Finally, data on SiO J = 3-1, v = 0 transitions observed in various OH/IR stars ae also reported. 49 references
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