hi! I was wondering what is the difference between white dwarfs and neutron stars? Oh and, since neutrons stars are called STARS, does that mean that they produce light? If yes, then how? Aren't they made of 100% neutrons?
Put simply, neutron stars are like white dwarfs on steroids. A white dwarf is the “corpse” of a low mass star, like our own Sun. They are usually about the size of a planet, and are incredibly dense. They are almost entirely composed of carbon and oxygen, and are only supported by “electron degeneracy pressure”, which essentially means that the electrons in atoms refuse to get any closer to each other. Since they have no fuel, they only give off light because they are very hot when they are created. They will eventually cool off, and turn into a brown dwarf.
Neutron stars are similar, but are created by the collapse of a much more massive star than our own. Here, the gravity is so strong, not even electron degeneracy pressure can hold the star under its own weight. So, all the electrons fuse with protons to create neutrons (hence the name), and are now supported by neutron degeneracy pressure. These are often much denser and smaller than white dwarfs, being about the size of a city. Like white dwarfs, though, they have no fuel left to spend, and give off light as a result of thermal radiation. As long as they remain isolated, they will eventually cool down and stop giving off light. Thanks for asking!