HD 164922 and Its Four Planets

HD 164922 is a K0V star located 71.8 light-years from Earth. The K designation places it in a cooler spectral class than the Sun, and the trailing V marks it as a main-sequence dwarf. Its reported mass is 0.93 solar masses and its reported radius is 0.94 solar radii, both smaller than the Sun's corresponding values. Its reported temperature is 5390 K, cooler than the Sun's. The star's age is given as 13.4 billion years.

Four planets have been reported orbiting this star: HD 164922 b, HD 164922 c, HD 164922 d, and HD 164922 e. All four were detected by the radial velocity method, which tracks the wobble a planet's gravity induces in its star's motion over repeated orbits. The four discoveries were announced in 2005, 2016, 2020, and 2021 respectively.

The minimum masses of the four planets span a wide range. HD 164922 b has a minimum mass of 116 Earth masses and an orbital period of 1210 days, the longest year among the listed planets. HD 164922 c has a minimum mass of 13 Earth masses and a period of 75.7 days. HD 164922 e has a minimum mass of 10.5 Earth masses and a period of 41.8 days, the second-shortest year among the listed planets. HD 164922 d has the smallest minimum mass at 4 Earth masses and the shortest year at 12.5 days. Each of the four minimum masses is larger than Earth's mass. Since these are minimum masses, they are lower bounds on the planets' true masses rather than exact values.