About this world
WASP-47 d is a sub-Neptune orbiting WASP-47, a yellow, Sun-like star (type G9) 864 light-years from Earth. It is about 3.6 times the size of Earth and holds 16 Earth masses. It completes an orbit every 9.03 days at 0.085 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 885 K (612 °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 2015 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. WASP-47 has 4 known planets; the others are WASP-47 e, WASP-47 b and WASP-47 c.