About this world
KMT-2021-BLG-0171L b is a sub-Neptune orbiting KMT-2021-BLG-0171L, a yellow, Sun-like star 15 thousand light-years from Earth. It is about 3.4 times the size of Earth (its size estimated from its mass) and holds 11 Earth masses.
At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2022 by microlensing with KMTNet. A foreground star's gravity magnifies a background star; a planet adds a blip.