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Newly Seen Force May Help Gravity In Star Formation
Greenbelt MD (SPX) Mar 02, 2005 Scientists have pierced through a dusty stellar nursery to capture the earliest and most detailed view of a collapsing gas cloud turning into a star, analogous to a baby's first ultrasound. The observation, made primarily with the European Space Agency's XMM-Newton observatory, suggests that some unrealized, energetic process - likely related to magnetic fields - is superheating the surface of the cloud core, nudging the cloud ever closer to becoming a star. The observation marks the first clear detection of X-rays from a cold precursor to a star, called a Class 0 protostar, far earlier in a star's evolution than most experts in this field thought possible. The surprise detection of X-rays from such a cold object reveals that matter is falling toward the protostar core 10 times faster than expected from gravity alone. "We are seeing star formation at its embryonic stage," said Dr. Kenji Hamaguchi, a NASA-funded researcher at NASA Goddard Space Flight Center in Greenbelt, Md., lead author on a report in The Astrophysical Journal. "Previous observations have captured the shape of such gas clouds but have never been able to peer inside. The detection of X-rays this early indicates that gravity alone is not the only force shaping young stars." Supporting data came from NASA's Chandra X-ray Observatory, Japan's Subaru telescope in Hawaii, and the University of Hawaii 88-inch telescope. Hamaguchi's team discovered X-rays from a Class 0 protostar in the R Corona Australis star-forming region, about 500 light years from Earth. Class 0 is the youngest class of protostellar object, about 10,000 to 100,000 years into the assimilation process. The cloud temperature is about 400 degrees below zero Fahrenheit (minus 240 Celsius). After a few million years, nuclear fusion ignites at the center of the collapsing protostellar cloud, and a new star is formed.
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