Diffuse interstellar band

Diffuse interstellar bands (DIBs) are absorption features seen in the spectra of astronomical objects in the Milky Way and other galaxies. They are caused by the absorption of light by the interstellar medium. Circa 500 bands have now been seen, in ultraviolet, visible and infrared wavelengths.Much astronomical work relies on the study of spectra - the light from astronomical objects dispersed using a prism or, more usually, a diffraction grating. A typical stellar spectrum will consist of a continuum, containing absorption lines, each of which is attributed to a particular atomic energy level transition in the atmosphere of the star.The great problem with DIBs, apparent from the earliest observations, was that their central wavelengths did not correspond with any known spectral lines of any ion or molecule, and so the material which was responsible for the absorption could not be identified. A large number of theories were advanced as the number of known DIBs grew, and determining the nature of the absorbing material (the 'carrier') became a crucial problem in astrophysics.The first prediction that C60+ could be a carrier of DIBs was put forward by Harry Kroto, co-discoverer of C60. In 1987, Kroto proposed that 'The present observations indicate that C60 might survive in the general medium (probably as the ion C60+) protected by its unique ability to survive processes so drastic that most, if not all, other known molecules are destroyed.' However, that time it was hard to prove due to inability to record a reliable spectrum of C60+.