Cosmic collisions spin stellar corpses into gold
Rumpelstiltskin would be jealous. A recently observed flash in the distant universe suggests that smacking two dense, dead stars together can create gold in vast amounts – with a mass 10 times that of the moon. The finding may help settle a debate about whether colliding stars or supernovae are the main sources of heavy metals in the universe.
"We see a signature that we interpret as the production of very heavy elements – gold, platinum, lead – exactly the kind of material whose origin was unclear," says Edo Berger of the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
After the big bang, the universe contained only hydrogen, helium and lithium. Most of the other elements are built up in the cores of massive stars, and released when stars die. But stars lack the energy and the spare neutrons to be able to forge elements heavier than iron.
One idea often put forward to explain how such elements are made is that supernovae explosions of massive stars produce a powerful, fast-moving wind of freed neutrons and protons, which can convert lighter atomic nuclei released during the explosion into those of heavier elements.
But computer simulations of the process did not always produce the proportions seen in nature of certain elements. Some researchers suggested that neutron stars, the dense balls of mostly neutrons that are left over after a supernova, could build heavy elements more efficiently when they collide.
http://www.newscientist.com/article/dn23886-cosmic-collisions-spin-stellar-corpses-into-gold.html#.VH9tYcn4InH
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