Kepler-351 and Its Three Planets

Kepler-351 is a star located 3540 light-years away. It is 4.9 billion years old and has a mass of 0.81 solar masses and a radius of 0.78 solar radii, both smaller than the Sun's corresponding values. Its temperature of 5230 K is cooler than the Sun's. Three planets are known to orbit this host.

All three planets are Neptune-like, a size class that reaches up to four times Earth's radius. They were detected 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-351 b and Kepler-351 c were discovered in 2014, while Kepler-351 d was discovered in 2016. Each planet's radius is larger than Earth's.

Kepler-351 b has an orbital period of 37.1 days and a radius of 3.06 Earth radii. Among the listed planets, it has the shortest year by reported estimates and the second-smallest radius. Kepler-351 c has an orbital period of 57.2 days and a radius of 3.19 Earth radii, giving it the second-shortest year and the largest radius among the listed planets. Kepler-351 d has an orbital period of 143 days and a radius of 2.72 Earth radii. It has the longest year and the smallest radius among the listed planets.

Kepler-351 d's discovery in 2016 makes it the most recently reported planet in this system.