Kepler-203 and Its Three Planets

Kepler-203 is a star located 2290 light-years away. It is 5.5 billion years old, has 1 solar masses, 1.03 solar radii, and a temperature of 5790 K. Three planets are known to orbit this host.

All three planets were discovered by transit in 2014. Kepler-203 b is Neptune-like, with a radius of 2.57 Earth radii and an orbital period of 3.16 days. Among the listed planets, it has the shortest year and the largest radius. Kepler-203 c is a Super-Earth with a radius of 2.47 Earth radii and an orbital period of 5.37 days, the second-shortest year and second-smallest radius among the listed planets. Kepler-203 d is Earth-like, with a radius of 1.44 Earth radii and an orbital period of 11.3 days, the longest year and smallest radius among the listed planets. Each planet's reported radius estimate is larger than Earth's. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness; repeated dips help establish orbital periods.