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Space soccer balls are common

Artist's impression of buckyballs and PAHs in space

Artistic representation of buckyballs and polycyclic aromatic hydrocarbons around an R Coronae Borealis star rich in hydrogen. Image courtesy MultiMedia Service (IAC).

  • Buckyballs are large soccer ball-shaped molecules with 60 carbon atoms
  • They’ve been found on Earth, in meteorites, and now in deep space
  • Might have played a role in bringing material to Earth to kick-start life

OBSERVATIONS MADE WITH NASA’s Spitzer Space Telescope have provided surprises concerning the presence of buckminsterfullerenes, or “buckyballs,” the largest known molecules in space.

Buckyballs are made of 60 carbon atoms arranged in shape similar to a soccer ball, with patterns of alternating hexagons and pentagons. Their structure is reminiscent of Buckminster Fuller’s famous geodesic domes, for which they are named. These molecules are very stable and difficult to destroy.

A study of certain kinds of stars by David L. Lambert, Director of The University of Texas at Austin’s McDonald Observatory, and colleagues shows that buckyballs are more common in space than previously thought.

The team found that “buckyballs do not occur in very rare hydrogen-poor environments as previously thought, but in commonly found hydrogen-rich environments and, therefore, are more common in space than previously believed,” Lambert says.

Richard Curl, Harold Kroto, and Richard Smalley won the 1996 Nobel Prize in chemistry for synthesising buckyballs in a laboratory.

The consensus based on lab experiments has been that buckyballs do not form in space environments that have hydrogen, because the hydrogen would inhibit their formation.

Instead, the idea has been that stars with very little hydrogen but rich in carbon—such as the so-called R Coronae Borealis stars—provide an ideal environment for their formation in space.

Skeletal representation of a Buckyball

Skeletal representation of a Buckyball, with its obvious resemblance to a soccer ball.

Buckyballs more common than thought

Lambert, along with N. Kameswara Rao of the Indian Institute of Astrophysics and Domingo Anibal Garcia-Hernandez of the Instituto de Astrofisica de Canarias, put these theories to the test. They used the Spitzer Space Telescope to take infrared spectra of R Coronae Borealis stars to look for buckyballs in their chemical make-up.

They found these molecules do not occur in those R Coronae Borealis stars with little or no hydrogen, an observation contrary to expectation. The group also found that buckyballs do exist in the two R Coronae Borealis stars in their sample that contain a fair amount of hydrogen.

Studies published last year, including one by Garcia-Hernandez, showed that buckyballs were present in planetary nebulae rich in hydrogen.

Together, these results tell us that fullerenes are much more abundant than previously believed, because they are formed in normal and common “hydrogen-rich” and not rare “hydrogen-poor” environments.

The current observations have changed our understanding of how buckyballs form. It suggests they are created when ultraviolet radiation strikes dust grains or by collisions of gas.

The dust grains are vaporised, producing an interesting chemistry where buckyballs and polycyclic aromatic hydrocarbons (PAHs) are formed. PAHs are molecules of a variety of sizes are formed from carbon and hydrogen.

Buckyballs have been found on Earth and in meteorites, and now in space, and can act as “cages” to capture other atoms and molecules. Some theories suggest that the buckyballs may have carried to the Earth substances that make life possible.

The research will appear in the March 10 issue of The Astrophysical Journal.

Adapted from information issued by The University of Texas McDonald Observatory and the Instituto de Astrofisica de Canarias.

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Glimpse of glittering stars and gas

GLIMPSE360 and 2MASS image

Two bright stars illuminate clouds of gas in this false-colour image made from Spitzer Space Telescope GLIMPSE360 and Two Micron All Sky Survey data. The gas is composed of polycyclic aromatic hydrocarbons (PAHs), molecules that on Earth are found in car exhausts and grilled food on BBQs!

  • Spitzer space telescope making Milky Way map
  • Focusing on our galaxy’s outer reaches

NASA’s Spitzer space telescope—which is similar to the Hubble Space Telescope but is optimised to pick up infrared radiation (heat)—is partway through producing a huge map of the outskirts of our Milky Way galaxy.

Our galaxy is made up of a central bulge surrounded by octopus-like spiral arms. The overall shape is that of a disc…round, with a thicker middle and thinner edges.

Our Solar System is located on one of the spiral arms, about two-thirds of the way out from the central bulge.

The Galactic Legacy Infrared Mid-Plane Survey Extraordinaire 360, or GLIMPSE360, is a follow-up to the GLIMPSE and GLIMPSE3D surveys, which focused on the inner parts of our galaxy.

GLIMPSE360 will look outwards to where the Milky Way’s star fields begin to fade out and intergalactic space begins.

“GLIMPSE360 will see to the edge of the Milky Way galaxy better than any telescope has before,” says Barbara Whitney, principal investigator for the survey, Senior Scientist at the University of Wisconsin and a Senior Research Scientist at the Space Science Institute in Boulder, Colorado.

Astronomers don’t know much about the outer limits of the Milky Way, and a number of puzzles remain to be solved.

GLIMPSE360 and 2MASS image

The bubble in the centre of this gas cloud is being "inflated" by strong winds blown from young, hot stars. (False-colour image.)

One of them is how and why stars are born in regions where there is little star-making material—interstellar clouds of gas and dust.

“It’s like looking into the wilderness of our galaxy,” says Whitney. “While mapping the stars and dust out there, we hope to answer some major questions about an environment that is very different from the inner Milky Way.”

Studies of other galaxies have shown that there can be a surprising amount of star formation going on in the outer reaches.

Being an infrared telescope, Spitzer was launched with a cooling system to keep it’s own equipment very cold in order to prevent stray heat from interfering with its observations. But the coolant fluid ran out in early 2009, and the telescope has been operating in “warm mode” ever since. It can’t do quite the same observations as before, but it is still an incredibly capable facility that is in very good technical health.

“We look forward to what GLIMPSE360 will show us,” Whitney says. “The adventure is just getting started.”

Story by Jonathan Nally, Editor, SpaceInfo.com.au

Images courtesy NASA / JPL-Caltech / 2MASS / B. Whitney (SSI/University of Wisconsin).

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