HD 28471 and Its Three Planets

HD 28471 is a star located 142 light-years away. Its spectral type, G5 V, marks it as a G-type main-sequence dwarf, the same broad class as the Sun. The star is estimated to be 6.56 billion years old, with a mass of 0.98 solar masses, a radius of 1.08 solar radii, and a temperature of 5770 K. Its reported radius estimate is larger than the Sun's. Three planets are known to orbit this host.

HD 28471 b was discovered in 2025 by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Repeated wobbles reveal the planet and its orbital period. HD 28471 b has a minimum mass of 3.72 Earth masses and an orbital period of 3.16 days, the shortest among the listed planets. Its minimum mass is also the smallest among them.

HD 28471 c has an orbital period of 6.12 days. It has a minimum mass of 5.72 Earth masses, the largest among the listed planets, and the second-shortest period. HD 28471 d has an orbital period of 11.7 days, the longest among the listed planets. Its minimum mass is 4.91 Earth masses, the second-smallest. All three planets have minimum masses larger than Earth's; each is a lower bound on the planet's true mass rather than an exact value.