KOI-12: A Distant Star With Two Known Planets

KOI-12 is a star located 1,300 light-years away, and two planets have been found orbiting it. The star is 1.5 billion years old and has a mass of 1.45 solar masses and a radius of 1.63 solar radii. Its temperature is 6820 K. The star's reported mass estimate, radius estimate, and temperature are all larger or hotter than the Sun's.

The two planets differ greatly in their orbits and masses. KOI-12 b was discovered in 2015 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it from our viewpoint. It is a Jupiter-like planet, meaning its radius exceeds 4 times Earth's radius, and it has a radius of 13.8 Earth radii and a mass of 350 Earth masses, both larger than Earth's. Its mean density is 0.735 g/cm³, 0.133 times Earth's. KOI-12 b completes an orbit every 17.9 days.

Kepler-448 c was discovered in 2017 by transit timing variations. Its mass is 6990 Earth masses, larger than Earth's and roughly 22 times Jupiter's mass. It takes 2500 days to complete one orbit.

Among the listed planets, KOI-12 b has the shortest year, at 17.9 days, while Kepler-448 c has the longest, at 2500 days. KOI-12 b also has the smallest reported mass, at 350 Earth masses, and Kepler-448 c has the largest, at 6990 Earth masses.