About this world
Kepler-289 e is a sub-Neptune orbiting Kepler-289, a yellow, Sun-like star 2.3 thousand light-years from Earth. It is about 2.9 times the size of Earth and holds 17 Earth masses. It completes an orbit every 330 days at 0.93 AU from its star.
Its equilibrium temperature is about 286 K (13 °C), which places it in the optimistic habitable zone: the band where liquid water could exist on a rocky surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2025 by transit with Kepler. A planet crosses its star and dims it by a tiny, periodic fraction. Kepler-289 has 4 known planets; the others are Kepler-289 b, Kepler-289 d and Kepler-289 c.