About this world
TOI-7166 b is a sub-Neptune orbiting TOI-7166, a cool red dwarf (type M4.5+/-) 116 light-years from Earth. It is about 2 times the size of Earth. It completes an orbit every 12.9 days at 0.062 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 249 K (−24 °C), which places it in the optimistic habitable zone: the band where liquid water could exist on a rocky surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2025 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.