About this world
HD 220842 b is a gas giant orbiting HD 220842, a yellow-white F-type star (type F8) 211 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 3.2 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 218 days at 0.74 AU from its star, on a strongly elongated orbit (e = 0.4).
Its equilibrium temperature is about 398 K (124 °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 2016 by radial velocity with Haute-Provence Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.