TOI-1238: A Nearby Star with Two Small Worlds

TOI-1238 is a star 231 light-years away with a spectral type of K7/M0. Its reported mass estimate is 0.59 solar masses, its reported radius estimate is 0.58 solar radii, and its reported temperature is 4090 K; the star’s mass, radius, and temperature are all smaller or cooler than the Sun’s. It also has a reported lower limit of 0.8 billion years for its age. Two planets are known to orbit this host.

TOI-1238 b is an Earth-like planet discovered by transit in 2022. It has a radius of 1.21 Earth radii, a mass of 3.76 Earth masses, and an orbital period of 0.765 days. Its mean density is 11.7 g/cm³, 2.12 times Earth's. Both its radius and mass estimates are larger than Earth’s, and among the listed planets it has the shortest year, the smallest radius, and the smallest reported mass.

TOI-1238 c is a Super-Earth discovered by transit in 2022. It has a radius of 2.11 Earth radii, a mass of 8.32 Earth masses, and an orbital period of 3.29 days. Its mean density is 4.88 g/cm³, 0.886 times Earth's. Both its radius and mass estimates are larger than Earth’s, and among the listed planets it has the longest year, the largest radius, and the largest reported mass.