K2-21b, also known as EPIC 206011691 b is an exoplanet orbiting K2-21, a red dwarf 273.5 light-years away from Earth,[3] with a period of 9.3 days.[2][4] It has a density of 2.7g/cm3, indicating that it is not a rocky planet.[2] The margin of error is however quite large, with a possible density between 1.1 and 6.4 g/cm3. Due to this error margin, the true nature of its composition is uncertain.
Discovery[1] | |
---|---|
Discovery site | Kepler Space Observatory |
Discovery date | 2015 |
Detection method | Transit |
Orbital characteristics | |
Semi-major axis | 0.0731 AU (10,940,000 km) |
Eccentricity | null[2] |
Orbital period (sidereal) | 9.32414[2] d |
Inclination | 88.3+1.3 −1.1[2] |
Star | K2-21 |
Physical characteristics | |
Mean radius | 1.59+0.42 −0.44[2] REarth |
Mass | null[2] MEarth |
Mean density | 2.7+3.7 −1.6 g cm−3 |
Temperature | 500 K (227 °C; 440 °F) |
2015 in space | ||||||
---|---|---|---|---|---|---|
| ||||||
Space probe launches ![]() |
| |||||
Impact events |
| |||||
Selected NEOs |
| |||||
Exoplanets ![]() |
| |||||
Discoveries |
| |||||
Comets ![]() | ||||||
Space exploration | ||||||
|
Constellation of Aquarius | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||
Stars |
| ||||||||||
| |||||||||||
| |||||||||||
| |||||||||||
Galaxies |
| ||||||||||
| |||||||||||
| |||||||||||
![]() |