Kepler-231: A Cool Red Dwarf and Its Two Super-Earths

Kepler-231 is an M1 V star, a small, cool red dwarf, located 1030 light-years away. It is a single-star system with two known planets. The star's reported mass estimate is 0.59 solar masses, its reported radius estimate is 0.57 solar radii, its temperature is 4150 K, and its age is 3.47 billion years. Its reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's.

Both planets were discovered by transit in 2014. Kepler-231 b is a Super-Earth with an orbital period of 10.1 days and a radius of 1.73 Earth radii. Kepler-231 c is also a Super-Earth, with an orbital period of 19.3 days and a radius of 1.93 Earth radii. Both planets' reported radius estimates are larger than Earth's. Among the listed planets, Kepler-231 b has the shortest year and the smallest radius by reported estimates, while Kepler-231 c has the longest year and the largest radius.