TOI-2202: A K-Type Dwarf with Two Known Planets

TOI-2202 is a K8 V star located 770 light-years from Earth. Its spectral type identifies it as a main-sequence K-type dwarf, a class cooler and redder than the Sun's G-type. The star's reported mass estimate is 0.823 solar masses, smaller than the Sun's, and its reported radius estimate is 0.794 solar radii, also smaller than the Sun's. Its temperature is 5140 K, cooler than the Sun's. TOI-2202 is 7.48 billion years old.

Two planets are known to orbit this host. TOI-2202 b was discovered in 2021 by the transit method, during which a planet passes in front of its star from our viewpoint and causes a small dip in observed brightness; repeated dips help establish orbital periods. Classified as Jupiter-like, it has a mass of 287 Earth masses, a radius of 11 Earth radii, and an orbital period of 11.9 days. Its reported radius estimate is larger than Earth's, as is its reported mass estimate, and its mean density is 1.21 g/cm³, 0.219 times Earth's. Among the listed planets, TOI-2202 b has the shortest year, at 11.9 days, and the largest reported mass, at 287 Earth masses.

TOI-2202 c was also discovered in 2021, by Transit Timing Variations, a method that detects a planet through the slight gravitational nudges it imparts to a transiting companion's orbital clockwork. It has a mass of 117 Earth masses and an orbital period of 24.7 days. Its reported mass estimate is larger than Earth's. Among the listed planets, TOI-2202 c has the longest year, at 24.7 days, and the smallest reported mass, at 117 Earth masses.