About this world
HD 177830 c is a Neptune-like planet orbiting HD 177830, an orange dwarf (type K0) 205 light-years from Earth. It is about 0.7 times the size of Jupiter (its size estimated from its mass), with at least 0.15 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 111 days at 0.51 AU from its star, on a strongly elongated orbit (e = 0.3).
Its equilibrium temperature is about 539 K (266 °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 W. M. Keck Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 177830 has 2 known planets; the others are HD 177830 b.