About this world
Kepler-123 b is a sub-Neptune orbiting Kepler-123, a yellow-white F-type star 3.33 thousand light-years from Earth. It is about 2.9 times the size of Earth and holds 55 Earth masses. It completes an orbit every 17.2 days at 0.14 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 817 K (544 °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 2014 by transit with Kepler. A planet crosses its star and dims it by a tiny, periodic fraction. Kepler-123 has 2 known planets; the others are Kepler-123 c.