HD 219134: A Nearby K-Type Dwarf and Its Six Planets

HD 219134 is a K3.0V star located 21.3 light-years away, hosting six planets in this catalog. The star is 12.5 billion years old, with a mass of 0.79 solar masses and a radius of 0.77 solar radii. Its temperature is 4840 K, cooler than the Sun's.

The six planets were all discovered in 2015 through the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. HD 219134 b and HD 219134 c are both Super-Earths. HD 219134 b has a mass of 4.74 Earth masses, a radius of 1.6 Earth radii, and an orbital period of 3.09 days, the shortest year among the listed planets. HD 219134 c has a mass of 4.36 Earth masses, a radius of 1.51 Earth radii, and an orbital period of 6.76 days, the second-shortest year among the listed planets. Both planets' reported mass and radius estimates are larger than Earth's. HD 219134 b has a mean density of 6.35 g/cm³, 1.15 times Earth's, while HD 219134 c's is 6.96 g/cm³, 1.26 times Earth's.

HD 219134 d orbits every 46.9 days, with a reported lower limit of 16.17 Earth masses and a reported lower limit of 1.61 Earth radii. HD 219134 f orbits every 22.7 days, with a reported lower limit of 7.3 Earth masses and a reported lower limit of 1.31 Earth radii. HD 219134 g has a minimum mass of 10.8 Earth masses and an orbital period of 94.2 days, the second-longest year among the listed planets; its minimum mass is larger than Earth's. HD 219134 h has a minimum mass of 108 Earth masses and an orbital period of 2250 days, the longest year among the listed planets; its minimum mass is larger than Earth's.