Kepler-22b is an extrasolar planet orbiting G-type star Kepler-22. It is located 600 light years away from Earth in the constellation of Cygnus. It was discovered by NASA's Kepler Space Telescope and is the first known transiting planet to orbit within the habitable zone of a Sun-like star
Kepler-22b's radius is roughly 2.4 times the radius of Earth. Its mass and surface composition remain unknown, with only some very rough estimates established: It has less than 124 Earth masses at the 3 sigma confidence limit, and less than 36 Earth masses at 1 sigma confidence.