Astronomers Discover Baby Supernovae

This new type of mini-supernova doesn’t destroy the star

In a type Ia supernova
In a type Ia supernova, and the new Iax mini-supernova, a white dwarf star (the one with the disk) eats a nearby star. When it grows big enough, it explodes. Lawrence Berkeley National Laboratory

Supernovae are the parents of the universe, the scatterers of the star stuff that make us all (as Carl Sagan so famously described). But now, new research led by the Harvard-Smithsonian Center for Astrophysics’ Ryan Foley describes the discovery of a new kind of miniature supernova, one that leaves the exploding star “battered and bruised, but it might live to see another day,” said Foley to Charles Choi for

“We’re not quite sure why only part of the star might get destroyed. That’s a tough problem we’re working on right now.”

The new type of partial supernova happens in much the same way as one class of regular, full-blown supernovae. A white dwarf star in a two-star system, says Choi, sucks material off of its partner. When the white dwarf consumes too much of its partner’s mass, it explodes (this is called a Ia supernova). In the new type of mini-supernova (a Iax supernova), the white dwarf’s partner star is missing its outer layer. The white dwarf star still steadily consumes its stellar neighbor, but something is different (and scientists aren’t quite sure why, exactly, this matters.)

The end result: a small supernova, some shining just 1% as bright as their full-sized brethren.

“Type Iax supernovas aren’t rare, they’re just faint,” Foley said. “For more than a thousand years, humans have been observing supernovas. This whole time, this new class has been hiding in the shadows.”

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