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Trillions of wrecked comets formed star's icy halo BY STEPHEN CLARK SPACEFLIGHT NOW Posted: April 13, 2012 Using images from Europe's Herschel infrared space telescope, astronomers have obtained fresh insights into a forming solar system around the nearby star Fomalhaut, which features a ring of fine icy dust grains born out of the annihilation of thousands of comets each day.
"These beautiful Herschel images have provided the crucial information needed to model the nature of the dust belt around Fomalhaut," said Goran Pilbratt, ESA's Herschel project scientist. Researchers discovered Fomalhaut's dust ring in the 1980s, but Herschel's data provide constraints on the temperature and size of the dust particles. The dust grains are only a few millionths of a meter across, and their temperatures are between minus 284 degrees and minus 382 degrees Fahrenheit, scientists announced.
"To sustain the belt, the rate of collisions must be impressive: each day, the equivalent of either two 10 km-sized [6.2-mile] comets or 2,000 1 km-sized [.62-mile] comets must be completely crushed into small fluffy, dust particles," a statement released by NASA's Jet Propulsion Laboratory said. "I was really surprised," Acke said. "To me this was an extremely large number." NASA contributes to the European-led Herschel mission. Scientists estimate there are between 260 billion and 8.3 trillion comets in the Fomalhaut belt. Our solar system's Oort cloud, a vast cloud of objects lying up to 100,000 times further from the sun than Earth, is believed to harbor a similar number of icy bodies. Astronomers believe at least one planet orbits Fomalhaut between the star and the debris ring. |
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