About this world
HD 210277 b is a gas giant orbiting HD 210277, a yellow, Sun-like star (type G0V) 69.5 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 1.3 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 442 days at 1.1 AU from its star, on a strongly elongated orbit (e = 0.48).
Its equilibrium temperature is about 260 K (−13 °C), which places it in the conservative habitable zone: the band where liquid water could exist on a rocky surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 1998 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.