Kepler-381 and Its Three Planets

Kepler-381 is a star located 872 light-years from Earth. It is host to three planets, all 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. The star is estimated to be 2.57 billion years old, with a mass of 1.44 solar masses and a radius of 2.02 solar radii. Its reported temperature is 6340 K, hotter than the Sun's, and its mass and radius estimates are both larger than the Sun's.

Kepler-381 b was discovered in 2014 and is classified as a Sub-Earth, meaning its radius is smaller than Earth's. Its radius is 0.99 Earth radii, and it completes one orbit, or year, in 5.63 days. Among the listed planets, it has the shortest year and the smallest radius.

Kepler-381 c, also discovered in 2014, is classified as Earth-like, a size class that stays within 1.5 times Earth's radius. It has a radius of 1.12 Earth radii and an orbital period of 13.4 days. Among the listed planets, it has the longest year and the largest radius.

Kepler-381 d was discovered in 2021 and is also Earth-like. Its radius is 1.07 Earth radii, larger than Earth's. It orbits its star every 8.26 days. Among the listed planets, it has the second-shortest year and the second-smallest radius.