Type Ia Supernovae

Not all supernovae come from massive stars. Type Ia supernovae occur when a white dwarf in a binary system accumulates mass from a companion star until it hits the Chandrasekhar limit of 1.4 solar masses. The entire white dwarf detonates in a thermonuclear explosion, leaving nothing behind.

Type Ia supernovae are crucial to cosmology because they all explode at nearly the same brightness, making them standard candles for measuring cosmic distances. It was Type Ia supernovae that revealed the expansion of the universe is accelerating — a discovery that earned the 2011 Nobel Prize in Physics.