Dense cores in dark clouds. IV. HC/sub 5/N observations

Journal Article · Fri Jul 15 04:00:00 EDT 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161151· OSTI ID:5599878

Benson, P J; Myers, P C

We report detections or possible detections of the J = 9-8 rotational transition of HC/sub 5/N in 10 new dark cloud sources. All of the strong sources and most of the known sources are in Taurus. In contrast to maps of TMC-1, maps of NH/sub 3/ and HC/sub 5/N emission in L1544 and in TMC-1C show no relative shift of peak positions. Column densities of HC/sub 5/N and C/sup 18/O are roughly correlated, but N(HC/sub 5/N) increases faster than N(C/sup 18/O), suggesting that the abundance of HC/sub 5/N ranges from approx.10/sup -10/ in the weakest sources to approx.10/sup -9/ in the strongest sources. Comparison with predictions of chemical models indicates that this abundance variation is unlikely to be due to variations in cloud density, but it may be due to differences in the degree of chemical evolution from cloud to cloud. If so, TMC-1 is more evolved than L183.

• Research Organization: Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, and Amelia Earhart Fellow
• OSTI ID: 5599878
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 270:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

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640105* -- Astrophysics & Cosmology-- Galaxies
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ENERGY-LEVEL TRANSITIONS
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