back to article Little bear harbouring isolated neutron star

A group of American and Canadian astronomers have spotted what appears to be an isolated neutron star relatively near to Earth, the BBC reports. It is very rare for neutron stars to be found in singles: usually they have a companion supernova remnant for company. If it is confirmed, it will be only the eighth known lone neutron …

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Iron doesn't ignite!

When a massive star runs out of hydrogen in its core, the core collapses under gravity, raising the temperature and pressure until the helium starts to fuse to form carbon. This process repeats until the core is mainly composed of iron. As iron is one of the most stable elements in the universe, further fusion does not generate the heat required to balance the relentless pressure of gravity and the core continues to collapse unless electron or neutron degeneracy pressure can balance the gravitional pull.

The iron never "ignites"!

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Bliar again

I blame the government (or the Caledonian Occupation Authority, if you're English).

Before we had these pinko-liberals in charge, we only ever had normal, healthy neutron stars.

Now after 10 years of Bliar, and with Fat Gordy as commissar-in-chief, all sorts of deviant stars etc. are crawling out of the woodwork - or at least that's where they'd crawl out of, were there any woodwork 1000 light years away...........

I've already got my coat...

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Sounds heavy

How far away is it? Hopefully more than 20,000 average earth cities away, otherwise I'm running home scared (approximately three average roads away)

Hehe I love The Reg's quirks...Keep 'em coming....

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So...

What exactly is the size of the average city, say in cubic furlongs? We should be told.

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I'm no expert

I'm no astronomer but I thought neutron starts only emitted EM energy from their poles? If that is indeed the case I would hardly find it surprising that we couldn't see these emanations if the starts poles don't point at us.

It would also infer that there could be many neutron stars sitting out there in places we don't expect (i.e. above the main plane of our galaxy) that we just can't see. No?

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And the IT angle is?

More non IT news on a supposedly IT news website!

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Anonymous Coward

Close...

> A neutron star is what is left after a massive star goes

> supernova. After the explosion throws off the star's outer layers,

> the remaining material continues to burn until the iron in the star's

> core ignites. Then it collapses under its own gravity, fusing

> protons and electrons to form neutrons.

The latter stages of a giant star involve the fusion of light elements forming elements up to iron, which is the last element that can be produced exothermically. From this point, an onion skin layering of lighter elements is formed that is held up by electron degeneracy pressure within an iron-nickel core. Once this core exceeds 1.44 solar masses, electron degeneracy pressure can't hold it and the whole thing collapses rather quickly to form a degenerate neutron core. At this point, the rest of the infalling star "bounces" off forming a shock wave. The material then stalls, but reabsorbs energy from a massive burst of neutrinos from the exceedingly hot core, and thus forms the subsequent explosion we see.

All the "heavy" elements above iron are formed as a result of the collapse and subsequent energy release (through neutron capture, and other proposed mechanisms) - these are all endothermic reactions and cannot be formed during the life of the star .

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@eddiewrenn

"There's that word again; 'heavy'. Why are things so heavy in the future? Is there a problem with the earth's gravitational pull?"

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I'll bet big Daddy bear

is harbouring a spectacularly heavy pair.

And furthermore, I can assert with impeccable logic and absolute certainty, that they either are neutron stars or they are not neutron stars.

So, having paid for years for scientific researchers to come up with the obvious, we are now paying them to come up with tautologies.

(Note for USA readers - in the UK, it's the Great Bear, never the Big Dipper. Mind you, this could be the start of a change).

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Anonymous Coward

Aren't we humans quaint

"It is very rare for blah blah blah"

I'm willing to bet that in the effectively infinite universe, NOTHING is rare. Let alone VERY rare. We touch our toe in the water and think we know the depths of the ocean.

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Kelvins eh?

So if the difference between Kelvin and Celsius is a paltry 273 degrees at the bottom end does it really make that much difference around the 10 million mark?

Or was that some techno bable with which to force us into idiot mode?

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Re: So ...

So...

By Juhani Vehvilainen

Posted Tuesday 21st August 2007 11:55 GMT

"What exactly is the size of the average city, say in cubic furlongs? We should be told."

Smaller than Wales, but bigger than Stevenage. :-)

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