The universe is full of awesome, destructive things that are awesome because they are far enough away. For instance, Stars explode. And when they explode, sometimes, they explode into pieces.

I honestly didn’t know that before today. I thought they just exploded into a cloud of gas and energy.

It turns out that sometimes when white dwarfs explode, they don’t explode completely.

A new paper in The Astrophysical Journal Letters, led by JJ Hermes, is titled (and I love this title) “8.9 hr Rotation in the Partly Burnt Runaway Stellar Remnant LP 40-365″. In this paper, researchers describe a literal partly burnt runaway stellar remnant.

White dwarfs are the leftover cores of stars like our Sun that have died. They exhale their atmospheres, and what is left collapses down into a dense blob of material that is no longer capable of having nuclear reactions. These aren’t entirely stable dense blobs. If you pile too much mass on them or if they gravitationally steal material off another star, they can end up with more material them they can structurally support, and things just go boom.

When one particular white dwarf did this, a chunk flew off, and that chunk is now called LP 40-365, and it was flung with enough speed that it is now on its way out of the galaxy with a colossal speed of two million miles per hour. This chunk isn’t massive enough to collapse back into a white dwarf and instead is a super weird star. As described by a student on this project, Odelia Putterman: To have gone through partial detonation and still survive is very cool and unique, and it’s only in the last few years that we’ve started to think this kind of star could exist.

Having found one weirdo high-speed shrapnel star, this team went looking for more, and they found them. And I can’t wait to hear more about this kind of high-speed object. As Hermes says: These are very weird stars, what we’re seeing are the by-products of violent nuclear reactions that happen when a star blows itself up.

More Information

Boston University press release

“8.9 hr Rotation in the Partly Burnt Runaway Stellar Remnant LP 40-365 (GD 492),” J. J. Hermes et al., 2021 June 7, The Astrophysical Journal Letters