EXPLODING STAR CAUGHT ON TAPE
Call it fantastic timing. Early this year, a group of astronomers
led by Princeton University's Alicia Soderberg were using NASA's
Swift satellite to observe a new supernova-one of those spectacular
explosions that mark the end of a massive star's life. This
supernova was in a galaxy some 100 million light years away. It was
relatively unremarkable, Soderberg admits. But then something
extraordinary happened. On January 9, in what some astronomers are
calling a remarkable stroke of good luck, another star in their
field of view went supernova. "We actually watched the star
explode," says Soderberg, who was in Michigan, talking to an
audience of fellow scientists about her research when the call about
the supernova came from her colleague. This set off a week of
scrambling to get astronomers across the globe to point telescopes
at the supernova to confirm and better study the phenomenon.

Astronomers have never before seen a star at the first moments of
its explosive death. Usually, astronomers miss the earliest flash
of a supernova because the explosion is only visible to orbiting
x-ray detectors on platforms like Swift. In the 22 May 2008 issue of
Nature, Soderberg and her colleagues describe how the supernova's
initial burst lasted a few minutes and then faded away. Its power
was remarkable. In 10 minutes, the exploding star expelled the about
the same amount of energy as the sun puts out in 82,000 years.

"It's incredibly serendipitous," says Harvard astrophysics professor
Josh Grindlay, a supernova expert who was not involved in the
research. "This almost certainly provides a whole new way of
detecting supernovae." Though astronomers have known about
supernovas for hundreds of years, the events are rare, only seen
about once a century in any given galaxy. They are only visible to
the eye or to ordinary telescopes a few weeks after the initial
burst, when the supernova begins to shine brightly-sometimes
becoming one of the brightest objects in the evening sky.
Supernovae are remarkable events not only for such displays of power
but because they culminate a natural process of stellar renewal-sort
of like cosmological compost. ...

(Physics News)