A whimsical thought about Neutron Stars...and Quark Stars

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Sanjuricus
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A whimsical thought about Neutron Stars...and Quark Stars

Postby Sanjuricus » Thu Aug 18, 2011 12:44 pm UTC

I understand the concept of stellar remnants: White Dwarfs are powered by the metaphorical cars driving round a full car park analogy, Neutron stars are where the density is such that Electrons and Protons forget all past transgressions and become best buddies....and I'm vaguely aware that the posited Quark stars are a continuation of this process being just short of the densities required to achieve singularity.

...but the thought I had was what would happen to the neutronium in a neutron star if you were actually to create some sort of mythically strong machine that could extract the "as heavy as Mt Everest" teaspoon full of Neutronium and move it away from the gravity and pressure of the neutron star?
I'm assuming you would be in possession of a lot of rapidly expanding matter as the superfluid "boiled" away into hydrogen atoms as the neutrons decayed into a proton and an electron (as well as the radiation that this process emits) but something is missing.
**In any answers that you are able and kind enough to provide, assume that this mythical megalith of a machine can maintain a simulation of the gravity and pressure conditions of the neutron star around the extracted sample and can release this in a very short period of time once its moved to a safe distance. **

Also: An explanation of the processes that keep Pulsars and Magnetars going would be interesting, I've read quite a lot about how they are formed and what they are made of and how they behave but very little about what keeps them going. In White Dwarfs it is the Pauli Exclusion principle that basically fuels the fire so to speak...but what is the process for stars with no or little free electrons?
Answers on a strange quark to........

Also Also: A similar question about Quark stars assuming they do exist would be an added bonus in my quest to understand the universe! :)
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Xanthir » Thu Aug 18, 2011 3:43 pm UTC

Sanjuricus wrote:I'm assuming you would be in possession of a lot of rapidly expanding matter as the superfluid "boiled" away into hydrogen atoms as the neutrons decayed into a proton and an electron (as well as the radiation that this process emits) but something is missing.

What's missing? That's almost certainly the correct answer. (I don't think the neutrons would immediately decay, but you'd at least get a rapidly expanding cloud of neutrons.)
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Sanjuricus » Thu Aug 18, 2011 4:02 pm UTC

If I'm largely correct in what I'm saying then that's cool...I just thought that there might be something odd occurring as an intermediary stage in the expansion from superfluid (degenerate matter?) to "matter". :)

I'm also interested in the behaviour of matter in conditions that fall just short of Black Hole conditions...ie: No event horizon and no singularity but very close to possessing those properties.... :)
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Tass » Thu Aug 18, 2011 4:06 pm UTC

Xanthir wrote:
Sanjuricus wrote:I'm assuming you would be in possession of a lot of rapidly expanding matter as the superfluid "boiled" away into hydrogen atoms as the neutrons decayed into a proton and an electron (as well as the radiation that this process emits) but something is missing.

What's missing? That's almost certainly the correct answer. (I don't think the neutrons would immediately decay, but you'd at least get a rapidly expanding cloud of neutrons.)


I am fairly certain that is the answer too. An explosion of neutrons, subsequently decaying with their around 15 minutes half-life.

Sanjuricus wrote:In White Dwarfs it is the Pauli Exclusion principle that basically fuels the fire so to speak


What do you mean "fuels the fire", it just keeps them from collapsing further.

Sanjuricus wrote:An explanation of the processes that keep Pulsars and Magnetars going would be interesting


Inertia keeps them going (for a while, after that they become regular neutron stars).

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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby thoughtfully » Thu Aug 18, 2011 7:29 pm UTC

With respect to the Pauli Exclusion Principle: that is what stops the collapse. It applies to all fermions, and neutrons are fermions. The collapse to a neutron star occurs because the gravity is so high that the electrons must have a velocity greater than c to maintain the degeneracy pressure, and they can't do that, so they merge with the protons and the same principle comes to play again, but with neutrons as the actors.

What "fuels" a white dwarf is simply its temperature. Its luminosity comes from latent heat, not from fusion or any power source. When it cools off, it becomes a black dwarf, but that timescale is longer than the age of the Universe, so we don't expect that there are any black dwarfs around. Neutron stars are hot, too, but they are so tiny that it's difficult to see them, and also a lot of the emission is in very high frequencies, up to x-rays, I believe, which may not penetrate the atmosphere.

