About this world
Kepler-857 b is a Neptune-like planet orbiting Kepler-857, a yellow, Sun-like star 3.21 thousand light-years from Earth. It is about 0.61 times the size of Jupiter. It completes an orbit every 85.4 days at 0.38 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 390 K (117 °C): too cold 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.