Comparison of "habitable zone" of Kepler 22 system and our solar system (NASA/Kepler)

Today sees the announcement that one of the “candidate” planets listed from NASA’s Kepler mission back in February is now confirmed, and it’s a key one. At 2.4 times the diameter of the Earth the planet Kepler 22-b also orbits its parent star (which is a slightly less massive G-dwarf star than the Sun and 25% less luminous) in 290 Earth-days, which places it within the nominal “ habitable zone “. This system is about 600 light years from us.