Neutron star and white dwarf material

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Discussion Overview

The discussion centers on the consequences of removing material from neutron stars and white dwarfs, exploring the stability and potential explosive outcomes of such actions. Participants consider the nature of the material and the physical processes involved, including chemical and nuclear reactions, as well as the implications of electron degeneracy and pressure in white dwarfs.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that removing material from neutron stars or white dwarfs would lead to instability and potentially explosive outcomes.
  • One participant proposes that the outer crust of a neutron star is composed mostly of ions and electrons, expecting that the matter would revert to normal atoms, resulting in a large chemical explosion.
  • Another participant speculates that the crust of a neutron star might be iron and suggests the outcome could be more akin to a nuclear explosion.
  • A participant questions the reasoning behind expecting a nuclear explosion from the removal of surface material.
  • There is a discussion about the high kinetic energy of electrons in white dwarfs and how the removal of pressure might lead to a violent expansion and energy release.
  • One participant posits that neutron decay could occur upon the removal of extreme pressure from neutron star material.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the explosions that might occur, with some favoring chemical reactions and others suggesting nuclear processes. The discussion remains unresolved regarding the specific outcomes of removing material from these stellar objects.

Contextual Notes

Participants reference complex physical principles such as electron degeneracy pressure, the Pauli exclusion principle, and the uncertainty principle, indicating a reliance on these concepts to support their claims. There is uncertainty about the exact nature of the material and the processes that would occur upon removal.

mathman
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Neutron stars are held together by extremely strong gravitational force. What would happen to a chunk of the star if it had been removed and left to stand alone?

Same question for a chunk of a white dwarf?
 
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Either would be unstable once removed from the gravitational well. 'Boom' is probably the word I'm looking for.
 
Chronos said:
'Boom' is probably the word I'm looking for.

:smile:
 
mathman said:
Neutron stars are held together by extremely strong gravitational force. What would happen to a chunk of the star if it had been removed and left to stand alone?

Same question for a chunk of a white dwarf?

The outer crust of a Neutron star is thought to be composed of mostly ions and electrons, not neutrons. I expect that the matter would no longer be degenerate and would quickly form normal atoms again. Since atoms release energy when electrons bind with nuclei, I would expect a very large chemical explosion. Same thing for a white dwarf.
 
The crust of a neutron star is probably iron, as I recall. And I believe the result would be more on the order of a nuclear explosion - just my guess. I would hate to have the job of mining material from either object. The scoop design would be problematic and the workmans comp insurance premiums - priceless.
 
Why do you think there would be a nuclear explosion from the removal of surface material?
 
Chemical processes do not occur at these energy levels.
 
If the nuclei are stable then what kind of nuclear processes are we talking about here?
 
To rephrase my question slightly. Assume we could get material from deep in the interior of the neutron star or white dwarf. What happens?
 
  • #10
Without being educated in this area I can only guess, but I'd say probably some kind of explosion. I know in a white dwarf that many of the electrons have high kinetic energy. From wikipedia:

This state of the electrons, called degenerate, meant that a white dwarf could cool to zero temperature and still possesses high energy. Another way of deriving this result is by use of the uncertainty principle: the high density of electrons in a white dwarf means that their positions are relatively localized, creating a corresponding uncertainty in their momenta. This means that some electrons must have high momentum and hence high kinetic energy.[38][40]

Compression of a white dwarf will increase the number of electrons in a given volume. Applying either the Pauli exclusion principle or the uncertainty principle, we can see that this will increase the kinetic energy of the electrons, causing pressure.[38][41] This electron degeneracy pressure is what supports a white dwarf against gravitational collapse. It depends only on density and not on temperature. Degenerate matter is relatively compressible; this means that the density of a high-mass white dwarf is so much greater than that of a low-mass white dwarf that the radius of a white dwarf decreases as its mass increases.[1]

I assume that the removal of pressure from the material would result in a great release of energy as the matter violently expands and high energy electrons run into other particles.

As for neutron stars I would expect something similar in addition to neutron decay once the extreme pressure is removed.
 

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