Pulsars are "fueled", as has been pointed out, by the enormous angular momentum generated by collapsing a huge spinning body down to something so tiny. But dragging a radio beam through space takes energy, and there isn't any energy generation going on in neutron stars either, so they spin down gradually. They can get revved up, however, if some infalling matter from a companion star gives their angular momentum some juice. This is the sort of thing that gets astronomers scratching their heads for a bit until they figure it out :)

Quark stars are speculative critters, but the same principles would apply. A sample lifted out by your magic machine would gradually revert in inverse order through these phases as the pressure was removed. Neutron stars have a crust of degenerate iron, for instance.
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Sanjuricus » Fri Aug 19, 2011 10:16 am UTC

Cool, thanks for the explanations. :) My mind has just expanded 0.001% :D
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Soralin » Fri Aug 19, 2011 10:41 am UTC

thoughtfully wrote:Neutron stars are hot, too, but they are so tiny that it's difficult to see them, and also a lot of the emission is in very high frequencies, up to x-rays, I believe, which may not penetrate the atmosphere.

Another interesting bit of information, Neutron stars actually apparently emit most of their heat in the form of neutrinos. :) http://www.astrophysicsspectator.com/to ... oling.html

Mostly through stuff like this, or with additional mediating particles:
n → p + e + ν
p + e → n + ν†

Protons and electrons merging into neutrons, but the opposite also ends up happening as well. And with each transition, neutrinos, or anti-neutrinos get emitted in the process, and carry away energy.

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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby thoughtfully » Fri Aug 19, 2011 12:23 pm UTC

Man, I knew neutron stars were freaky but the core cooling off faster than the outer layers? That really warps my mind, man!
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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby dockaon » Fri Aug 19, 2011 12:55 pm UTC

With quark stars if you removed the matter, it would remain at approximately the same density. Quark star matter is held together by the strong force and not gravity which results in a very different equation of state. A piece of quark star matter doesn't feel the strong force from the entire quark star, but only the immediately surrounding matter. They would have a nearly flat mass distribution as a function of radius and then an incredibly sharp edge.

At least that's for the case if the strange matter hypothesis that strange quark matter is actually the ground state of hadrons and normal matter is a metastable state. I'm not sure what would be the case if quark matter is only stable at high pressures and temperatures (I'd guess in that case it would decay into normal matter.)

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Re: A whimsical thought about Neutron Stars...and Quark Stars

Postby dylanhoen » Tue Oct 17, 2017 10:10 pm UTC

GOLD! It turns into gold, platinum, and some radioactive elements:
http://www.npr.org/sections/thetwo-way/ ... tron-stars
Back in 2012, after reading the baseball at the speed of light What-If, I posted a question about our periodic table and if there are stable nucleuses heavier than the ones we know about. I figured we might not be able to create them by smashing existing nucleuses together, but if 2 neutron stars side-swiped each other, and some matter managed to escape, would the neutronium turn back into atoms, and would some of them be heavier than what was on our periodic table, and relatively stable? I just read that article, and realized, I never checked for a what-if that answered my question, so I did a google search and found this forum post.
I also found this Island of stability page:
https://en.wikipedia.org/wiki/Island_of_stability

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Re: A whimsical thought about Neutron Stars...and Quark Star

Postby Eebster the Great » Wed Oct 18, 2017 4:10 am UTC

Tass wrote:I am fairly certain that is the answer too. An explosion of neutrons, subsequently decaying with their around 15 minutes half-life.

Minor detail: The neutrons will be moving extremely rapidly compared to an observer at rest with respect to the neutron star's center of mass, and therefore they will be heavily time-dilated from his frame of reference. Such an observer will see most of them survive an awful lot longer than 15 minutes.

(That's assuming these neutrons are sufficiently isolated from each other that other nuclear reactions don't occur, but since the density of a typical neutron star is substantially greater than that of any atomic nucleus, I expect all kinds of strange reactions to happen.)

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Re: A whimsical thought about Neutron Stars...and Quark Stars

Postby p1t1o » Wed Oct 18, 2017 10:56 am UTC

IIRC you dont get to neutronium until you get underneath the layer of iron which covers the surface. When compressing matter, iron is what you get just before you get neutronium. Its the bottom of the fusion ladder.

"Excavating" (ignoring all of the imaginary super-technology required) your teaspoon of neutronium, you would be gradually depressurising it as you pulled it out. By the time you extract it it will be iron again. A mountain-sized chunk of it.

Its only going to "explode" if you suddenly depressurise it, like if you teleported it out of the star. And as others have alluded, the explosion products would be a lot more complicated than hydrogen atoms.

Note that the expansion energy (whether gradual or explosive) is going to be roughly proportional to the energy you just used to drag it out of the star's gravity well, so its not like its going to be any use to you because you are already demonstrating the ability to manipulate those forces on a whim.

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Re: A whimsical thought about Neutron Stars...and Quark Stars

Postby Soupspoon » Wed Nov 08, 2017 10:15 pm UTC

Closely enough related to make this one of the possible places to post about a repeating supernova. Unless it deserves to be in the Lethal Neutrinos What-If, or just general news, or its own thread.


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