About this world
TOI-2406 b is a sub-Neptune orbiting TOI-2406, a cool red dwarf (type M4V) 181 light-years from Earth. It is about 2.9 times the size of Earth and holds 16 Earth masses. It completes an orbit every 3.08 days at 0.023 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 449 K (176 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2021 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.