About this world
Kepler-139 b is a sub-Neptune orbiting Kepler-139, a yellow, Sun-like star 1.28 thousand light-years from Earth. It is about 2.9 times the size of Earth and holds 7 Earth masses. It completes an orbit every 15.8 days at 0.13 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 752 K (479 °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-139 has 5 known planets; the others are Kepler-139 d, Kepler-139 c, Kepler-139 f and Kepler-139 e.