Even the octatetraynyl radical in its 2Π3/2 lower
spin component has been detected in ten rotational transitions toward
IRC +10216 by
J. Cernicharo, and M. Guélin,
Discovery of the C8H Radical,
Astron. Astrophys. 309 L27L30 (1996)
before it was actually detected in the laboratory.
Later, it was also identified in TMC-1 by observing four lines of two
M. B. Bell, P. A. Feldman, J. K. G. Watson, M. C. McCarthy, M. J. Travers, C. A. Gottlieb, and P. Thaddeus,
Observations of Long CnH Molecules in the Dust Cloud TMC-1,
Astrophys. J. 518 740747 (1999).