About this world
K2-22 b is a sub-Neptune orbiting K2-22, a cool red dwarf (type M0V) 795 light-years from Earth. It is about 2.3 times the size of Earth and holds 440 Earth masses. It completes an orbit every 9.15 hours at 0.009 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 2,100 K (1,827 °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: 3 spectroscopic observations, all of them with the James Webb Space Telescope.
It was discovered in 2015 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction.