How do neutron stars get their energy?

Question

Neutron stars are amazing. They are the matter at its extremest state.

But, how do they get their energy? Do they convert the neutrons into energy? Or is this just energy stored from the supernova of the big star that the neutron star came from?

They have to have a source of energy somehow, otherwise, you wouldn't get things like magnetars.

Answer 1

Much of the energy in neutron stars comes from their spin, which is just left over from the formation of the neutron star. When the dense neutron core is formed from a much larger giant star, the contraction to small size while conserving angular momentum can result in the surface of the star travelling at a large fraction of the speed of light. Many neutron star phenomena, such as pulsars, are simply powered by the slow spin-down of this residual angular momentum.

Additional energy can come from material accreting onto the surface. The gravitational field is so strong, that gas falling in from a large distance is going at a large fraction of the speed of light when it hits the solid surface of the neutron star. The impact releases a lot of energy. Also, that material may accumulate as a crust of normal matter on the surface. When this crust gets thick enough, it can suddenly ignite into a runaway nuclear fusion reaction, and burn to heavier elements in a few seconds or minutes. This creates an x-ray burst.

The neutron material itself is pretty much a dead-end as far as energy release is concerned. The only way it can release more energy is when enough mass is added to the neutron star to make it unstable and collapse to a black hole. This, however, makes quite a bang.

Answer 2

X-ray Observatory). The stars that eventually become neutron stars are thought to start out with about 8 to 20-30 times the mass of our sun. These numbers are probably going to change as supernova simulations become more precise, but it appears that for initial masses much less than 8 solar masses the star becomes a white dwarf, whereas for initial masses a lot higher than 20-30 solar masses you get a black hole instead (this may have happened with Supernova 1987A, although detection of neutrinos in the first few seconds of the supernova suggests that at least initially it was a neutron star). In any case, the basic idea is that when the central part of the star fuses its way to iron, it can't go any farther because at low pressures iron 56 has the highest binding energy per nucleon of any element, so fusion or fission of iron 56 requires an energy input. Thus, the iron core just accumulates until it gets to about 1.4 solar masses (the "Chandrasekhar mass"), at which point the electron degeneracy pressure that had been supporting it against gravity gives up the ghost and collapses inward.
At the very high pressures involved in this collapse, it is energetically favorable to combine protons and electrons to form neutrons plus neutrinos. The neutrinos escape after scattering a bit and helping the supernova happen, and the neutrons settle down to become a neutron star, with neutron degeneracy managing to oppose gravity. Since the supernova rate is around 1 per 30 years, and because most supernovae probably make neutron stars instead of black holes, in the 10 billion year lifetime of the galaxy there have probably been 10^8 to 10^9 neutron stars formed. One other way, maybe, of forming neutron stars is to have a white dwarf accrete enough mass to push over the Chandrasekhar mass, causing a collapse. This is speculative, though, so I won't talk about it
''Well You Asked''

Answer 3

There is no energy being generated within a neutron star. They inherit their heat, spin, and magnetic field from the star that collapsed to form them, with the gravitational collapse itself adding some more energy. The values of all these quantities become extremely high, as the heat, magnetic field, and angular momentum of a massive star get concentrated in a sphere of degenerate matter maybe 20 miles in diameter. Neutron stars are radiating away the energy of their parent star and will eventually go cold. The magnetic field of a magnetar is thought to last only a few thousand years. In some neutron stars, additional energy is released by matter orbiting around and falling onto the object.

Answer 4

Hi. If you imagine normal matter as a form of Styrofoam then a neutron (when a proton gets squeezed into its orbiting electron) you can think of as a tiny BB. There is no repulsion due to electrical forces so they can be in intimate contact. Most of their energy comes from the conservation of angular momentum.

Answer 5

The Pointer Sisters

Answer 6

Neutron stars get their energy by doing The Neutron Dance.

Duh. "I'm just burning, doing the neutron dance."

And uh we thank you.