HD 20794 and Its Four Known Planets

HD 20794 is a G8.0V star - a G-type, Sun-like main-sequence dwarf - located 19.6 light-years away. Its reported mass is 0.85 solar masses, its reported radius 0.92 solar radii, and its reported temperature 5400 K, all smaller or cooler than the Sun's corresponding values. The star is estimated to be 13.5 billion years old. Four planets have been reported orbiting this host, all detected by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion.

Two of the planets were announced in 2011. HD 20794 b has a minimum mass of 2.15 Earth masses and an orbital period of 18.3 days, while HD 20794 d has a minimum mass of 2.98 Earth masses and an orbital period of 89.7 days. HD 20794 e, announced in 2017, has a minimum mass of 4.77 Earth masses and an orbital period of 147 days. The most recently reported, HD 20794 f, was announced in 2025 with a minimum mass of 5.82 Earth masses and an orbital period of 648 days.

Each planet's minimum mass is larger than Earth's. Among the listed planets, HD 20794 b has the shortest year, at 18.3 days, and the smallest minimum mass, at 2.15 Earth masses. HD 20794 d has the second-shortest year, at 89.7 days, and the second-smallest minimum mass, at 2.98 Earth masses. HD 20794 e has the second-longest year, at 147 days, and the second-largest minimum mass, at 4.77 Earth masses. HD 20794 f has the longest year, at 648 days, and the largest minimum mass, at 5.82 Earth masses.