Kepler-174d

Kepler-174d is an exoplanet on the outer edge of the habitable zone. Its mass and composition are not known, but it is probably a water world because of its radius of 2.19 earths. Its orbital period is about 247 days with a semi-major axis of 0.651 AU. It orbits a smaller, cooler star than the Sun, a red dwarf. Because it is relatively far from a small star, it is probably freely rotating, evenly dispersing heat on the surface, thus making more of its surface habitable. It is 1175 light years away.