About this world
HD 117618 b is a Neptune-like planet orbiting HD 117618, a yellow, Sun-like star (type G2V) 123 light-years from Earth. It is about 0.77 times the size of Jupiter (its size estimated from its mass), with at least 0.17 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 25.8 days at 0.18 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 746 K (473 °C): far too hot 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.