Kepler-11: A Six-Planet System in Transit

Kepler-11 is a star located 2110 light-years away. It has 0.95 solar masses, 1.1 solar radii, a temperature of 5680 K, and an age of 8 billion years. Six planets are known to orbit it: Kepler-11 b, c, d, e, f, and g. All six were discovered by the transit method in 2010, which means they were detected as they passed in front of the star and dimmed its light. Repeated dips of this kind help establish orbital periods.

Kepler-11 b is a Super-Earth with a mass of 1.9 Earth masses, a radius of 1.8 Earth radii, and an orbital period of 10.3 days. Among the listed planets, it has the shortest year, and its radius is the smallest. Kepler-11 c is Neptune-like, with a mass of 2.9 Earth masses, a radius of 2.87 Earth radii, and an orbital period of 13 days, the second-shortest year among the listed planets.

Kepler-11 d is Neptune-like with a mass of 7.3 Earth masses, a radius of 3.12 Earth radii, and an orbital period of 22.7 days. Kepler-11 e is Jupiter-like with a mass of 8 Earth masses, a radius of 4.19 Earth radii, and an orbital period of 32 days; that radius is the largest among the listed planets. Kepler-11 f is a Super-Earth with a mass of 2 Earth masses, a radius of 2.49 Earth radii, and an orbital period of 46.7 days, the second-longest year among the listed planets and the second-smallest radius. Kepler-11 g is Neptune-like, with an orbital period of 118 days, the longest year among the listed planets, and a radius of 3.33 Earth radii, the second-largest. Its mass is a reported upper limit of 25 Earth masses.