About this world
HD 191939 f is a gas giant orbiting HD 191939, a yellow, Sun-like star (type G9V) 175 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 2.9 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 7.93 years at 3.7 AU from its star.
Its equilibrium temperature is about 125 K (−148 °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 2022 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 191939 has 6 known planets; the others are HD 191939 b, HD 191939 c, HD 191939 d, HD 191939 e and HD 191939 g.