‘Black Widow’ Binary Star Found — Shortest Orbit Ever

Black widow binary stars consist of a neutron star consuming a nearby companion star. Find out how scientists used a new technique to find one of these rare systems, and why their discovery has two other unique characteristics.

Like most people in the northern hemisphere, the first constellation I learned to recognize was the Big Dipper. Forgive me, the Big Dipper is technically an asterism, being only part of Ursa Major, the Great Bear.

Anyway, when I started using a telescope for stargazing, I started looking for double stars to try to split, and the first place I looked was the familiar Big Dipper in the northern sky. There’s a pair of stars in its handle called Mizar and Alcor.

We now know that Mizar and Alcor are part of a larger array of stars called the Ursa Major Moving Group. It’s not yet clear to astronomy if gravity holds the group together.

Distinction — Double Stars Versus Binary Stars

That’s an important distinction astronomers make. There are double stars that just happen to appear close together in the sky, and binary stars that revolve around a shared…