On the Detection of Cyanooctatetrayne, HC9N, in Space

N. W. Broten, T. Oka, L. W. Avery, J. M. MacLeod, and H. W. Kroto,
The Detection of HC9N in Interstellar Space
Astrophys. J. 223, L105–L107 (1978)
reported the first detection of this cyanopolyyne in two transitions (J = 18 – 17 and 25 – 24 near 10.5 and 14.5 GHz, respectively) in Heile's Cloud 2 employing the 46 m radio telecope of the Algonquin Radio Observatory before the molecules was detected in the laboratory. The spectroscopic parameters were estimated from the smaller cyanopolyynes. Heile's Cloud 2 is better known as TMC-1.

More recently, the molecule was also detected in six transitions in the circumstellar shell of the famous carbon star CW Leo:
M. B. Bell, L. W. Avery, J. M. MacLeod, and H. E. Matthews,
The Excitation Temperature of HC9N in the Circumstellar Envelope of IRC +10216
Astrophys. J. 400, 551–555 (1992).

Truong-Bach, D. Graham, and Nguyen-Q-Rieu,
HC9N from the Envelopes of IRC +10216 and CRL 2688
Astron. Astrophys. 277, 133–138 (1993);
detected one additional higher-J transition toward the former source and the same transition in a protoplanetary nebula.

Contributor(s): H. S. P. Müller; 02, 2006; 06, 2009.