About this world
HD 10180 e is a Neptune-like planet orbiting HD 10180, a yellow, Sun-like star (type G1V) 127 light-years from Earth. It is about 5.4 times the size of Earth (its size estimated from its mass), with at least 25 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 49.7 days at 0.27 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 578 K (305 °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 2010 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 10180 has 6 known planets; the others are HD 10180 c, HD 10180 d, HD 10180 f, HD 10180 g and HD 10180 h.