Washington: Using data from NASA’s Spitzer Space Telescope, an international team of researchers at the Instituto de Astrofísica de Canarias (IAC), Spain, has reported the first extragalactic detection of the C70 fullerene molecule, and the possible detection of “a piece of graphene” in space.
Letizia Stanghellini and Richard Shaw, members of the team at the National Optical Astronomy Observatory in Tucson, Arizona, describe how collisional shocks powered by the winds from old stars in planetary nebulae could be responsible for the formation of fullerenes (C60 and C70) and graphene (planar C24).
Planetary nebulae originate from stars similar to our Sun that have reached the end of their lives and are shedding shells of gas into space.
In this case, the planetary nebulae are located in the Magellanic Clouds, two satellite galaxies to our own Milky Way, that are best seen from the Southern Hemisphere.
At the distance of the Magellanic Clouds, planetary nebulae appear as small fuzzy blobs. However, unlike planetaries in our own Milky Way Galaxy whose distances are very uncertain, the distance to planetaries in the Magellanic Clouds can be determined to better than 5 pc.
With such accurate distances, the researchers determined the true luminosity of the stars and confirmed that the objects are indeed planetary nebulae and not some other object in the astrophysical zoo.
Fullerenes, or Buckyballs, consist of carbon atoms arranged in a three-dimensional sphere similar to the geodesic domes popularized by Buckminster Fuller. The C70 fullerene can be compared with a rugby ball, while C60 is compared to a soccer ball.
Both of these molecules have been detected in the sample.
Graphene (planar C24) is a flat sheet of carbon atoms, one atom thick, that has extraordinary strength, conductivity, elasticity and thinness.
“If confirmed with laboratory spectroscopy -- something that is almost impossible with the present techniques -- this would be the first detection of graphene in space,” said team member Garcia-Hernández.
“The Spitzer Space Telescope has been amazingly important for studying complex organic molecules in stellar environments,” said Stanghellini.
“We are now at the stage of not only detecting fullerenes and other molecules, but starting to understand how they form and evolve in stars,” she added.