Dance of the dead.The neutron star neutron star, extremely small, extremely dense star, about double the sun's mass but only a few kilometers in radius, in the final stage of stellar evolution. Astronomers Baade and Zwicky predicted the existence of neutron stars in 1933. XTE XTE X-Ray Timing Explorer XTE Cross Track Error J1739-285 is the burned-out remains of what was once a brilliant celestial body. Now, astronomers have evidence that it's the fastest-spinning stellar corpse known. X-ray observations indicate that the neutron star spins 1,122 times a second, about 30 percent faster than the previous record holder, report Phil Kaaret of the University of Iowa Not to be confused with Iowa State University. The first faculty offered instruction at the University in March 1855 to students in the Old Mechanics Building, situated where Seashore Hall is now. In September 1855, the student body numbered 124, of which, 41 were women. in Iowa City Iowa City, city (1990 pop. 59,738), seat of Johnson co., E Iowa, on both sides of the Iowa River; founded 1839 as the capital of Iowa Territory, inc. 1853. Among its manufactures are foam rubber, animal feed, paper, and food products. The city is the seat of the Univ. and his colleagues in the March 10 Astrophysical Journal Letters. NASA's Rossi X-ray Timing Explorer The Rossi X-ray Timing Explorer (RXTE) satellite observes the fast-moving, high-energy worlds of black holes, neutron stars, X-ray pulsars and bursts of X-rays that light up the sky and then disappear forever. discovered the neutron star in 1999 when it emitted bursts of X rays. After several years of quiescence, it began sending out new bursts in 2005. Studies of other neutron stars had shown that variations in the brightness of X-ray bursts indicate the stars' rotation rates. Late last year, the Rossi telescope found oscillations oscillations See Cortical oscillations. indicating that XTE J1739-285 was spinning faster than any neutron star previously observed. Since then, the star has again quieted, and scientists are waiting to observe more bursts to confirm the high spin rate, Kaaret and his team say. The maximum rotation of a neutron star would reveal its composition, notes Kaaret. For instance, an interior composed solely of electrons and protons squeezed together into neutrons can't be compressed as much as more-exotic particles can and so can't rotate as rapidly. Additional studies of the spin rates of neutron stars might let astronomers rule out some estimates of the objects' compositions.--R.C. |
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