About this world
HD 171028 b is a gas giant orbiting HD 171028, a yellow, Sun-like star (type G0) 364 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 2.6 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 550 days at 1.3 AU from its star, on a strongly elongated orbit (e = 0.59).
Its equilibrium temperature is about 374 K (101 °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 2007 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.