New Type of Exotic Star Proposed -Electroweak stars

[MeteorWayne]

http://www.space.com/scienceastronomy/e ... 00122.html

Scientists have proposed a new class of star, one that has an exotic stellar engine that would emit mostly hard-to-detect neutrinos instead of photons of light like regular stars.

These objects, dubbed "electroweak stars," are plausible because of the Standard Model of physics – though none have been detected yet – partly because they wouldn't shine very brightly in visible light.

A team of physicists led by Glenn Starkman of Ohio's Case Western Reserve University describe the structure of such stars in a paper recently submitted to the journal Physical Review Letters.

An electroweak star could come into being toward the end of a massive star's life, after nuclear fusion has stopped in its core, but before the star collapses into a black hole, the researchers found.

At this point, the temperature and density inside a star could be so high, subatomic particles called quarks (which are the building blocks of protons and neutrons) could be converted into lighter particles called leptons, which include electrons and neutrinos...

If electroweak stars do exist, they could last at least 10 million years, the physicists found.

"This is long enough to represent a new stage in the evolution of a star if stellar evolution can take it there," the researchers wrote

 

[kg]

Does this mean that electroweak stars collapse into black holes after 10 million years or do they just stop emitting neutrinos? I had allways thought that a super nova left an object dense enough to form either a neutron star or a black hole, how does this objects density increase over time to the point of collapsing into a black hole? If it's emitting huge amounts of energy in the form of neutrios isn't it loosing mass? Does it cool enough in just 10 million years to condense into a black hole? This all sounds very strange to me.

 

[Saiph]

The standard path for a massive star to die is:

1*Core fusion stops, cools as energy is dumped into energy-wasteful iron fusion reactions.

2*The slighly cooled core rapidly collapses into a BH (in matter of minutes)

3*The sudden lack of support causes the outer envelope of the star to rush inwards.

4*The material meets near the core, rebounds and explodes in a supernova.


This new idea merely says some stars may have a step between steps 1 and 2 above.

It'll be:

1* Core fusion stops, core cools

2* Conditions are such that neutrino and lepton radiative pressure support the star for up to 10 million years

3* Then the core collapses....and the cycle to BH creation and supernova continue.


So this extra stage merely adds to the complexity and time scale..but doeasn't alter the big picture.

 

[kg]

Can neutrinos and leptons create enough radiative pressure to keep an electroweak star from collapsing into a black hole? I thought neutrinos would pass strait through and out of the star taking energy away from the star. Are these stars dense enough to keep the neutrinos from excaping?

 

[Saiph]

I wouldn't have thought so myself. But then again that's the entire point of this paper...to show that it could be possible.

So unless they're wrong...yes, yes it could

 

[EarthlingX]

Is it possible that regular massive stars also have such a phase, just shorter, not in million years, maybe 10, 100, 1000 ? That would make supernovas predictable, correct ?