About this world
Kepler-663 b is a sub-Neptune orbiting Kepler-663, a yellow, Sun-like star 3.47 thousand light-years from Earth. It is about 2.6 times the size of Earth. It completes an orbit every 5 days at 0.056 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 917 K (644 °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 Kepler. A planet crosses its star and dims it by a tiny, periodic fraction.