Do 'time bomb' stars tick in the galaxy?

New research shows that some old stars might be held up by their rapid spins. When they slow down, they explode as supernovae. Thousands of these “time bombs” may be scattered throughout our galaxy.

“We haven’t found one of these ‘time bomb’ stars yet in the Milky Way, but this research suggests we’ve been looking for the wrong signs,” says Rosanne Di Stefano of the Harvard-Smithsonian Centre for Astrophysics.

The specific type of stellar explosion Di Stefano and her colleagues studied is called a Type Ia supernova.  It occurs when an old, compact star known as a white dwarf destabilizes, according to a Harvard-Smithsonian Centre statement.

A white dwarf is a stellar remnant that has ceased nuclear fusion. It typically can weigh up to 1.4 times as much as our Sun – a figure called the Chandrasekhar mass after the astronomer who first calculated it.

“Any heavier, and gravity overwhelms the forces supporting the white dwarf, compacting it and igniting runaway nuclear fusion that blows the star apart.  “We don’t know of any super-Chandrasekhar-mass white dwarfs in the Milky Way yet, but we’re looking forward to hunting them out,” said co-author Rasmus Voss of Radboud University Nijmegen, The Netherlands.