Kepler-124: A Distant Star With Three Transiting Planets

Kepler-124 is a star located 1370 light-years away. It has 0.73 solar masses, 0.67 solar radii, and a temperature of 5130 K, and it is 1.82 billion years old. Its reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's. Three planets are known to orbit this host: Kepler-124 b, Kepler-124 c, and Kepler-124 d. All three were discovered by the transit method, in which a planet passing in front of its star from our viewpoint causes a small dip in observed brightness, and repeated dips help establish orbital periods. All three were discovered in 2014.

Kepler-124 b is a Sub-Earth, a size class for planets smaller than Earth. It has an orbital period of 3.41 days and a radius of 0.73 Earth radii, smaller than Earth's radius. Among the listed planets, it has the shortest year and the smallest radius by reported estimates. Kepler-124 c is a Super-Earth, a class reaching up to 2.5 times Earth's radius. Its orbital period is 13.8 days - the second-shortest among the listed planets - and its radius is 1.75 Earth radii, larger than Earth's and the largest among the listed planets. Kepler-124 d is classified as Earth-like, a class that stays within 1.5 times Earth's radius. It has an orbital period of 31 days and a radius of 1.11 Earth radii, larger than Earth's. Among the listed planets, Kepler-124 d has the longest year and the second-smallest radius by reported estimates.

The star's age is 1.82 billion years.