Kepler-220 and Its Four Worlds

Kepler-220 is a star located 558 light-years away. It has an age of 8.32 billion years, a mass of 0.65 solar masses, and a radius of 0.64 solar radii, with a temperature of 4590 K. Its reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's. Four planets have been identified around this host.

All four planets were discovered by the transit method, in 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. Kepler-220 b is a Sub-Earth with a radius of 0.81 Earth radii and an orbital period of 4.16 days. It has the shortest year among the listed planets and the smallest radius. Kepler-220 c is a Super-Earth with a radius of 1.57 Earth radii and an orbital period of 9.03 days, the second-shortest year by reported estimates. Its radius estimate is larger than Earth's. Kepler-220 d is a Sub-Earth with a radius of 0.98 Earth radii, the second-smallest among the listed planets, and an orbital period of 28.1 days, the second-longest year. Kepler-220 e is classified as Earth-like, with a radius of 1.33 Earth radii and an orbital period of 45.9 days. Its radius is the second-largest among the listed planets and is larger than Earth's, and its year is the longest among the listed planets.

The star's reported mass estimate is 0.65 solar masses and its reported radius estimate is 0.64 solar radii, both smaller than the Sun's.