Description: GJ 1214 b is an exoplanet that orbits the star GJ 1214, and was discovered in December 2009. Its parent star is 48 light-years (15 pc) from the Sun, in the constellation Ophiuchus. At the time of its discovery, GJ 1214 b was the most likely known candidate for being an ocean planet. For that reason, scientists at that time often called the planet a "waterworld". However, a recent study of the planet's internal structure informed by observations taken with the James Webb Space Telescope suggests that a "waterworld" composition is implausible and the planet is more likely to host a thick gaseous envelope consisting of hydrogen, helium, water and other volatile chemicals such as methane or carbon dioxide.
Mass (Jupiter mass): 0.0264608191551613 MJ
Radius (Jupiter radius): 0.244 RJ
Density: 2.26 g/cm³
Equilibrium Temperature: 567.0 K
Orbital Period: 1.58040453 days
Semi-major Axis: 0.01505 AU
Eccentricity: 0.0062
Inclination: 88.98°
Host Star: GJ 1214
Spectral Type: M4 V
Temperature: 3101.0 K
Stellar Mass: 0.18 M☉
Stellar Radius: 0.22 R☉
Planet Letter: b
Object ID: 3.10969
Host ID: 2.10127
Discovery Date: 2009-12
Discovery Year: 2009
Discovery Method: Transit
Discovery Locale: Ground
Discovery Facility: MEarth Project
Discovery Instrument: Apogee CCD Sensor