Heavyweight Stars Light Up Nebula NGC 6357
The small open star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 in Sagittarius, about 8,000 light-years away from Earth. Some of the stars in this cluster are extremely massive and emit intense ultraviolet radiation.The brightest object in the picture is designated Pismis 24-1. |
by Staff Writers
Baltimore MDs (SPX) Dec 14, 2006
The small open star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 in Sagittarius, about 8,000 light-years away from Earth. Some of the stars in this cluster are extremely massive and emit intense ultraviolet radiation. The brightest object in the picture is designated Pismis 24-1.
It was once thought to weigh as much as 200 to 300 solar masses. This would not only have made it by far the most massive known star in the galaxy, but would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars.
However, high-resolution Hubble Space Telescope images of the star show that it is really two stars orbiting one another (inset pictures at top right and bottom right). They are estimated to each be 100 solar masses. The Hubble Advanced Camera for Surveys images were taken in April 2006.
Related Links
Stellar Chemistry, The Universe And All Within It
Encyclopedia Of Stars Aimed At Anyone Who Enjoys Astronomy
Champaign IL (SPX) Dec 13, 2006
An astronomy expert looking for in-depth research about stars can consult the same new reference book that an undergraduate freshman with a limited knowledge of astronomy might use. "The Cambridge Encyclopedia of Stars," by James B. Kaler, a professor emeritus of astronomy at the University of Illinois at Urbana-Champaign, covers topics from ancient to modern times.
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