Kepler-186 f is the first Earth-size planet in the habitable zone. The mass of the planet is not known, therefore one can only speculate about the planet's composition. If it is rocky, it could have liquid water on its surface. Kepler-186 orbits an M-dwarf, a star that is much cooler than the Sun. This is why the system's habitable zone is much closer to the star than in the Solar system. Link to scientific paper Your name Note: Your commit will be vetted before it is merged into the public version. It is crucial that you include a link to a scientific publication. For more information on the meaning of the different datafields see the readme file in the Open Exoplanet Catalogue repository on github.