Kepler-47 planetary system. Illustration of two of the gas giant planets in the Kepler-47 binary star system. The binary stars are at lower right (white and orange). At bottom right is the planet Kepler-47b (blue). At upper left is the planet Kepler-47c (slightly larger than Neptune), which orbits in the system's habitable zone. Kepler-47c orbits every 303 days, while Kepler-47b orbits in less than 50 days. These planets are circumbinary, orbiting both stars. The larger of the two binary stars is similar in size to the Sun. This planetary system is 4900 light years from Earth, in the constellation of Cygnus. It was discovered in 2012 by NASA's Kepler space telescope.