ASU astrophysicist part of team that has discovered solid buckyballs in space
Sumner Starrfield, Regents’ Professor of Astrophysics in the School of Earth and Space Exploration at Arizona State University, is part of an international team that has, for the first time, discovered buckyballs in a solid form in space. Prior to this discovery, the microscopic carbon spheres had been found only in gas form in the cosmos.
Formally named buckminsterfullerene, buckyballs are named after their resemblance to the late architect Buckminster Fuller’s geodesic domes. They are made up of 60 carbon atoms arranged into a hollow sphere, like a soccer ball.
In the latest discovery, scientists used data from NASA’s Spitzer Space Telescope to detect tiny particles consisting of stacked buckyballs. They found the particles around a pair of stars called “XX Ophiuchi” that are 6,500 light-years from Earth, and detected enough to fill the equivalent in volume to 10,000 Mount Everests.
“These buckyballs are stacked together to form a solid, like oranges in a crate,” said Nye Evans of Keele University in England, lead author of a paper appearing in the Monthly Notices of the Royal Astronomical Society. “The particles we detected are minuscule, far smaller than the width of a hair, but each one would contain stacks of millions of buckyballs.”
Buckyballs were detected definitively in space for the first time by Spitzer in 2010. Spitzer later identified the molecules in a host of different cosmic environments. It even found them in staggering quantities, the equivalent in mass to 15 Earth moons, in a nearby galaxy called the Small Magellanic Cloud.
In all of those cases, the molecules were in the form of gas. The recent discovery of buckyballs particles means that large quantities of these molecules must be present in some stellar environments in order to link up and form solid particles. The research team was able to identify the solid form of buckyballs in the Spitzer data because they emit light in a unique way that differs from the gaseous form.
Starrfield, who has been using Spitzer to obtain infrared spectra of a number of recent stars, including XX Ophiuchi, was involved in writing the proposal to conduct the observations with Spitzer. He also was involved in analyzing and interpreting the data. The team chose XX Ophiuchi because it was already known to be a puzzling system of stars. Although the researchers did not expect to find buckyballs, they performed an extremely careful analysis of the light emitted by this stellar system and were on the alert for any unusual signals.
Starrfield has been using Spitzer because “its infrared detectors are superb for studying cold objects in the universe, much colder than our own Sun. We had known that buckyball molecules had been discovered around a few other stars but never expected to find them collected together in small particles.” According to Starrfield, “We have now identified features in the infrared that convince us that solid buckyball particles exist. Astronomers can now search for these same features in other stars that emit infrared light and hopefully find a lot of these particles.”
Buckyballs have been found on Earth in various forms. They form as a gas from burning candles and exist as solids in certain types of rock, such as the mineral shungite found in Russia, and fulgurite, a glassy rock from Colorado that forms when lightning strikes the ground. In a test tube, the solids take on the form of dark, brown “goo.”
“Buckyballs were studied by Sumio Ijima, a solid state physicist in Japan who was actually at ASU from 1970 to 1982,” says Starrfield. “So, we were pleased to continue his studies in space. They have been under continuous study for decades with possible uses in drug delivery and armor.”
“The window Spitzer provides into the infrared universe has revealed beautiful structure on a cosmic scale,” said Bill Danchi, Spitzer program scientist at NASA Headquarters in Washington. “In yet another surprise discovery from the mission, we’re lucky enough to see elegant structure at one of the smallest scales, teaching us about the internal architecture of existence.”