HD 164604 and Its Two Known Planets

HD 164604 is a K3.5 V star located 128 light-years away. Its spectral type marks it as a main-sequence dwarf, and it is the only star in its system. The star is 1.6 billion years old and has a mass of 0.77 solar masses, a radius of 0.78 solar radii, and a temperature of 4660 K. Its reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's. Two planets are known to orbit this host.

HD 164604 b was discovered in 2009 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion. It has a mass of 4200 Earth masses and an orbital period of 654 days. Its reported mass estimate is larger than Earth's and roughly 13.2 times Jupiter's mass. Among the listed planets, it has the shortest year by reported estimates and the largest reported mass.

HD 164604 c was discovered in 2026, also by radial velocity. It has a mass of 3020 Earth masses and an orbital period of 5390 days. Its reported mass estimate is larger than Earth's and roughly 9.5 times Jupiter's mass. Among the listed planets, it has the longest year by reported estimates and the smallest reported mass.