About this world
HD 211810 b is a gas giant orbiting HD 211810, a yellow, Sun-like star (type G5) 211 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 0.67 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 4.27 years at 2.7 AU from its star, on a strongly elongated orbit (e = 0.68).
Its equilibrium temperature is about 178 K (−95 °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 2018 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.