About this world
AU Mic e is a Neptune-like planet orbiting AU Mic, a cool red dwarf (type M1V) 31.7 light-years from Earth. It is about 4.9 times the size of Earth (its size estimated from its mass) and holds 21 Earth masses. It completes an orbit every 33.1 days at 0.17 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 381 K (108 °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 2025 by radial velocity with Mauna Kea Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. AU Mic has 4 known planets; the others are AU Mic b, AU Mic d and AU Mic c.