About this world
HD 4203 b is a gas giant orbiting HD 4203, a yellow, Sun-like star (type G5) 265 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 2.2 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 432 days at 1.2 AU from its star, on a strongly elongated orbit (e = 0.52).
Its equilibrium temperature is about 297 K (24 °C), which places it in the optimistic 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 2001 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 4203 has 2 known planets; the others are HD 4203 c.