Space buckyballs

The field of nanotechnology is in part rooted in the 1985 Nobel Prize–winning laboratory synthesis of buckyballs—the soccer-ball-shaped carbon molecule, C₆₀—by Rice University chemists Richard Smalley and Robert Curl and their collaborator, University of Sussex chemist Harold Kroto. The synthesis was guided by Kroto’s hypothesis that complex carbon chains could naturally form in the interstellar medium of aging carbon-rich, hydrogen-poor giant branch stars. Now, 25 years later, Jan Cami at the University of Western Ontario and his colleagues have reported the clearest evidence yet of such complex carbon structures in space. The research team analyzed IR spectroscopic data—collected by the Spitzer Space Telescope—of the circumstellar region of a planetary nebula known as Tc 1. As the image shows, the spectrum contains several prominent peaks of C₆₀ (red arrows) and peaks of the rugby-ball-shaped C₇₀ (blue arrows); both molecules were uncharged and in the solid phase. Previous spectra of other carbon-rich planetary nebulae indicated strong emission peaks of volatile polycyclic hydrocarbons, which were completely absent in the monitored region of Tc 1. Cami and his colleagues suggest that the planetary nebula may have ejected its hydrogen envelope a few thousand years ago and that a recent thermal pulse prompted the ejection of the pure carbon dust they’re now observing. (J. Cami et al., Science, in press, doi:10.1126/science.1192035.)—Jermey N. A. Matthews