TOI-406 and Its Two Known Worlds

TOI-406 is a star 101 light-years away. Its spectral type is M3, making it a small, cool red dwarf. The star has a reported mass of 0.408 solar masses and a radius of 0.41 solar radii, both smaller than the Sun's, and a temperature of 3390 K, cooler than the Sun's. Two planets are known to orbit this host.

TOI-406 c was discovered by the transit method in 2024, the same year as TOI-406.01. It is classified as Earth-like, with a radius of 1.32 Earth radii and a mass of 2.08 Earth masses, both larger than Earth's. Its mean density is 4.98 g/cm³, 0.904 times Earth's. It completes an orbit in 3.31 days, the shortest year among the listed planets. Among the listed planets, it also has the smallest radius and the smallest reported mass.

TOI-406.01 orbits in 13.2 days, the longest year among the listed planets. It is classified as a Super-Earth, with a radius of 2.08 Earth radii and a mass of 6.57 Earth masses. Its radius and mass are both larger than Earth's, and its mean density is 4.02 g/cm³, 0.73 times Earth's. Among the listed planets, it has the largest radius and the largest reported mass.