For the first time, astronomers have detected two planets in stable orbits about a binary star system, suggesting that binary stars could have complex planetary systems much like our own. One of the planets in the so-called circumbinary system exists in what astronomers call the habitable zone — a region where water would remain liquid and thus could support life. The planet itself is Uranus-sized, however, and is thus most likely a gas giant. But if it has a large moon, that moon could conceivably support life.
The system was discovered by NASA’s Kepler mission, which continually scans a portion of the sky searching for exoplanets — planets orbiting distant stars — and binary star systems. The objects are revealed when they pass between a star and the Earth, causing the star’s light to dim briefly. So far, Kepler has detected more than 2,300 candidate exoplanets and 2,100 binary stars. Four of those binary systems have been found to have a single planet.