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Dead Star Has a Ring, But No Plans for a
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NASA's Spitzer Space
Telescope has found a bizarre ring of material around the magnetic remains of a
star that essentially blew up. Also known as SGR 1900+14, this
dead star belongs to a class of objects known as magnetars, which are
cores of massive stars that blew up in supernova explosions. However, unlike
other dead stars, they slowly pulsate with X-rays and have extremely strong
magnetic fields. Scientists believe the ring was formed in 1998 when the
magnetar erupted in a giant flare resulting in the crusty surface of the
magnetar to crack. This resulted in sending out a flare, or blast of energy,
that excavated a nearby cloud of dust, leaving an outer, dusty ring. This ring
is oblong, with dimensions of about seven by three light-years, and appears to
be flat, or two-dimensional. However, the scientists said they can't rule out
the possibility of a three-dimensional shell.
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Rings and spheres are common in the universe.
Young, hot stars blow bubbles in space, carving out dust into spherical shapes.
When stars die in supernova explosions, their remains are blasted into space,
forming short-lived beautiful orbs called supernova remnants. Rings can also
form around exploded stars whose expanding shells of debris ram into
pre-existing dust rings, causing the dust to glow, as is the case with the
supernova remnant called 1987A. But the ring around the magnetar SGR
1900+14 fits into none of these categories. For one thing, supernova remnants
and the ring around 1987A cry out with X-rays and radio waves. The ring
around SGR 1900+14 only glows at specific infrared wavelengths that Spitzer can
see. "The universe is a big place and weird things can happen," said
Stefanie Wachter of NASA's Spitzer Science Center at the California
Institute of Technology, Pasadena, who found the ring serendipitously. "I
was flipping through archived Spitzer data of the object, and that's when I
noticed it was surrounded by a ring we'd never seen before." Wachter is lead
author of a paper about the findings in this week's Nature—Huntsville,
Alabama
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