Kepler-20f
| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
 | ||
| Parent star | ||
| Star | Kepler-20 (KOI-070) | |
| Constellation | Lyra | |
| Right ascension | (α) | 19h 10m 47.524s |
| Declination | (δ) | +42° 20′ 19.30″ |
| Apparent magnitude | (mV) | 12.51 |
| Mass | (m) | 0.912±0.035 M☉ |
| Radius | (r) | 0.944+0.06 −0.095 R☉ |
| Temperature | (T) | 5466±93 K |
| Metallicity | [Fe/H] | 0.02±0.04 |
| Age | 8.8+4.7 −2.7 Gyr | |
| Physical characteristics | ||
| Mass | (m) | 0.66-3.04 M⊕ |
| Radius | (r) | 1.034+0.100 −0.127 R⊕ |
| Temperature | (T) | 705 |
| Orbital elements | ||
| Semimajor axis | (a) | 0.1104 AU |
| Eccentricity | (e) | <0.32 |
| Orbital period | (P) | 19.57706 d |
| Inclination | (i) | 88.68+0.17 −0.14° |
| Discovery information | ||
| Discovery date | 20 December 2011 | |
| Discoverer(s) | Kepler team | |
| Discovery method | Transit (Kepler Mission) | |
| Discovery status | Conference announcement | |
Kepler-20f is an exoplanet orbiting Kepler-20. The planet is notable as it has the closest radius to Earth known so far. The planet is fourth closest to the star, and at 705 K, too hot to have liquid water on its surface. Instead, it is expected to have an atmosphere of water vapour. Along with the other four planets in the system, Kepler-20f was announced on 20 December 2011.
Orbit
Kepler-20e and Kepler-20f compared to Venus and Earth
With a semimajor axis of 0.1104 AU, Kepler-20f's orbit has a period of 19.57706 days (with an extremely small margin of error). The planet also has an inclination of 88.68°, which of course makes its transits observable from the Solar System. Like the other planets of the system, the planet has a high maximum eccentricity of 0.32.