K2-31 b: A Distant Jupiter-Like World

K2-31 is a G7 V star located 360 light-years away. Its reported mass estimate is smaller than the Sun's, at 0.91 solar masses, and its reported radius estimate is also smaller than the Sun's, at 0.78 solar radii. The star's reported temperature of 5280 K is cooler than the Sun's. One planet orbits this host: K2-31 b.

K2-31 b is a Jupiter-like planet, a size class that exceeds 4 times Earth's radius. Discovered by transit in 2016, it has a reported radius estimate of 11.9 Earth radii, larger than Earth's. Its mass estimate is 564 Earth masses, larger than Earth's and roughly 1.77 times Jupiter's mass. The planet completes its orbit in 1.26 days, and its mean density is 1.85 g/cm³, 0.336 times Earth's. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness; repeated dips help establish orbital periods.