Question-can a neutron star shed mass?

In summary, when a neutron star is "new", it loses a lot of its neutrinos by a process called deleptonization. This process lasts for about 100 to 1 million years, but after the protoneutron star stage, neutrino emissions dominate.
  • #1
Duane M
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Question--can a neutron star shed mass?

Once the steller core of a massive star collapses into a neutron star, is there any known mechanism by which the neutron star can shed mass?
 
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  • #2
Duane M said:
Once the steller core of a massive star collapses into a neutron star, is there any known mechanism by which the neutron star can shed mass?
Yes. When a neutron star is "new" with temperatures above ~ 109 K, there is strong heat-loss (therefore mass) by neutrino emission. At lower temperatures, there is "standard thermal photon cooling", which has a power proportional to T4 K. Another process is where an electron passes by a nucleus and, instead of emitting a single photon emits a neutrino-antineutrino pair. This has a power of about T6.

Either way, the heat loss translates to mass loss by emission of various particle types. There are more complicated processes which involve interaction of the (huge) magnetic field, but the bottom line is that any heat loss will also lead to a mass loss.
 
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  • #3
Yes. When a neutron star is "new"...
By "new" I think that you mean when is exactly what is called a protoneutron star. Then yes, it loses all its neutrinos by a process called deleptonization
 
  • #4
meteor said:
By "new" I think that you mean when is exactly what is called a protoneutron star. Then yes, it loses all its neutrinos by a process called deleptonization
Even after the protoneutron star (PNS) stage, neutrino emissions dominate for ~100 years in the "standard" model and as much as 1 million years in certain cases depending on the state of the "superfluidity" of the degenerate matter.

100 to 1 million years certainly extends well beyond the PNS stage. Deleptonization is a description of the change in properties of the matter in a neutron star, neutron loss is called neutron diffusion. See at least pages 1-4 (out of 61) at:

http://arxiv.org/PS_cache/astro-ph/pdf/0012/0012136.pdf [Broken]
 
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1. How does a neutron star shed mass?

A neutron star can shed mass through a process called accretion, where it pulls in material from a nearby companion star. This material is then heated to extremely high temperatures and emitted as X-rays, causing the neutron star to lose mass.

2. Can a neutron star lose mass naturally?

Yes, a neutron star can also lose mass through a natural process called pulsar wind. This occurs when the fast-spinning neutron star emits a powerful beam of energy and particles, which carries away some of its mass.

3. What happens to the mass that is shed by a neutron star?

The mass that is shed by a neutron star is converted into energy, according to Einstein's famous equation E=mc^2. This energy is then emitted as radiation, such as X-rays or pulsar wind.

4. Is the mass loss of a neutron star significant?

Yes, the mass loss of a neutron star can be significant over time. Depending on the rate of accretion or pulsar wind, a neutron star can lose a considerable amount of mass, which can affect its overall structure and properties.

5. Can a neutron star eventually lose all of its mass?

No, a neutron star cannot lose all of its mass. It has a lower limit of mass, known as the Tolman-Oppenheimer-Volkoff limit, which is approximately 1.4 times the mass of our Sun. This is because the neutron star's gravity is strong enough to prevent any further mass loss beyond this point.

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