Universe's first stars left unique chemical signatures

"With this new measurement, we have significantly improved the precision of this rate for stellar modeling," researcher Brian Bucher said
By Brooks Hays  |  July 1, 2015 at 10:30 AM
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LIVERMORE, Calif., July 1 (UPI) -- Researchers at Lawrence Livermore National Laboratory are on the case of the missing alpha star signatures. Scientist Brian Bucher recently made a breakthrough in predicting what the universe's first generation of stars might look like -- chemically speaking.

The cosmos' original stars were different than today's stars. They didn't have the plethora of heavy elements common in the modern universe at their disposal. They had to make their own.

Thanks to their inventiveness, the elements that make life possible are now littered throughout the cosmos. But when the first stars were born, just 400 million years after the Big Bang, there was only hydrogen and helium. Fusion in the bellies of these original stars converted the two elements into an array of heavier ones -- oxygen, nitrogen, carbon, iron and others.

But to pinpoint the remnants of these ancient stars, researchers need a more precise understanding of what chemicals will be left over. What chemical patterns will give away their once-presence?

"It is vital to our understanding of the properties of the first stars and the formation of the first galaxies to verify the predicted composition of stellar ashes by comparing them to observational data," Bucher said in a press release.

The key to predicting chemical composition is modeling. But to build the proper models, scientists need to recreate chemical reactions in the lab. One of those elusive reactions is the fusion of two carbon nuclei into a magnesium nucleus and one neutron. It's a reaction that's been near impossible to capture.

But Bucher and his colleagues were finally able to do it -- observing the fusion at intense star-like energies using a lab accelerator.

"With this new measurement, we have significantly improved the precision of this rate for stellar modeling," Bucher said. "We've studied its impact on the resulting stellar abundance pattern predictions, helping to identify the signature of the universe's elusive first generation of stars and their supernovae."

The breakthrough was detailed in the journal Physical Review Letters.

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