WHY STARS EXPLODE OR QUIETLY FADE AWAY?
Stars are born and they die. When a star uses up all its fuel which is in the form of hydrogen, it no longer releases energy. Gravitational forces take over and the star slowly collapses inwards. In the end the star may fade out quietly to become a white dwarf or it may explode.
Whether a star collapses or explodes depends on its mass. If it is a heavyweight star which means if it is more than about 1.4 times the mass of our sun, it becomes unstable and explodes to become a very bright star called supernova. If it is less massive it shrinks into a white dwarf.
The critical mass of 1.4 suns is known as the Chandrasekhar limit. This limiting factor was predicted in the 1930s by the Indian-American astrophysicist Subrahmanyan Chandrasekhar.
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