Kepler-218 and Its Three Planets

Kepler-218 is a star located 2140 light-years away. It has a mass of 1.01 solar masses, a radius of 1.02 solar radii, and a temperature of 5540 K, which is cooler than the Sun's. Its age is 5.62 billion years. Three planets orbit this host.

Kepler-218 b, Kepler-218 c, and Kepler-218 d were 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. Kepler-218 b was found in 2014, along with Kepler-218 c, while Kepler-218 d was found in 2016.

Kepler-218 b is an Earth-like planet with a radius of 1.48 Earth radii, larger than Earth's. Its orbital period, the time it takes to complete one orbit, is 3.62 days, the shortest year among the listed planets. Kepler-218 c is a Neptune-like planet with a radius of 3.14 Earth radii, larger than Earth's and the largest radius among the listed planets. Its orbital period is 44.7 days, the second-shortest year among the listed planets. Kepler-218 d is also Neptune-like, with a radius of 2.66 Earth radii, larger than Earth's. Its orbital period is 125 days, the longest year among the listed planets.