Kepler-299 and Its Four Worlds

Kepler-299 is a star located 3430 light-years away. It is 6.03 billion years old, has a mass of 0.95 solar masses, a radius of 0.96 solar radii, and a temperature of 5650 K. Its reported mass estimate is smaller than the Sun's, and its reported temperature is cooler than the Sun's. Four planets are known to orbit this host.

All four were discovered by the transit method, in which a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness, and were reported in 2014. Kepler-299 b is an Earth-like planet with an orbital period of 2.93 days and a radius of 1.32 Earth radii. Kepler-299 c is Neptune-like, with an orbital period of 6.89 days and a radius of 2.65 Earth radii. Kepler-299 d and Kepler-299 e are both Super-Earths; the former has an orbital period of 15.1 days and a radius of 1.86 Earth radii, while the latter has an orbital period of 38.3 days and a radius of 1.87 Earth radii. Each planet's reported radius estimate is larger than Earth's.

Among the listed planets, Kepler-299 b has the shortest year by reported estimates, at 2.93 days, while Kepler-299 e has the longest, at 38.3 days. Kepler-299 c has the second-shortest year, at 6.89 days, and Kepler-299 d the second-longest, at 15.1 days. Kepler-299 b also has the smallest radius among the listed planets, at 1.32 Earth radii, while Kepler-299 c has the largest, at 2.65 Earth radii; Kepler-299 d has the second-smallest radius, at 1.86 Earth radii, and Kepler-299 e the second-largest, at 1.87 Earth radii.