GJ 1214 b
GJ 1214 b (sometimes Gliese 1214 b, formally named Enaiposha) is an exoplanet that orbits the star GJ 1214, and was discovered in December 2009. Its parent star is 48 light-years from the Sun, in the constellation Ophiuchus. As of 2017, GJ 1214 b is the most likely known candidate for being an ocean planet. For that reason, scientists often call the planet a "waterworld".
| Discovery | |
|---|---|
| Discovered by | David Charbonneau, et al. |
| Discovery site | Fred Lawrence Whipple Observatory |
| Discovery date | December 16, 2009 |
| Transit (MEarth Project) | |
| Designations | |
| Enaiposha | |
| Orbital characteristics | |
| 0.01490±0.00026 AU | |
| Eccentricity | <0.063 |
| 1.580404571(42) d | |
| Inclination | 88.7°±0.1° |
| Semi-amplitude | 14.36±0.53 m/s |
| Star | GJ 1214 |
| Physical characteristics | |
Mean radius | 2.742+0.050 −0.053 R🜨 |
| Mass | 8.17±0.43 M🜨 |
Mean density | 2.20+0.17 −0.16 g/cm3 |
| 10.65+0.71 −0.67 m/s2 (1.09 g) | |
| 19.31+0.53 −0.54 km/s | |
| Albedo | 0.51±0.06 (Bond) |
| Temperature | 553±9 K (280 °C; 536 °F, dayside) 437±19 K (164 °C; 327 °F, nightside) |
It is a super-Earth, meaning it is larger than Earth but is significantly smaller (in mass and radius) than the gas giants of the Solar System. After CoRoT-7b, it was the second super-Earth to have both its mass and radius measured and is the first of a new class of planets with small size and relatively low density. GJ 1214 b is also significant because its parent star is relatively near the Sun and because it transits that parent star, which allows the planet's atmosphere to be studied using spectroscopic methods.
In December 2013, NASA reported that clouds may have been detected in the atmosphere of GJ 1214 b.