About this world
HD 69830 d is a Neptune-like planet orbiting HD 69830, an orange dwarf (type K0V) 41 light-years from Earth. It is about 4.5 times the size of Earth (its size estimated from its mass), with at least 18 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 197 days at 0.63 AU from its star.
Its equilibrium temperature is about 308 K (35 °C), which places it in the optimistic habitable zone: the band where liquid water could exist on a rocky surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2006 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 69830 has 3 known planets; the others are HD 69830 b and HD 69830 c.