Kepler-16b was the first unambiguous confirmed planet known to orbit two stars. It is a circumbinary planet, meaning its orbit surrounds both members of the Kepler-16 binary system rather than circling just one star.
The planet was announced in 2011 after NASA’s Kepler spacecraft detected transits: tiny dips in starlight as Kepler-16b crossed first one star and then the other. The system’s two stars are a larger K-type star and a smaller M-type red dwarf. They orbit each other every roughly 41 days, while the planet takes about 229 days to circle their shared center of mass.
Kepler-16b is often nicknamed “Tatooine” because its two-star sky resembles the fictional Star Wars world. A common mix-up is to count the binary stars as one host star, but the defining feature of a circumbinary orbit is that the planet travels around both. It is also a Saturn-mass gas giant, not an Earth-like rocky world, and its orbit lies well beyond the stars’ own orbit.