<Tr> <Td_colspan="2"> Open Exoplanet Catalogue </Td> <Td> data </Td> </Tr> <P> Kepler - 22b, also known by its Kepler object of interest designation KOI - 087.01, is an extrasolar planet orbiting within the empirical habitable zone of the Sun - like star Kepler - 22 . It is located about 638 light - years (196 pc) from Earth in the constellation of Cygnus . It was discovered by NASA's Kepler Space Telescope in December 2011 and was the first known transiting planet to orbit within the habitable zone of a Sun - like star . Kepler - 22 is too dim to be seen with the naked eye . </P> <P> Kepler - 22b's size is roughly twice that of Earth . Its mass and surface composition are unknown . An Earth - like composition for the planet has been ruled out . It is likely to have a volatile - rich composition with a liquid or gaseous outer shell . The only parameters of the planet's orbit that are currently available are its orbital period, which is about 290 days, and its inclination, which is approximately 90 ° . Evidence suggests that the planet has a moderate surface temperature, assuming that the surface is not subject to extreme greenhouse heating . In the absence of an atmosphere, its equilibrium temperature (assuming an Earth - like albedo) would be approximately 262 K (− 11 ° C), compared to Earth's 255 K (− 18 ° C) </P> <P> The planet's first transit was observed on 12 May 2009 . Confirmation of the existence of Kepler - 22b was announced on 5 December 2011 . </P>

What is the surface of kepler 22b like