Kepler-186e

Kepler-186e is a planet in or near the habitable zone. Unlike Kepler-186f, it is on the inner edge, possibly making it have a runaway greenhouse effect, like Venus.

Mass, density and composition

It is only slightly larger than Earth, with a radius 1.27–1.33 times that of Earth. Its mass is not known but it is likely to have a similar composition to Earth, giving it a mass of about 2.29–2.72 times the mass of the Earth. It has a semi-major axis of 0.110–0.1216 AU and an orbital period of 22.4077 days.

Formation, tidal evolution and habitability

Due to its proximity to its star, Kepler-186, it is probably tidally locked, facing one side to its star at all times, and one side facing away from its star at all times. The side in permanent daylight would be extremely hot and the side in permanent darkness would be extremely cold. But between these hostile environments, there would be a sliver of habitability, which could support life. It was discovered in 2014 and lies 492 light years away in the constellation of Cygnus. It has a temperature of 323 K.

See also

• Habitability of red dwarf systems
• List of potentially habitable exoplanets

External links

• NASA – Kepler Mission.
• NASA – Kepler Discoveries – Summary Table.
• Habitable Exolanets Catalog at UPR-Arecibo.