Kepler-226 and Its Three Planets

Kepler-226 is a star located 3200 light-years away, and three planets have been found orbiting it. The host star is 4.37 billion years old, with a mass of 0.89 solar masses and a radius of 0.85 solar radii. Its temperature is 5430 K, cooler than the Sun's, and both its reported mass and radius estimates are smaller than the Sun's.

The planets were all discovered by transit, the dimming of a star's brightness when a planet crosses in front of it from our viewpoint, with repeated dips helping establish orbital periods. All three were discovered in 2014 and have measured orbital periods and radii.

Kepler-226 b is a Super-Earth with an orbital period of 3.94 days and a radius of 1.55 Earth radii, the second-smallest radius among the listed planets and the shortest year by reported estimates. Kepler-226 c is also a Super-Earth, with an orbital period of 5.35 days and a radius of 2.27 Earth radii, larger than Earth's and the largest radius among the listed planets, with the second-shortest year. Kepler-226 d is Earth-like, with an orbital period of 8.11 days and a radius of 1.22 Earth radii, the smallest radius among the listed planets and the longest year by reported estimates. Under the size classes, an Earth-like planet stays within 1.5 times Earth's radius, while a Super-Earth reaches 2.5 times.