TOI-7166 b, discovered in 2025, is a super-Earth to mini-Neptune transition world orbiting an M4 red dwarf every 12.9 days at 0.062 AU. Its 4.7 Earth masses and 2.01 Earth radii yield a low density of about 0.58 g/cm³, implying a thick hydrogen-helium envelope possibly hiding a water layer beneath. Receiving 1.07 times Earth’s solar flux, it maintains an equilibrium temperature of 249 K (-24°C), making it a prime target for habitability probes—liquid water might exist in subsurface oceans or atmospheric hazes. At just 115 light-years away, it’s ideal for JWST spectroscopy to detect biosignatures like water vapor or methane, advancing our quest for life beyond Earth.
