About this world
HD 187123 c is a gas giant orbiting HD 187123, a yellow, Sun-like star (type G3V) 150 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass) and holds 2.9 Jupiter masses. It completes an orbit every 10.4 years at 4.9 AU from its star, on a strongly elongated orbit (e = 0.25).
Its equilibrium temperature is about 135 K (−138 °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 2008 by radial velocity with W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 187123 has 2 known planets; the others are HD 187123 b.