Kepler-56: A Distant Star With Three Known Planets

Kepler-56 is a star located 2980 light-years away, and three planets have been found orbiting it. The star is estimated to be 3.5 billion years old, with a mass of 1.32 solar masses and a radius of 4.23 solar radii. Its temperature is 4840 K. Its reported mass and radius estimates are larger than the Sun’s, while its reported temperature is cooler than the Sun’s.

Kepler-56 b and Kepler-56 c are both Jupiter-like planets discovered by the transit method in 2012. Kepler-56 b has a mass of 22.1 Earth masses, a radius of 6.51 Earth radii, and an orbital period of 10.5 days. Its reported mass and radius estimates are larger than Earth’s, and its mean density is 0.441 g/cm³, 0.0801 times Earth's. Kepler-56 c has a mass of 181 Earth masses, a radius of 9.8 Earth radii, and an orbital period of 21.4 days. Its reported mass and radius estimates are also larger than Earth’s, and its mean density is 1.06 g/cm³, 0.192 times Earth's. Among the listed planets, Kepler-56 b has the shortest year by reported estimates, at 10.5 days, and Kepler-56 c has the second-shortest, at 21.4 days.

Kepler-56 d was discovered by radial velocity in 2016. Its minimum mass is 1780 Earth masses, and its orbital period is 1000 days. Its minimum mass is larger than Earth’s and roughly 5.61 times Jupiter’s mass. Among the listed planets, Kepler-56 d has the longest year by reported estimates, at 1000 days.