About this world
HD 211970 b is a sub-Neptune orbiting HD 211970, an orange dwarf (type K7V) 42.8 light-years from Earth. It is about 3.7 times the size of Earth (its size estimated from its mass), with at least 13 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 25.2 days at 0.14 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 399 K (126 °C): too cold for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2019 by radial velocity with Las Campanas Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.