Massive size has scientists gushing over obese star
Source: Agencies |
July 22, 2010, Thursday
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A HUGE ball of brightly burning gas drifting through a neighboring galaxy may be the heaviest star ever discovered - hundreds of times more massive than the sun, scientists said yesterday after working out its weight for the first time.
Those behind the find say the star, called R136a1, may once have weighed as much as 320 solar masses. Astrophysicist Paul Crowther said the obese star - twice as heavy as any previously discovered - has already slimmed down considerably over its lifetime. In fact, it's burning itself off with such intensity that it shines at nearly 10 million times the luminosity of the sun.
"Unlike humans, these stars are born heavy and lose weight as they age," said Crowther, an astrophysicist at the University of Sheffield in northern England. "R136a1 is already middle-aged and has undergone an intense weight-loss program."
Cloud of gas
Crowther said the giant was identified at the center of a star cluster in the Tarantula Nebula, a sprawling cloud of gas and dust in the Large Magellanic Cloud, a galaxy about 165,000 light-years away from our own Milky Way.
The star was the most massive of several giants identified by Crowther and his team in an article in the Monthly Notices of the Royal Astronomical Society.
While other stars can be larger, notably the swollen crimson-colored ones known as red giants, they weigh far less. Still, the mass of R136a1 and its ilk means they're tens of times bigger than the Earth's sun and they're brighter and hotter, too.
Surface temperatures can surpass 40,000 degrees Celsius, seven times hotter than the sun. They're also several million times brighter, because the greedy giants tear through their energy reserves far faster than smaller stars. This means that massive stars live fast and die young, quickly shedding huge amounts of material and burning themselves out.
"The biggest live only 3 million years," Crowther said. "In astronomy that's a very short time."
Those behind the find say the star, called R136a1, may once have weighed as much as 320 solar masses. Astrophysicist Paul Crowther said the obese star - twice as heavy as any previously discovered - has already slimmed down considerably over its lifetime. In fact, it's burning itself off with such intensity that it shines at nearly 10 million times the luminosity of the sun.
"Unlike humans, these stars are born heavy and lose weight as they age," said Crowther, an astrophysicist at the University of Sheffield in northern England. "R136a1 is already middle-aged and has undergone an intense weight-loss program."
Cloud of gas
Crowther said the giant was identified at the center of a star cluster in the Tarantula Nebula, a sprawling cloud of gas and dust in the Large Magellanic Cloud, a galaxy about 165,000 light-years away from our own Milky Way.
The star was the most massive of several giants identified by Crowther and his team in an article in the Monthly Notices of the Royal Astronomical Society.
While other stars can be larger, notably the swollen crimson-colored ones known as red giants, they weigh far less. Still, the mass of R136a1 and its ilk means they're tens of times bigger than the Earth's sun and they're brighter and hotter, too.
Surface temperatures can surpass 40,000 degrees Celsius, seven times hotter than the sun. They're also several million times brighter, because the greedy giants tear through their energy reserves far faster than smaller stars. This means that massive stars live fast and die young, quickly shedding huge amounts of material and burning themselves out.
"The biggest live only 3 million years," Crowther said. "In astronomy that's a very short time."
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