HD 158259 and Its Five Known Planets

HD 158259 is a G0 star located 88.2 light-years away, with a reported mass of 1.04 solar masses, a radius of 1.26 solar radii, and a temperature of 5800 K. Its radius estimate is larger than the Sun's. Five planets are known to orbit this star, all discovered in 2020 by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Each of the five planets has a minimum mass larger than Earth's, meaning these are lower bounds on their true masses rather than exact values.

HD 158259 b has a minimum mass of 2.22 Earth masses and an orbital period of 2.18 days. HD 158259 c has a minimum mass of 5.6 Earth masses and an orbital period of 3.43 days. HD 158259 d has a minimum mass of 5.41 Earth masses and an orbital period of 5.2 days. HD 158259 e has a minimum mass of 6.08 Earth masses and an orbital period of 7.95 days. HD 158259 f has a minimum mass of 6.14 Earth masses and an orbital period of 12 days.

Among the listed planets, HD 158259 b has the shortest year by reported estimates, at 2.18 days, while HD 158259 f has the longest, at 12 days. HD 158259 c has the second-shortest year by reported estimates, at 3.43 days, and HD 158259 e has the second-longest, at 7.95 days. In minimum mass, HD 158259 b is the smallest among the listed planets at 2.22 Earth masses, and HD 158259 f is the largest at 6.14 Earth masses. HD 158259 d has the second-smallest minimum mass at 5.41 Earth masses, while HD 158259 e has the second-largest at 6.08 Earth masses.