Has the merger of a neutron star and an anti-neutron star been modeled?

In summary, when neutron stars and anti neutron stars collide, they may partially annihilate with some stars pushed away from each other.
  • #1
Cato
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What would happen if a neutron star and an antineutron star collided
If a neutron star and an anti neutron star collided, would they 1) completely annihilate each other, 2) form a black hole, or 3) partially annihilate each other with the remaining stars being pushed away from each other by the energy created?
 
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  • #2
None of those options are mutually exclusive. Often we think of annihilation as two particles interacting with each other and turning into photons (so-called 'pure energy', which is more like two particles turning into two other particles). The reality is much more complicated though, especially when you get into composite particles and high-mass particles.

Protons and neutrons (and their anti- particles) often generate a shower of pions, which themselves decay into neutrinos, photons, and muons. Beyond the possible interactions and decays of pairs or single particles, the environment in a neutron star-antineutron star annihilation would be so energetic that you'd likely generate all kinds of different particles. I'd expect a portion of the stellar material to be blasted into space along with some of this newly created matter.

So there's not really a difference between a partial and a complete annihilation, as both can leave large amounts of matter behind.

As for option 2, this can happen regardless of the annihilation process. At least some portion of the annihilation and explosion could occur inside of the event horizon formed by the merger of the two stars.
 
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  • #3
I'd add that I don't know that I'd expect a unique answer. A direct head-on collision is likely quite a different thing from a grazing impact.

I'd also add that I doubt that anyone's modelled this because as far as I know the equations of state in the interior of neutron stars are not known with any real certainty, and they'd matter a lot here.
 
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  • #4
Probably nobody has spent any effort doing this because it is highly unlikely that an anti-neutron star exists in our universe.
 
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  • #5
Correct...I was thinking of "complete annihilation" as leaving behind only photons -- that was mistaken. Yes, Ibix, I could imagine a grazing impact -- at what? more than half the speed of light? -- producing something very different from a head on collision. Would be something to see. Thanks for the answers.
 

1. What is a neutron star and an anti-neutron star?

A neutron star is a type of compact star that is formed when a massive star goes supernova. It is incredibly dense, with a mass greater than that of the sun packed into a sphere with a diameter of only about 10 kilometers. An anti-neutron star is a hypothetical type of star made up of anti-matter particles, including anti-neutrons.

2. What is a merger of a neutron star and an anti-neutron star?

A merger of a neutron star and an anti-neutron star would occur when these two types of stars collide and combine, resulting in a larger and more massive object.

3. Why is the merger of a neutron star and an anti-neutron star important to study?

Studying the merger of a neutron star and an anti-neutron star can provide valuable insights into the behavior of matter and anti-matter in extreme environments, as well as the formation and evolution of compact objects in the universe.

4. Has the merger of a neutron star and an anti-neutron star been observed?

To date, the merger of a neutron star and an anti-neutron star has not been observed or confirmed. However, it is a topic of ongoing research and there have been some theoretical models and simulations of this event.

5. What are some potential outcomes of a neutron star and anti-neutron star merger?

Some potential outcomes of a merger between a neutron star and an anti-neutron star could include the formation of a black hole, the production of high-energy radiation, and the creation of heavy elements through nucleosynthesis processes.

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