About this world
HD 3167 d is a sub-Neptune orbiting HD 3167, an orange dwarf (type K0V) 154 light-years from Earth. It is about 2.6 times the size of Earth (its size estimated from its mass) and holds 7.3 Earth masses. It completes an orbit every 8.4 days at 0.077 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.35).
Its equilibrium temperature is about 865 K (592 °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 2017 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 3167 has 4 known planets; the others are HD 3167 b, HD 3167 c and HD 3167 e.