About this world
HD 285968 b is a sub-Neptune orbiting HD 285968, a cool red dwarf (type M2V) 30.9 light-years from Earth. It is about 2.8 times the size of Earth (its size estimated from its mass), with at least 8.4 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 8.78 days at 0.066 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 450 K (177 °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 2008 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.