Kepler-137 and Its Two Known Planets

Kepler-137 is a star located 988 light-years away, and it hosts two known planets. The star is 4.27 billion years old, with a reported mass estimate of 0.87 solar masses and a radius estimate of 0.81 solar radii, making both smaller than the Sun's. Its temperature is 5270 K, cooler than the Sun's.

The two planets were both discovered in 2014 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. Kepler-137 b is classified as Earth-like, with a radius of 1.47 Earth radii, larger than Earth's, and an orbital period of 8.44 days. Kepler-137 c is classified as a Super-Earth, with a radius of 1.88 Earth radii, also larger than Earth's, and an orbital period of 18.7 days. Among the listed planets, Kepler-137 b has the shortest year and the smallest radius, while Kepler-137 c has the longest year and the largest radius. An Earth-like planet stays within 1.5 times Earth's radius, while a Super-Earth reaches 2.5 times.