The outer world, Kepler-47c, lies within the so-called “habitable zone,” where temperatures could support liquid water on the surface, provided it had a surface. Astronomers suspect Kepler-47c is a gas giant, slightly bigger than Neptune. But it could have life-friendlier moons.

Kepler scientists previously discovered four systems each having two stars and one planet. The discovery of multiple planets in a dual-star system taxes currently held theories about how planets form.

“The multi-planet nature of the Kepler-47 system establishes that despite the chaotic environment around binary stars, planetary systems can form and persist close to the binary,” Orosz wrote.