What is a Pair-Instability Supernova?

When an unstable pair of supernovas occurs when positron-positron pairs are generated, free electrons and positrons are produced under the collision of atomic nuclei and high-energy gamma rays, reducing the thermal pressure generated inside the supergiant core. This weakening of pressure causes a local collapse, and then a large number of rapid combustions cause a thermally imbalanced thermonuclear explosion that completely blows the stars apart without leaving the remains of a black hole.