Question

What is the maximum mass, expressed in solar masses, that a white dwarf can reach before it must collapse under its own gravity, according to the Chandrasekhar limit?

Accepted Answer

The Chandrasekhar limit is approximately 1.44 solar masses. This value represents the maximum mass a stable white dwarf star can support before its internal pressure can no longer counter the inward pull of gravity. A white dwarf is the remnant of a low-to-medium mass star that has exhausted its nuclear fuel and collapsed into a dense, Earth-sized object. Within this star, the primary force preventing further collapse is electron degeneracy pressure, a quantum mechanical effect arising from the Pauli exclusion principle, which dictates that no two electrons can occupy the same quantum state simultaneously. As mass is added to a white dwarf, the electrons are forced into higher energy states to satisfy this principle, causing the star to shrink and become denser. Once the mass reaches 1.44 solar masses, the electrons are moving at velocities approaching the speed of light, making them ultra-relativistic. At this threshold, the electron degeneracy pressure becomes insufficient to counteract gravity, causing the star to collapse, typically triggering a Type Ia supernova or resulting in the formation of a neutron star.

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What is the maximum mass, expressed in solar masses, that a white dwarf can reach before it must collapse under its own gravity, according to the Chandrasekhar limit?