Kepler-186f

Kepler-186f is an exoplanet orbiting the red dwarf Kepler-186, about 500 light-years from the Earth. It is the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star.

Kepler-186f orbits a star with about 4% of the Sun's luminosity with an orbital period of 129.9 days and an orbital radius of about 0.36 or 0.40 times that of Earth's (compared to 0.39 AU for Mercury). The habitable zone for this system is estimated conservatively to extend over distances receiving from 88% to 25% of Earth's illumination (from 0.22 to 0.40 AU). Kepler-186f receives about 32%, placing it within the conservative zone but near the outer edge, similar to the position of Mars in our Solar System.