About this world
HD 154857 b is a gas giant orbiting HD 154857, a yellow, Sun-like star (type G5V) 207 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 2.5 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 409 days at 1.3 AU from its star, on a strongly elongated orbit (e = 0.46).
Its equilibrium temperature is about 360 K (87 °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 2004 by radial velocity with Anglo-Australian Telescope. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 154857 has 2 known planets; the others are HD 154857 c.