Kepler-153 and Its Two Neptune-Like Planets

Kepler-153 is a star located 1500 light-years away, and two planets have been found in orbit around it. The host star is 4.79 billion years old, with a mass of 0.83 solar masses, a radius of 0.8 solar radii, and a temperature of 5260 K. Its reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's.

Both planets were discovered by transit in 2014. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness. Kepler-153 b and Kepler-153 c are both Neptune-like, a size class that reaches 4 times Earth's radius. Kepler-153 b has a radius of 2.92 Earth radii and an orbital period of 18.9 days, making it the shortest year among the listed planets. Its reported radius estimate is larger than Earth's. Kepler-153 c has a radius of 2.53 Earth radii and an orbital period of 46.9 days, the longest year among the listed planets, and its reported radius estimate is also larger than Earth's. Among the listed planets, Kepler-153 b has the largest radius by reported estimates, while Kepler-153 c has the smallest.