Mass, radius, and temperature Kepler-22b's
radius was initially thought to be 2.4 times that of
Earth, but has since been revised to . it is thus likely to have a more
volatile-rich composition with a liquid or gaseous outer shell; this would make it similar to
Kepler-11f, one of the smallest known gas planets.
Natalie Batalha, one of the scientists on the Kepler Space Telescope project, has speculated, "If it is mostly ocean with a small rocky core, it's not beyond the realm of possibility that life could exist in such an ocean". This possibility has spurred
SETI to perform research on top candidates for
extraterrestrial life. In the absence of an atmosphere, its
equilibrium temperature (assuming an Earth-like
albedo) would be approximately , compared with Earth's . The star is about 4 billion years old. In comparison, the Sun is 4.6 billion years old. The
apparent magnitude of Kepler-22 is 11.5, which means it is too dim to be seen with the naked eye.
Orbit The only parameters of the planet's
orbit that are currently available are its
orbital period, which is about , and its
inclination, which is approximately 90°. From Earth, the planet appears to make a transit across the disk of its host star. In order to obtain further information about the details of the planet's orbit, other methods of planetary detection, such as the radial velocity method, need to be used. While such methods have been performed on the planet since its discovery, these methods have not yet detected an accurate value for the eccentricity of the planet and so (as of 2023) only an upper limit for the eccentricity of the planet has been set by astronomers. == Habitability ==