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NASA Researchers Strike Scientific Gold With Meteorite

January 3, 2013 Leave a comment

Scientists found treasure when they studied a meteorite that was recovered April 22, 2012 at Sutter’s Mill, the gold discovery site that led to the 1849 California Gold Rush. Detection of the falling meteorites by Doppler weather radar allowed for rapid recovery so that scientists could study for the first time a primitive meteorite with little exposure to the elements, providing the most pristine look yet at the surface of primitive asteroids.

An international team of 70 researchers reported in today’s issue of “Science” that this meteorite was classified as a Carbonaceous-Mighei or CM-type carbonaceous chondrite and that they were able to identify for the first time the source region of these meteorites.

“The small three meter-sized asteroid that impacted over California’s Sierra Nevada came in at twice the speed of typical meteorite falls,” said lead author and meteor astronomer Peter Jenniskens of the SETI Institute, Mountain View, Calif., and NASA Ames Research Center, Moffett Field, Calif. “Clocked at 64,000 miles per hour, it was the biggest impact over land since the impact of the four meter-sized asteroid 2008 TC3, four years ago over Sudan.”

Full Story: http://www.nasa.gov/centers/ames/news/releases/2012/12-93AR.html

How White Dwarfs Mimic Black Holes

January 3, 2013 Leave a comment

The Southampton Physics and Astronomy team are part of a global collaboration – with colleagues in Taiwan, South Africa, Poland, Australia and Italy – that has revealed that bright X-ray flares in nearby galaxies, once assumed to indicate the presence of black holes, can in fact be produced by white dwarfs.

They made the discovery by detecting a dramatic, short-lived X-ray flare that was picked up by an X-ray telescope on the International Space Station.

Using optical telescopes in South Africa and Chile, the Southampton astronomers showed that the flare, called XRF111111 as it happened on 11 November, 2011, was located in the Small Magellanic Cloud. These Magellanic Clouds are between 160,000 and 200,000 light years away and are the nearest satellite galaxies to the Milky Way. They are visible to the naked eye from the Southern Hemisphere.

The flare from XRF111111 was so luminous that astronomers initially thought it was likely to be a black hole producing X-rays but further research by Phil and his team revealed that its X-ray temperature was so low that it had to be a white dwarf instead.

Full Story: http://www.southampton.ac.uk/mediacentre/news/2012/dec/12_222.shtml