The Kepler-342 System: A Distant Star With Four Small Worlds

Kepler-342 is a star located 2550 light-years from Earth. It has an age of 2.04 billion years, a mass of 1.26 solar masses and a radius of 1.34 solar radii. Its reported temperature is 6370 K, which is hotter than the Sun's. The star's reported mass and radius estimates are both larger than the Sun's. Four planets are known to orbit this host.

All four planets were found 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 planets orbit in 15.2 days, 26.2 days, 39.5 days and 1.64 days respectively.

Kepler-342 b, c and d are all Super-Earths, a size class that reaches 2.5 times Earth's radius. Their reported radii are 2.25 Earth radii, 1.96 Earth radii and 2.49 Earth radii, each larger than Earth's. Kepler-342 e is a Sub-Earth, meaning it is smaller than Earth, with a reported radius of 0.88 Earth radii that is smaller than Earth's. Among the listed planets, Kepler-342 d has the largest radius, Kepler-342 b the second-largest, Kepler-342 c the second-smallest and Kepler-342 e the smallest.

The orbital periods of the four planets range widely. Among the listed planets, Kepler-342 e has the shortest year, at 1.64 days, while Kepler-342 d has the longest, at 39.5 days. Kepler-342 b has the second-shortest year, at 15.2 days, and Kepler-342 c the second-longest, at 26.2 days.

Kepler-342 b and c were discovered in 2014, and Kepler-342 d followed the same year. Kepler-342 e was discovered in 2016.