What leads to the formation of neutron stars?

Neutron stars are formed as a result of the gravitational collapse of a massive star after a supernova explosion.

A neutron star is the collapsed core of a large star, typically having a mass between 1.4 and 3 solar masses. Stars are fuelled by nuclear fusion in their cores, where lighter elements combine to form heavier ones, releasing energy in the process. However, once a star has exhausted its nuclear fuel, it can no longer support its own weight and begins to collapse under its own gravity.

This collapse triggers a supernova, a powerful explosion that disperses the outer layers of the star into space. The core of the star, however, continues to collapse. If the core's mass is between about 1.4 and 3 times the mass of the sun, the collapse is halted by a quantum mechanical effect known as neutron degeneracy pressure. This results in the formation of a neutron star.

Neutron stars are incredibly dense, with a teaspoon of neutron star material weighing about a billion tonnes. They are composed almost entirely of neutrons, subatomic particles with no electric charge. This is because the intense pressure of the collapsing star forces protons and electrons to combine to form neutrons.

The formation of a neutron star is a fascinating example of the life cycle of stars and the extreme conditions that can exist in the universe. It's a testament to the power of gravity and the intriguing properties of matter under extreme pressure.