Neutron Stars...Do They Glow?

A few other threads on stars got me to wondering how a Neutron Star would glow. My grasp of physics is weak so be nice.

As I understand it light is made by electrons getting excited to higher states and then dropping back down again. When the electron drops into a lower state it emits a photon (light). Now here we have a Neutron Star where all the electrons are crammed into the nucleus of the atom. How is light produced from a soup of neutrons? Do the electrons pop out for a second to make light and then dive back in to the nucleus? I believe I’ve seen pictures of Pulsars (a unique form of Neutron Star) but I don’t know what wavelength the pictures were formed from (visible light, x-rays or whatever). Whatever the wavelength being viewed obviously a Neutron Star can emit energy…I’m just curious how it does it and whether it emits in the visible light spectrum as well.

As long as I’m on about Neutron Stars what is the final end for a Neutron Star? Do they behave like White Dwarfs in that they slowly cool over time till they disappear and all that’s left is a cold hunk of Neutronium (if such a thing as Neutronium even exists)? What else could happen to them? Do they ‘evaporate’ till enough stuff is gone that they explode? Any other ideas?

From what I’ve read, the outer layer of a neutron star is theorized to be covered with a shell of degenrate matter - highly compressed but still having individual atoms and free electrons, so still able to glow. Neutron stars are also supposed to have majorly strong magnetic fields. Don’t ask me how a solid ball of neutral particles maintains a magnetic field either.


I’m not sure if a neutron star glows uniformly or not, but I do know that the crust of a neutron star is primarily comprised of iron nuclei and electrons. In addition at the very surface of the star neutrons decay into protons and electrons and the electrons are accelerated to relativistic velocities by the intense magnetic fields and radiate via synchrotron radiation.

Keep in mind that electrically conducting fluids tend to trap magnetic field lines, and the core of a neutron star is a superconductor.

What generates the magnetic field of a neutron star ?

Here’s a lovely new picture of a neutron star, and a quark star glowing festively beside each other in the Grand Canyon of the Colorado. The accompanying article suggests that some neutron stars may convert into quark stars. That scenario is a big departure from the old standard line about neutron stars gradually cooling and losing spin until they are visually indetectable.

by Whack-a-Mole

It depends on its mass, but the ones with a solar mass of 3 or bigger (I believe it’s 3) eventually become black holes.

About the way neutron stars shine, there’s something called the “lighthouse effect” but I can’t remember exactly what it is, so you can do a search or someone more capable can describe it.

I’m still a bit unclear as to what exactly is happening inside a Neutron Star. I assume fusion is out of the question in the core. Does fusion occur in the crust?

Also, my question as to the end of a Neutron Star still has me puzzled. Keeping that much stuff crammed together would seem like it would generate intense amounts of heat. Still, I can’t imagine a Neutron Star constitutes a limitless source of energy. Sooner or later one would suspect that it’d have to cool off if it kept radiating energy. Yet again I find the notion of a cold Neutron Star odd as well. I realize that stars with a solar mass 3 times or more of our sun become black holes but I don’t think they become Neutron Stars (unless you count the Neutron Star phase it passes through quickly on its way to becoming a black hole).

Actually, that raises another question in my mind. Just how long (roughly) would it take a star destined to be a black hole to actually collapse into a black hole? Is it quick in our (human) terms, quick in stellar terms (e.g. 1,000 years) or slow all around (e.g. one billion years)?

I should clarify my earlier post: the neutron star with a solar mass of ~3 or larger before the star died will eventually turn into a black hole. My understanding is that this happens because the mass of the neutron star kind of collapses on it’s self and turns into black hole it can then turn into a singularity.

Don’t know about the other questions

If a star’s going to turn into a black hole, it’ll do so awfully close to instantly after fusion stops. If it settles down to a neutron star instead (or maybe a quark star) then it’ll stay that way indefinitely, unless something increases its mass (two colliding neutron stars, for instance, can form a black hole). Fusion is no longer occuring in the neutron star, and all the heat it has is residual and will eventually be lost. However, if some fresh new hydrogen or helium falls onto the surface, perhaps from a companion star in the red giant stage, it can fuse.

If you’re asking how long it will take for a “live” star to die and leave behind a hole, supermassive stars (i.e., the kind that form holes) can have a total lifespan of a few million years or shorter.

Yes, neutron stars glow. However, it may be pretty dim. Since neutron stars have a non-zero temperature, they should emit blackbody radiation. I have no idea what the mechanism would be, however.