Conversion of the protons of star into neutrons with the emission of neutrinos
So-called supernova explosion occurs as a result of gravitational collapse of a star, completing its life cycle, if its weight exceeds a few solar masses (the Chandrasekhar limit). In proportion to the gravitational compression of star, the energy of electrons in the core of star rises and reaches a threshold value that allows to convert almost all its protons into neutrons, which is accompanied by the emission of neutrinos. Before leaving the star, the neutrinos interact with its substance for several seconds, which leads to the creation of antineutrinos and neutrinos of all generations with the typical energy of ten mega-electron-volts. They take away near 99% of the explosion energy, while the electromagnetic, including light, emission of the supernova falls of one percent of released energy, and kinetic energy of the ejection of star composes the rest.