HD 31527 and Its Three Worlds

HD 31527 is a G2 V star located 125 light-years from Earth. Its spectral type marks it as a Sun-like, main-sequence dwarf. The star is somewhat larger and more massive than the Sun, with a radius of 1.08 solar radii and a mass of 1.07 solar masses, and its temperature of 5910 K makes it hotter than the Sun. Three planets orbit this star, all discovered in 2019 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion.

HD 31527 b has a minimum mass of 10.5 Earth masses and an orbital period of 16.6 days. HD 31527 c has a minimum mass of 14.2 Earth masses and a period of 51.2 days, while HD 31527 d takes 272 days to complete an orbit and has a minimum mass of 11.8 Earth masses. Each minimum mass is a lower bound on the planet's true mass, and all three exceed Earth's mass.

Among the listed planets, HD 31527 b has the shortest year at 16.6 days, HD 31527 c has the second-shortest year at 51.2 days, and HD 31527 d has the longest year at 272 days. HD 31527 b also has the smallest minimum mass of the three, while HD 31527 c has the largest; HD 31527 d has the second-smallest minimum mass.