About this world
HIP 56640 b is a gas giant orbiting HIP 56640, a giant star (type K1III) 399 light-years from Earth. It is about 1.1 times the size of Jupiter (its size estimated from its mass) and holds 6.8 Jupiter masses. It completes an orbit every 7.33 years at 4.5 AU from its star.
Its equilibrium temperature is about 239 K (−34 °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 2021 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum.