Although the outer planet is probably a gas giant slightly larger than Uranus and therefore not suitable for life as we know it, these findings do show that circumbinary planets can and do exist in habitable zones.
"The thing I find most exciting is the potential for habitability in a circumbinary system," said study co-author William Welsh at San Diego State University. "Kepler-47c is not likely to harbor life, but if it had large moons, those would be very interesting worlds."
Weird weather on Tatooine planets
Circumbinary planets might undergo relatively wild climate swings.
On Earth, the sun is a relatively stable source of light, with the solar insolation or energy we receive only varying by 0.1 percent or so. "As a result, we don't need to worry about what the sun is doing, at least over time-scales of years to decades," Orosz said. "For a planet around a binary system, there can be changes in the insolation of several percent on the time-scale of days to weeks. In addition, if the planet's rotation axis is tilted, then that also has an effect. Therefore the seasons are rapid and complicated."