About this world
GJ 667 C b is a sub-Neptune orbiting GJ 667 C, a cool red dwarf (type M1.5V) 23.6 light-years from Earth. It is about 2.3 times the size of Earth (its size estimated from its mass), with at least 5.7 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 7.2 days at 0.05 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 425 K (151 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2012 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. GJ 667 C has 5 known planets; the others are GJ 667 C c, GJ 667 C f, GJ 667 C e and GJ 667 C g.