* For stars less massive than about 8 solar masses: The core becomes a white dwarf, a small, dense, and extremely hot object composed mainly of carbon and oxygen. White dwarfs no longer undergo nuclear fusion, but they slowly cool down over billions of years.
* For stars between about 8 and 20 solar masses: The core collapses into a neutron star, a superdense object where electrons and protons are squeezed together to form neutrons. Neutron stars are incredibly dense, with a teaspoonful weighing billions of tons. They also spin rapidly and have intense magnetic fields.
* For stars more massive than about 20 solar masses: The core collapses so violently that it forms a black hole, an object with such intense gravity that not even light can escape. Black holes are surrounded by an event horizon, a boundary beyond which nothing can escape.
Note: The specific type of remnant also depends on other factors like the star's rotation rate and the presence of a companion star.
