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Degeneracy pressure and stellar collapse

  1. Mar 3, 2016 #1
    I have a question.
    In a massive star (more than say 5 times the mass of the sun), the electron/neutron degeneracy pressure is unable to prevent the gravitational collapse. Does this imply that the Pauli's exclusion principle breaks down and two or more electrons/neutrons collapse to the same quamtum state?
  2. jcsd
  3. Mar 3, 2016 #2


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    It does not break down. The collapse releases more energy than necessary to put the particles into higher states. That is exactly the condition for a collapse to happen.
    Once a black hole forms, we don't know what happens inside (where general relativity predicts a singularity) - that would need a theory of quantum gravity. What happens outside is well understood.
  4. Mar 4, 2016 #3

    Ken G

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    There are two paths by which a core might exceed the roughly 3 solar masses needed to collapse into a black hole. One is, it can amass more than 3 solar masses while it is still an ideal gas. In this case, the Pauli exclusion principle plays no role at all, the collapse will occur before it even matters that there is a Pauli exclusion principle. Or, the core can go degenerate while below 3 solar masses, and then it collapses into a black hole when the neutron star has more degenerate mass added to it and reaches 3 solar masses or so, degenerate all the while. So there really isn't a scenario like you are asking about, where it matters that there even is a PEP, and the mass is above 3 solar masses.
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