TOI-1246 and Its Four Worlds

TOI-1246 is a K V star 553 light-years away, a main-sequence dwarf with a spectral class cooler than the Sun's. Its mass is 0.889 solar masses and its radius is 0.865 solar radii, both smaller than the Sun's, and its temperature of 5210 K is cooler than the Sun's. The star is 6.3 billion years old. Four planets orbit TOI-1246: TOI-1246 b, TOI-1246 c, TOI-1246 d, and TOI-1246 e. All four were discovered by transit in 2022.

TOI-1246 b is a Neptune-like planet with a mass of 8.1 Earth masses and a radius of 3.01 Earth radii. Its orbital period is 4.31 days, the shortest among these four planets. TOI-1246 c is a Super-Earth with a mass of 9.1 Earth masses and a radius of 2.45 Earth radii, the smallest radius among the four. Its orbital period is 5.9 days, the second-shortest here.

TOI-1246 d is a Neptune-like planet with the smallest reported mass of the group at 5.4 Earth masses, a radius of 3.43 Earth radii, and an orbital period of 18.7 days, the second-longest among the four. TOI-1246 e is a Neptune-like planet with the largest reported mass at 14.5 Earth masses and the largest radius at 3.51 Earth radii. Its orbital period of 37.9 days is the longest among these planets. Each planet's radius exceeds Earth's, as does each planet's mass estimate. Estimated mean densities are 1.64 g/cm³ for TOI-1246 b, 3.4 g/cm³ for TOI-1246 c, 0.736 g/cm³ for TOI-1246 d, and 1.84 g/cm³ for TOI-1246 e.