Diffuse interstellar bands
What molecules cause the hundreds of unexplained absorption lines (diffuse interstellar bands) seen in starlight passing through interstellar space, and why have only a handful been identified after a century of study?
History and references
Partly settled. Some of it is understood, some is still argued about.
Discovered in the 1920s, diffuse interstellar bands are a set of hundreds of absorption features in starlight that don't match any known atomic or simple molecular transitions. In 2015, laboratory spectroscopy in a cold ion trap matched the buckminsterfullerene cation (C60+) to two (later four) specific near-infrared bands, the first firm identification since their discovery nearly a century earlier. The overwhelming majority of the roughly 500 known bands still have no confirmed carrier molecule, so the broader puzzle remains only partially solved.
Starlight traveling for millennia carries a fingerprint of interstellar chemistry that took a hundred years and a soccer-ball-shaped carbon molecule to begin decoding.
Explanations that circulated
- That all ~500 known diffuse interstellar bands are now explained — only a small number (a handful of C60+ bands) have been confirmed; the vast majority of DIBs still have no confirmed carrier
References
- Laboratory confirmation of C60+ as the carrier of two diffuse interstellar bands, E. K. Campbell, M. Holz, D. Gerlich, J. P. Maier, Nature, 2015
Solutions 0
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