About this world
HD 231701 b is a gas giant orbiting HD 231701, a yellow-white F-type star (type F8V) 355 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 1.1 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 142 days at 0.57 AU from its star.
Its equilibrium temperature is about 483 K (210 °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 2007 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.