Zombie stars and dark energy

There’s a new kind of star in the skies… or at least a new name for some of them, reports Universe Today. They’re larger-than-usual Type Ia supernovas, more commonly called zombie stars – and they could reveal the secrets of dark energy:

For all intents and purposes, once they explode they’re dead… But it ain’t so. They might have a core of ash, but they come back to life by sucking matter from a companion star. Zombies? You bet.

“These stars are tools for measuring dark energy. They’re all about the same brightness, so we can use them to figure out distances in the universe,” [said Andy Howell, adjunct professor of physics at UCSB and staff scientist at Las Cumbres Observatory Global Telescope Network (LCOGT)]

“What we’ve found is that the universe hasn’t been expanding at the same rate,” said Howell. “And it hasn’t been slowing down as everyone thought it would be, due to gravity. Instead, it has been speeding up. There’s a force that counteracts gravity and we don’t know what it is. We call it dark energy.”

More on what Howell’s trying to figure out… and how backyard astronomers might help… at UC Santa Barbara’s press release.