ESO’s Very Large Telescope has captured the first time-lapse movie of a rare shell ejected by a “vampire star." The gas-sucking star is part of a double star system known as V445 in the constellation of Puppis ("the Stern") that is devouring part of a companion star looks to be a ticking time bomb. It appears that this double star system is a prime candidate to be one of the long-sought progenitors of the exploding stars known as Type Ia supernovae, critical for studies of dark energy. In November 2000, this system underwent a nova outburst, becoming 250 times brighter than before and ejecting a large quantity of matter into space.
“One of the major problems in modern astrophysics is the fact that we still do not know exactly what kinds of stellar system explode as a Type Ia supernova,” says Patrick Woudt, from the University of Cape Town and lead author of the paper reporting the results. “As these supernovae play a crucial role in showing that the Universe’s expansion is currently accelerating, pushed by a mysterious dark energy, it is rather embarrassing.”
The astronomers studied the object known as V445 in the constellation of Puppis (“the Stern”) -the first, and so far only, nova showing no evidence at all for hydrogen. It provides the first evidence for an outburst on the surface of a white dwarf dominated by helium. “This is critical, as we know that Type Ia supernovae lack hydrogen,” says co-author Danny Steeghs, from the University of Warwick, UK, “and the companion star in V445 Pup fits this nicely by also lacking hydrogen, instead dumping mainly helium gas onto the white dwarf.”
SNIP...............
A supernova is one way that a star can end its life, exploding in a display of grandiose fireworks. One family of supernovae, called Type Ia supernovae, are of particular interest in cosmology as they can be used as “standard candles” to measure distances in the Universe and so can be used to calibrate the accelerating expansion that is driven by dark energy.
http://www.dailygalaxy.com/my_weblog/2009/11/-vampire-star-may-unlock-clues-to-secret-of-dark-energy.htmltime lapse artist's interpretation from the ESO
http://www.eso.org/gallery/v/Videos/Stars/vid-43b-09_FLASH.flv.html
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