A rare quadruple star system could be heading towards a supernova, but in a way never seen before. The system, HD74438, is a double binary found by Gaia in 2017. Now, after years of follow up observations, the research team determined that the outer pair is disrupting the inner one’s orbit, making it increasingly elliptical.
The more elliptical the orbit becomes, the higher the chance that two of the stars might one day collide and merge. If they did so, they would cross what’s known as the Chandrasekhar limit, a mass 1.4 times greater than the Sun’s, above which all stars are destined to undergo a supernova.
“Interestingly, 70 to 85 per cent of all thermonuclear supernovae are now suspected to result from explosions of white dwarfs with sub-Chandrasekhar masses,” says Karen Pollard from the University of Canterbury in New Zealand. “As a result of mass transfer or mergers, these white dwarfs can explode as a thermonuclear supernova explosion.”
The discovery is just one way such transfer can happen, showing there could be many more routes to supernova waiting to be discovered. www.canterbury.ac.nz