Kepler-186f
Kepler-186f (also known by its Kepler object of interest designation KOI-571.05) is an Earth-sized exoplanet orbiting within the habitable zone of the red dwarf star Kepler-186, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about 580 light-years (180 parsecs) from Earth in the constellation of Cygnus.
Artist’s depiction of Kepler-186f (foreground) as a rocky Earth-like planet in the habitable zone, with the Kepler-186 system visible in the background (bottom left). The actual appearance and composition of the exoplanet is not currently known. | |
| Discovery | |
|---|---|
| Discovered by | Elisa Quintana |
| Discovery site | Kepler Space Observatory |
| Discovery date | 17 April 2014 |
| Transit | |
| Orbital characteristics | |
| 0.432 ± 0.01 AU | |
| Eccentricity | 0.04 |
| 129.9444 ± 0.0012 d 0.355772 y | |
| Inclination | 89.9 |
| Star | Kepler-186 |
| Physical characteristics | |
Mean radius | 1.17 ± 0.08 R🜨 |
| Mass | 1.44+2.33 −1.12 ME |
| 1.17 (est.) g | |
| Temperature | Teq: 188 K (−85 °C; −121 °F) |
Kepler-186f orbits its star at a distance of about 0.43 AU (64,000,000 km; 40,000,000 mi) from its host star with an orbital period of roughly 130 days, and a mass and radius around 1.44 and 1.17 times that of Earth, respectively. As one of the more promising candidates for habitability, it was the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star. However, key components still need to be found to determine its habitability for life, including an atmosphere and its composition and if liquid water can exist on its surface.
Analysis of three years of data was required to find its signal. NASA’s Kepler telescope detected it using the transit method (in which the dimming effect that a planet causes as it crosses in front of its star is measured), along with four additional planets orbiting much closer to the star (all modestly larger than Earth). The results were presented initially at a conference on 19 March 2014 and some details were reported in the media at the time. The public announcement was on 17 April 2014, followed by publication in Science.