The diffuse interstellar bands

Thomas R. Geballe

Gemini Observatory, USA

The diffuse interstellar bands, or DIBs, are a large set of absorption features, mostly at optical wavelengths, that are seen in the spectra of reddened stars and other objects. They arise in interstellar gas and are observed toward numerous objects in our galaxy as well as in other galaxies. Although long thought to be associated with carbon-bearing molecules, their precise identification has been unknown for nearly a century, as their wavelengths do not coincide with spectral lines of atoms or simple molecules. Very recently, the first believable identifications have been made: several DIBs have been assigned to lines in the spectrum of singly ionized Buckminsterfullerene (C₆₀⁺). This development appears to have begun to solve perhaps the greatest unsolved mysteries in astronomical spectroscopy. In addition, new DIBs have been observed at infrared wavelengths and are the longest wavelength DIBs ever found. I will discuss the characteristics of the DIBs and their history, emphasizing these recent developments.

Last update: