About this world
Kepler-396 b is a sub-Neptune orbiting Kepler-396, a yellow, Sun-like star 730 light-years from Earth. It is about 3.5 times the size of Earth and holds 76 Earth masses. It completes an orbit every 43 days at 0.24 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 496 K (223 °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 2013 by transit with Kepler. A planet crosses its star and dims it by a tiny, periodic fraction. Kepler-396 has 2 known planets; the others are Kepler-396 c.