Scientists help solve mystery of what causes exploding stars

This discovery gives weight to a theory that a white dwarf star devours material from its giant star companion until the white dwarf explodes as a supernova. Scientists from The Australian National University (ANU) and overseas have helped to solve the mystery of what causes exploding stars, which are used to measure the accelerating expansion of the Universe. The international study has found that a small star hurtling through our Galaxy is highly likely to be a piece of shrapnel from a huge explosion that happened millions of years ago. ANU Professor Lilia Ferrario said the explosion was a supernova event in a binary system where a super-dense white dwarf, a dead star that has run out of nuclear fuel, sucked mass away from its giant star companion. "What triggers these supernovae explosions is uncertain," said Professor Ferrario from the ANU Mathematical Sciences Institute, who is one of the authors of the study. "This discovery gives weight to a theory that a white dwarf star devours material from its giant star companion until the white dwarf explodes as a supernova." Professor Ferrario said the star the team studied is the remnant of an under-luminous type Ia supernova, a sub-class of supernovae that have a uniform brightness which makes them useful as standard candles to measure the expansion of the Universe. "The mass that accumulated on the white dwarf caused a thermonuclear runaway and a violent explosion that destroyed the binary system.