Kepler-394: A Star and Its Three Super-Earths

Kepler-394 is a star located 3,450 light-years away, with three planets orbiting it. All three were detected by the transit method, in which a planet passes in front of its star from our viewpoint and causes a small dip in observed brightness; repeated dips help establish orbital periods. The star's reported mass estimate is 1.13 solar masses and its reported radius estimate is 1.21 solar radii, both larger than the Sun's. Its reported temperature is 6,120 K, hotter than the Sun's, and its age is 3.24 billion years.

The three planets are all classified as Super-Earths, a size class that reaches 2.5 times Earth's radius. Kepler-394 d was discovered in 2021. It has an orbital period of 5.61 days, the shortest among the listed planets, and a radius of 1.5 Earth radii, the smallest of the three. Kepler-394 b, discovered in 2014, has an orbital period of 8.01 days, the second-shortest among the listed planets, and a radius of 1.6 Earth radii, the second-smallest.

Kepler-394 c, also discovered in 2014, has an orbital period of 12.1 days, the longest among the listed planets, and a radius of 1.66 Earth radii, the largest of the three. That radius is larger than Earth's.