The octatetraynyl radical (C8H) was detected by
Cernicharo and Guélin in 1996 and
published back-to-back with new experimental data on the molecule measured by
McCarthy et al.
(where the species was generated by spark discharge of acetylene). C8H was detected toward
IRC +10216 like many other highly unsaturated
hydrocarbon species. 10 rotational transitions were matched to unknown features in two surveys of the source, one
performed with the IRAM
30m telescope and other with the
45m telescope at Nobeyama by
Kawaguchi et al.
The column density of C8H was
refined in 2007 with observations of the
100m telescope in Green Bank.