What term describes a planet that orbits two stars?

A circumbinary planet is a planet that orbits two stars. The stars themselves form a binary system, and the planet travels around both of them rather than remaining gravitationally bound to just one.

The planet’s path usually lies farther out than the stars’ mutual orbit. From the planet’s perspective, the two stars circle one another while their combined gravity governs the planet’s larger orbit. This arrangement inspired the “Tatooine” comparison after the fictional world in Star Wars, which has two suns.

Kepler-16b, announced in 2011, was the first unambiguous circumbinary planet discovered. Its discovery showed that planets can form and remain stable around binary stars, despite the changing gravitational environment. Some circumbinary planets can also transit both stars, producing unusually complex patterns of dips in brightness.

Do not confuse “circumbinary” with a planet in a binary-star system that orbits only one member. That arrangement is called a circumstellar orbit. “Hot Jupiter” describes a planet’s size and close-in orbit, “super-Earth” describes a mass-size category, and “rogue planet” describes a world not gravitationally bound to a star.