HEAPOW: About to Go Boom (2010 Mar 22)

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bystander
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HEAPOW: About to Go Boom (2010 Mar 22)

Post by bystander » Tue Mar 23, 2010 4:24 pm

Image HEAPOW: About to Go Boom (2010 Mar 22)
Stars cook up chemicals deep within their cores. All stars start by converting hydrogen into helium; some convert helium into carbon; and rare stars convert carbon into oxygen, silicon and other heavier elements. All the way up to iron, at which point the star goes boom as a supernova. All this activity is hidden within the center of the star, but internal motions can bring material from the core to the surface, and the surface becomes increasingly "polluted" with heavier elements as a star ages. One old star about to explode is WR 142. WR 142 is a Wolf-Rayet star, an evolved form of a very massive star. Such stars explode so powerfully that they are believed to be the progenitors of some Gamma-ray bursts. WR 142 shows an overabundance of oxygen in its spectrum, indicating that the star has cooked up elements up to oxygen in its core, and is well on its way to the iron catastrophe which will trigger the violent death of the star. Above is an image of X-ray emission from WR 142 taken by the XMM-Newton Observatory. WR 142 appears as a very faint but real source (shown by the red arrow) near the center of the field of view. The XMM observations show that the X-rays produced have surprisingly high energy, perhaps indicating the importance of magnetic fields in the outer atmosphere of the star. Though how such star could produce magnetic fields (and energetic X-ray emission) is a puzzle, hopefully one that astronomers can solve before the star disappears for good.
XMM-Newton: X-ray image of star cluster Berkeley 87

Discovery of X-Ray Emission from the Wolf-Rayet Star WR 142 of Oxygen Subtype
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Re: HEAPOW: About to Go Boom (2010 Mar 22)

Post by wonderboy » Tue Mar 23, 2010 7:16 pm

It probably already has went boom! I wonder what its all about? Things like this get you thinkin like a mad man.
"I'm so fast that last night I turned off the light switch in my hotel room and was in bed before the room was dark" Muhammad Ali, faster than the speed of light?

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Re: HEAPOW: About to Go Boom (2010 Mar 22)

Post by The Code » Wed Mar 24, 2010 7:02 pm

bystander wrote:Image HEAPOW: About to Go Boom (2010 Mar 22)
The XMM observations show that the X-rays produced have surprisingly high energy, perhaps indicating the importance of magnetic fields in the outer atmosphere of the star. Though how such star could produce magnetic fields (and energetic X-ray emission) is a puzzle, hopefully one that astronomers can solve before the star disappears for good.
Question's:

Why is this a puzzle? What is wrong with the above?

Mark
Always trying to find the answers

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bystander
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Re: HEAPOW: About to Go Boom (2010 Mar 22)

Post by bystander » Thu Mar 25, 2010 7:30 pm

DOI: 10.1088/0004-637X/693/1/L44
We report the discovery of weak yet hard X-ray emission from the Wolf-Rayet (WR) star WR 142 with the XMM-Newton X-ray telescope. Being of spectral subtype WO2, WR 142 is a massive star in a very advanced evolutionary stage shortly before its explosion as a supernova or γ-ray burst. This is the first detection of X-ray emission from a WO-type star. ... The hard X-ray spectrum suggests a plasma temperature of about 100 MK. Commonly, X-ray emission from stellar winds is attributed to embedded shocks due to the intrinsic instability of the radiation driving. From qualitative considerations we conclude that this mechanism cannot account for the hardness of the observed radiation. There are no hints for a binary companion. Therefore the only remaining, albeit speculative explanation must refer to magnetic activity.