Kepler-1130 and Its Three Sub-Earth Planets

Kepler-1130 is a star located 813 light-years away with three planets orbiting it. The host star is estimated to be 1.58 billion years old, with a mass of 0.9 solar masses and a radius of 0.81 solar radii. Its temperature is 5400 K, cooler than the Sun's, and its reported mass and radius estimates are both smaller than the Sun's.

All three planets were detected by transit, the 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-1130 b was discovered in 2016 and has an orbital period of 5.45 days and a radius of 0.8 Earth radii. Kepler-1130 c was discovered in 2021 and has an orbital period of 3.27 days and a radius of 0.792 Earth radii. Kepler-1130 d was also discovered in 2021 and has an orbital period of 4.27 days and a radius of 0.645 Earth radii.

All three are Sub-Earths, a size class for planets smaller than Earth. Each has a reported radius estimate smaller than Earth's. Among the listed planets, Kepler-1130 c has the shortest year, at 3.27 days, while Kepler-1130 b has the longest, at 5.45 days, and Kepler-1130 d has the second-shortest, at 4.27 days. Kepler-1130 d has the smallest radius among the listed planets, at 0.645 Earth radii, Kepler-1130 b has the largest, at 0.8 Earth radii, and Kepler-1130 c has the second-smallest, at 0.792 Earth radii.