Kepler-656: A Cool Dwarf with Two Small Worlds

Kepler-656 is a star located 2900 light-years away, with two planets in orbit around it. The star's mass is 0.86 solar masses, its radius is 0.82 solar radii, and its temperature is 5280 K. Its mass and radius are smaller than the Sun's, and its temperature is cooler than the Sun's. Its age is 4.37 billion years.

Both planets were detected via the transit method, in which a planet crosses in front of its star and causes a slight, repeating dip in brightness. Kepler-656 b, discovered in 2016, is a Neptune-like planet with a radius of 3.12 Earth radii, larger than Earth's; it completes an orbit in 1.26 days, the shortest reported orbital period among the listed planets. Kepler-656 c, discovered in 2023, is an Earth-like planet with a radius of 1.41 Earth radii, larger than Earth's and the smallest radius among the listed planets; its orbital period is 5.25 days, the longest reported orbital period among the listed planets.