K2-146 and Its Two Super-Earths

K2-146 is an M3.0 V star located 259 light-years away, with two planets orbiting it. The host is a small, cool red dwarf with a reported mass of 0.358 solar masses and a radius of 0.35 solar radii. Its reported temperature of 3390 K is cooler than the Sun's. Both planets were found by the transit method, which detects the small dip in a star's brightness when a planet crosses in front of it; repeated dips help establish orbital periods.

K2-146 b, discovered in 2018, is a Super-Earth with a mass of 5.77 Earth masses, a radius of 2.05 Earth radii, and an orbital period of 2.64 days. Its mean density is 3.69 g/cm³, 0.67 times Earth's. K2-146 c, discovered in 2019, is also a Super-Earth, with a mass of 7.49 Earth masses, a radius of 2.19 Earth radii, and an orbital period of 4 days. Its mean density is 3.93 g/cm³, 0.713 times Earth's. Both planets have reported radius and mass estimates larger than Earth's. Among the listed planets, K2-146 b has the shortest year by reported estimates at 2.64 days, the smallest radius by reported estimates at 2.05 Earth radii, and the smallest reported mass at 5.77 Earth masses. K2-146 c has the longest year by reported estimates at 4 days, the largest radius by reported estimates at 2.19 Earth radii, and the largest reported mass at 7.49 Earth masses. The star's reported mass and radius estimates are both smaller than the Sun's.