kepler-186f is in the habitable zone of kepler-186, so liquid water may be on its surface. however, just because a planet is in the habitable zone, dos not mean it is habitable. the find is still thought to be important, however, since it has a size similar to earth's. it only receives one third of the sunlight earth gets, hence its temperature is thought to be -91 celsius. however, a greenhouse effect can help heat the surface up, and make it warmer.