About this world
HIP 5158 b is a gas giant orbiting HIP 5158, an orange dwarf 168 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 1.4 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 346 days at 0.89 AU from its star, on a strongly elongated orbit (e = 0.52).
Its equilibrium temperature is about 220 K (−53 °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 2009 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HIP 5158 has 2 known planets; the others are HIP 5158 c.