Kepler-261: A Cool, Older Star With Two Super-Earths

Kepler-261 is a star located 1040 light-years away, and two planets have been found orbiting it. The host star is 3.98 billion years old, with a mass of 0.85 solar masses and a radius of 0.8 solar radii, making both its reported mass and radius estimates smaller than the Sun's. Its temperature is 5140 K, cooler than the Sun's.

Both planets were discovered by transit in 2014. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness. Kepler-261 b is a Super-Earth with an orbital period of 10.4 days and a radius of 2.18 Earth radii. Among the listed planets, it has the shortest year and the largest radius. Kepler-261 c is also a Super-Earth, with an orbital period of 24.6 days and a radius of 2 Earth radii. It has the longest year and the smallest radius among the listed planets. Both planets' reported radius estimates are larger than Earth's.