About this world
TOI-4409 b is a Neptune-like planet orbiting TOI-4409, an orange dwarf (type K) 585 light-years from Earth. It is about 0.66 times the size of Jupiter and holds 0.047 Jupiter masses. It completes an orbit every 92.5 days at 0.37 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 305 K (32 °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 2026 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.