Kepler-194 and Its Three Planets

Kepler-194 is a star located 3580 light-years away. It hosts three planets, all discovered by transit in 2014. The star is 3.55 billion years old and has a mass of 1.09 solar masses, a radius of 1.11 solar radii, and a temperature of 5970 K. Its reported mass estimate is larger than the Sun's, and its reported temperature is hotter than the Sun's. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness; repeated dips help establish orbital periods.

Kepler-194 b is a Super-Earth with an orbital period of 2.09 days and a radius of 1.51 Earth radii. Among the listed planets, it has the shortest year by reported estimates and the smallest radius by reported estimates. Kepler-194 c is a Neptune-like planet with an orbital period of 17.3 days and a radius of 2.59 Earth radii. Among the listed planets, it has the second-shortest year and the largest radius by reported estimates. Its reported radius estimate is larger than Earth's. Planet size classes compare radius with Earth's: a Super-Earth reaches 2.5 times Earth's radius, and a Neptune-like planet reaches 4 times Earth's radius.

Kepler-194 d is a Super-Earth with an orbital period of 52.8 days and a radius of 2.4 Earth radii. Among the listed planets, it has the longest year and the second-smallest radius by reported estimates. Its reported radius estimate is larger than Earth's.