Why isnt the universe full of quark stars?

In summary, there is no strong evidence to support the existence of quark stars. The theoretical motivation is weak, and we have no observational evidence in support of their existence.
  • #1
Mustang11
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Hi all. I am curious as to why quark stars have not dominated by now, given their inability to decay as they are a mass of fundamental particles. What prevents this?
 
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  • #2
They probably don't exist. The theoretical motivation is weak, and we have no observational evidence in support of their existence.
 
  • #3
What is the distinction between a quark star and a neutron star? Neutrons are made of quarks.
 
  • #4
mathman said:
What is the distinction between a quark star and a neutron star? Neutrons are made of quarks.
I gather that a hypothetical quark star would consist of disassociated quarks instead of triplets composing neutrons.
However I also gather that the existence free quarks in this manner is inconsistent with several well accepted theories.
 
  • #5
mathman said:
What is the distinction between a quark star and a neutron star? Neutrons are made of quarks.
As rootone stated, the form of matter is different. Instead of just a bunch of neutrons, it'd be sort of like a single giant nucleon consisting of huge numbers of quarks. It would be a hypothetical intermediate stage between a neutron star and a black hole.

However, if this form of matter does exist, it is predicted that it would actually be more stable than any other matter, so that any matter which came in contact with the quark star stuff would become quark star stuff. Thus, if we had a quark star implode (to become a black hole after collecting too much matter), and some of the material of that quark star escaped, then it would convert anything it came into contact with.

I think this is a pretty good reason to believe that quark stars don't exist.
 
  • #6
Quark stars and quark matter are hypothetical, but I'm unaware of any strong objections to the possibility that they could exist. Quark matter would exist at extremely high temperatures and pressure, where the quarks are asymptotically free, so there is no reason for them to assemble into neutrons. It would be like shoving a huge amount of quark-gluon plasma into a small volume. If some quark matter were ejected from the implosion of a quark star, the ejected components would not necessarily be at the pressure required to remain quark matter and would probably stablize as ordinary matter.
 
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  • #7
If they did exist though they would probably be pretty much invisible to us, at least with any instrumentation we presently have.
Black holes may indeed be more easily detected through their indirect effects than quark stars would be.
Maybe there is some hope yet for massive compact halo objects being the explanation of dark matter.
*mods* - This is not a personal theory, please set your phasers on stun only.
 
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  • #8
fzero said:
Quark stars and quark matter are hypothetical, but I'm unaware of any strong objections to the possibility that they could exist. Quark matter would exist at extremely high temperatures and pressure, where the quarks are asymptotically free, so there is no reason for them to assemble into neutrons. It would be like shoving a huge amount of quark-gluon plasma into a small volume. If some quark matter were ejected from the implosion of a quark star, the ejected components would not necessarily be at the pressure required to remain quark matter and would probably stablize as ordinary matter.
According to the models, quark matter is more stable at any pressure.
 
  • #9
Chalnoth said:
According to the models, quark matter is more stable at any pressure.

But at low temperatures, quarks are not asymptotically free; wouldn't they form hadrons? Certainly that happens to quarks inside accelerators like the LHC when they are ejected from collisions--that's how quarks are spotted, by the hadron jets they produce.
 
  • #10
Chalnoth said:
According to the models, quark matter is more stable at any pressure.

I would tend to side with PeterDonis, that the ejected matter would be like jets. I am not doubting your statement about the pressure, but could you suggest an up-to-date reference on the equation of state? I'm sure some progress has been made since I've read anything about it.
 
  • #11
PeterDonis said:
But at low temperatures, quarks are not asymptotically free; wouldn't they form hadrons? Certainly that happens to quarks inside accelerators like the LHC when they are ejected from collisions--that's how quarks are spotted, by the hadron jets they produce.
Here's a review:
http://arxiv.org/abs/astro-ph/0407155

See the section on strange quark matter in particular. The speculation is that because of the extra degree of freedom from the strange quark, this would be the true ground state of strong interactions. I don't think it's a very likely possibility, but it is fun to think about.
 

Related to Why isnt the universe full of quark stars?

1. Why do we not see more quark stars in the universe?

Quark stars are thought to be extremely rare in the universe because they are only formed through very specific and rare conditions. They require a specific range of mass and density in order to undergo a process called quark deconfinement, where the protons and neutrons in the core of a neutron star break down into their constituent quarks. This process is only possible in the extreme conditions found in the core of a neutron star, and not all neutron stars have the right mass and density to undergo this transformation.

2. Can we detect quark stars in the universe?

Currently, there is no confirmed detection of a quark star in the universe. This is because they are extremely small and dense, making them difficult to detect even with advanced telescopes. However, there have been some observations that suggest the existence of quark stars, such as the rapid rotation of some neutron stars, which could be explained by the formation of a quark star.

3. How do quark stars differ from neutron stars?

Quark stars and neutron stars are both extremely dense and compact objects that are formed from the remnants of a supernova explosion. However, quark stars are thought to be even denser than neutron stars, as they are made up of quarks instead of just neutrons. Quark stars also have a much smaller radius than neutron stars, making them even more difficult to detect.

4. Could a quark star support life?

It is highly unlikely that a quark star could support life as we know it. Due to their high density and extreme conditions, the surface of a quark star would be highly unstable and inhospitable. Additionally, the intense radiation and magnetic fields surrounding a quark star would make it impossible for any form of life to survive.

5. Are there any potential benefits to studying quark stars?

Despite the challenges in detecting and studying quark stars, they are still valuable objects for research. Studying quark stars can provide insight into the fundamental properties of matter and the extreme conditions that exist in the cores of these objects. This knowledge can also help us better understand neutron stars and other compact objects in the universe.

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