Kepler-139 and Its Five Planets

Kepler-139 is a single-star system 1280 light-years away. The star is 5.62 billion years old, with a mass of 1.05 solar masses. Its radius is 1.12 solar radii, and its temperature is 5680 K. Five planets are known to orbit this host.

Kepler-139 b and Kepler-139 c are both Neptune-like planets discovered by transit in 2014. Kepler-139 b has an orbital period of 15.8 days and a radius of 2.94 Earth radii. Kepler-139 c has an orbital period of 157 days and a radius of 3.38 Earth radii.

Kepler-139 d is a Super-Earth discovered by transit in 2023. It has a minimum mass of 4.66 Earth masses, an orbital period of 7.31 days, and a radius of 1.7 Earth radii. Among the listed planets, Kepler-139 d has the shortest year and Kepler-139 b has the second-shortest year. Kepler-139 e was discovered by radial velocity in 2023. It has a minimum mass of 426 Earth masses and an orbital period of 2050 days. Among the listed planets, Kepler-139 e has the longest year and Kepler-139 f has the second-longest year. Kepler-139 f was discovered by transit timing variations in 2025. It has a mass of 36 Earth masses and an orbital period of 355 days.

Several planets are larger than Earth: the radii of Kepler-139 b, Kepler-139 c, and Kepler-139 d are larger than Earth's, and the minimum masses of Kepler-139 d and Kepler-139 e are larger than Earth's. Kepler-139 e's minimum mass is roughly 1.34 times Jupiter's mass. Kepler-139 f's reported mass estimate is larger than Earth's. The star's reported mass and radius estimates are larger than the Sun's, while its reported temperature is cooler than the Sun's.