About this world
HIP 41378 c is a sub-Neptune orbiting HIP 41378, a yellow-white F-type star (type F6) 347 light-years from Earth. It is about 2.7 times the size of Earth and holds 6 Earth masses. It completes an orbit every 31.7 days at 0.21 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 757 K (484 °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 2016 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. HIP 41378 has 6 known planets; the others are HIP 41378 b, HIP 41378 g, HIP 41378 e, HIP 41378 d and HIP 41378 f.