About this world
HD 219139 b is a gas giant orbiting HD 219139, a giant star (type G5III) 342 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 0.78 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 276 days at 0.94 AU from its star.
Its equilibrium temperature is about 805 K (532 °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 2021 by radial velocity with Okayama Astrophysical Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.