Kepler-167 and Its Four Worlds

Kepler-167 is a K4 star located 1120 light-years away, with four planets known to orbit it. The star is cooler than the Sun, with a temperature of 4890 K, and smaller in both mass and radius: 0.77 solar masses and 0.726 solar radii. Its age is 3.3 billion years. A K-type designation places it in a temperature class cooler than the Sun's G-type.

All four planets were found by the transit method, in which a planet crosses in front of its star and causes a slight dip in observed brightness. Kepler-167 b and Kepler-167 c were both discovered in 2014, and both are Super-Earths. Kepler-167 b has an orbital period of 4.39 days and a radius of 1.72 Earth radii; Kepler-167 c orbits in 7.41 days with a radius of 1.67 Earth radii. Among the listed planets, Kepler-167 b has the shortest year and the second-largest radius, while Kepler-167 c has the second-shortest year and the second-smallest radius.

Kepler-167 d, discovered in 2016, is an Earth-like planet with an orbital period of 21.8 days and a radius of 1.24 Earth radii - the smallest radius among the listed planets, and the second-longest year. Also found in 2016, Kepler-167 e is a Jupiter-like planet with a radius of 10.2 Earth radii and a mass of 321 Earth masses, both larger than Earth's. Its orbital period is 1070 days, the longest among the listed planets, and it has the largest radius of the four. Its mean density is 1.69 g/cm³, which is 0.306 times Earth's.