Fullerene C₆₀ identified in the Milky Way

Lick Observatory astronomer Mary Lea Heger first observed what were to be called 'diffuse interstellar bands' in 1919. These are absorption lines seen towards reddened stars, and although hundreds are now known, until now none of the molecules giving rise to them have been conclusively identified. In 1994, Bernard Foing and Pascale Ehrenfreund reported two diffuse interstellar bands with wavelengths close to those of the absorption bands of fullerene C₆₀⁺ measured in a neon matrix. A more certain identification awaited the gas-phase spectrum of C₆₀⁺. John P. Maier and colleagues now present laboratory measurements of the gas-phase spectrum of C₆₀⁺ and confirm that the diffuse interstellar bands that Foing and Ehrenfreund observed do arise from C₆₀⁺. As C₆₀ has already been detected in various nebulae by detection of its infrared spectrum, this new observation in the Milky Way can only add to current interest in the role of astronomical fullerenes.