By Ron Cowen
Although they can’t fully explain why a star blows up, astronomers thought that they had accurately determined the maximum mass that a star could have before exploding as a common type of supernova. Now, they’ve found a star that breaks the rule.
According to prevailing theory, a type 1a supernova is triggered by a compact star called a white dwarf piling up matter stolen from a bloated companion star. When the white dwarf becomes as heavy as 1.4 times the mass of the sun, the high density and heat generated by the matter spark a thermonuclear explosion.