Kepler-223: A Four-Planet System

Kepler-223 is a star located 6070 light-years away. It hosts four planets, all discovered by the transit method in 2014. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness. The host star is 4.27 billion years old and has a mass of 0.98 solar masses, a radius of 0.98 solar radii, and a temperature of 5750 K.

Kepler-223 b is a Neptune-like planet with a mass of 7.4 Earth masses, a radius of 2.99 Earth radii, and an orbital period of 7.38 days. Kepler-223 c is also Neptune-like, with a mass of 5.1 Earth masses, a radius of 3.44 Earth radii, and an orbital period of 9.85 days. Kepler-223 d is Jupiter-like, with a mass of 8 Earth masses, a radius of 5.24 Earth radii, and an orbital period of 14.8 days. Kepler-223 e is also Jupiter-like, with a mass of 4.8 Earth masses, a radius of 4.6 Earth radii, and an orbital period of 19.7 days. Each planet's radius estimate and mass estimate are larger than Earth's.

Among the listed planets, Kepler-223 b has the shortest year, at 7.38 days, and the smallest radius, at 2.99 Earth radii. Kepler-223 e has the longest year, at 19.7 days. Kepler-223 d has the largest radius, at 5.24 Earth radii, and the largest reported mass, at 8 Earth masses. Kepler-223 e has the smallest reported mass, at 4.8 Earth masses. Kepler-223 c has the second-shortest year, at 9.85 days, the second-smallest radius, at 3.44 Earth radii, and the second-smallest reported mass, at 5.1 Earth masses. Kepler-223 b has the second-largest reported mass, at 7.4 Earth masses, while Kepler-223 d has the second-longest year, at 14.8 days, and Kepler-223 e has the second-largest radius, at 4.6 Earth radii. The mean density of Kepler-223 b is 1.53 g/cm³, 0.277 times Earth's, the highest among these planets.