Kepler-19: A Star with Three Known Planets

Kepler-19 is a star located 713 light-years away, and it hosts three known planets. The star is estimated to be 1.9 billion years old, with a mass of 0.936 solar masses and a radius of 0.85 solar radii. Its reported temperature is 5540 K. The star's reported mass estimate is smaller than the Sun's, its reported radius estimate is smaller than the Sun's, and its reported temperature is cooler than the Sun's.

Kepler-19 b was discovered in 2011 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it. Kepler-19 b is classified as a Super-Earth, with a radius of 2.21 Earth radii and a mass of 6.1 Earth masses. Its orbital period is 9.29 days. Among the listed planets, Kepler-19 b has the shortest year and the smallest reported mass. Its mean density is 3.12 g/cm³, 0.566 times Earth's.

Kepler-19 c was also discovered in 2011, by the transit timing variations method. It has a mass of 13.1 Earth masses and an orbital period of 28.7 days. Among the listed planets, Kepler-19 c has the second-shortest year and the second-smallest reported mass.

Kepler-19 d was discovered in 2017 using the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. This planet has a mass of 22.5 Earth masses and an orbital period of 63 days. Among the listed planets, Kepler-19 d has the longest year and the largest reported mass.

The reported masses of all three planets are larger than Earth's, and Kepler-19 b's reported radius is also larger than Earth's.