What physically supports a white dwarf against gravitational collapse?

electron degeneracy pressure

A white dwarf represents the final evolutionary stage for many stars, having completely ceased nuclear fusion in its core. Therefore, it cannot rely on the outward thermal pressure generated by fusion reactions to counteract the immense force of gravity trying to crush the star inward. Instead, these incredibly dense stellar remnants are supported by a quantum mechanical phenomenon known as electron degeneracy pressure. This pressure arises because the Pauli exclusion principle prevents electrons from occupying the same quantum state, effectively resisting further compression once the star reaches this extremely compact state. The light and heat observed from a white dwarf are solely residual energy escaping from this highly compressed core.