, and the
stars are notoriously not members of that sequence.[189] Cyanogen is also a typical constituent of the comet-head spectrum.[190][191][192]
Carbon Oxides. The band spectrum attributed to the CO molecule,[193][194] is a strong feature of the spectra of
and
stars.[195][196] It is also the chief component of the spectrum of the comet tail, which has been reproduced in the laboratory, at very low pressures, by A. Fowler.[197]