About this world
KMT-2021-BLG-2609L b is a sub-Neptune orbiting KMT-2021-BLG-2609L, a star 24.4 thousand light-years from Earth. It is about 3.2 times the size of Earth (its size estimated from its mass) and holds 10 Earth masses.
At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2024 by microlensing with KMTNet. A foreground star's gravity magnifies a background star; a planet adds a blip.