How a star's mass decides its end: white dwarfs, neutron stars, and black holes

A star's mass on the main sequence decides how it will end. A low- or medium-mass star like the Sun swells into a red giant, gently sheds its outer layers as a glowing planetary nebula, and leaves behind its hot core as a white dwarf, an object about the size of Earth but so dense that a teaspoon of it would weigh tons on Earth. A star born with more than about 8 times the Sun's mass fuses heavier and heavier elements until it builds an iron core, which collapses and triggers a supernova explosion. What remains of the core becomes a neutron star, only about 20 kilometers across yet more massive than the Sun, packed as densely as an atomic nucleus; rapidly spinning neutron stars can appear as pulsars. If the leftover core is too massive, more than roughly 2 to 3 times the Sun's mass, nothing can stop its collapse, and it becomes a black hole, whose gravity is so strong that not even light can escape from inside its event horizon.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report