About this world
GJ 1214 b is a sub-Neptune orbiting GJ 1214, a cool red dwarf (type M4V) 47.8 light-years from Earth. It is about 2.7 times the size of Earth and holds 8.4 Earth masses. It completes an orbit every 1.58 days at 0.015 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 567 K (294 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium. Its atmosphere has already been studied: 27 spectroscopic observations, 3 of them with the James Webb Space Telescope.
It was discovered in 2009 by transit with MEarth Project. A planet crosses its star and dims it by a tiny, periodic fraction.