An Etymological Dictionary of Astronomy and Astrophysics
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1) A colorless, very poisonous, flammable gas with a smell of bitter almonds. Chemical formula: C₂N₂. It was discovered by Louis Joseph Gay-Lussac (1778-1850) in 1848.
2) A univalent radical, CN, found in simple and complex cyanide compounds. CN exists in → interstellar medium and is one of the main molecules detected in → comets. It has energy levels at 113 and 227 GHz (2.6 and 1.3 mm wavelength) above the ground level.

→ cyano- + → -gen.

An → absorption band of molecular origin characterizing the spectra of → late-type stars (G0 and later, e.g. → S star). → Cyanogen absorption is an important → luminosity criterion for → low-mass stars, and is more pronounced in → giant stars than in → dwarf stars of the same → spectral type.

→ cyanogen; → band.