Supernova remnant contains \'loner\' noble gas in rare combination

Argon, a gas termed a loner for its refusal to bond with other elements, has been seen linked with a chemical partner in a distant nebula, U.S. astronomers say. In the Crab Nebula, the remains of an exploded star, astronomers have found the first evidence of such a compound in space, a molecule called argon hydride, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Thursday. Argon, like helium and neon and a few others, is one of the so-called noble gases, named for their reluctance to bind in compounds with more common elements. Rarely engaging in chemical reactions, noble gases prefer to go it alone, astronomers said. "The strange thing is that it is the harsh conditions in a supernova remnant that seem to be responsible for some of the argon finding a partner with hydrogen," JPL scientist Paul Goldsmith said. The discovery was made in spectral data from the Herschel space observatory, a European Space Agency mission with important NASA contributions. "This is not only the first detection of a noble-gas based molecule in space, but also a new perspective on the Crab nebula," ESA Herschel project scientist Goran Pilbratt said. "Herschel has directly measured the argon isotope we expect to be produced via explosive nucleosynthesis in a core-collapse supernova, refining our understanding of the origin of this supernova remnant," he said.