HD 141399 and Its Four Planets

HD 141399 is a K0 V star 121 light-years away. Its spectral type marks it as a K-type main-sequence dwarf, a class cooler and redder than the Sun's G type, and its reported temperature of 5540 K is cooler than the Sun's. The star's reported radius estimate of 1.39 solar radii is larger than the Sun's, while its mass is 0.97 solar masses.

Four planets are known to orbit this star. All four were discovered in 2014 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. Each has a minimum mass, a lower bound on its true mass rather than an ordinary mass estimate.

HD 141399 b has a minimum mass of 143 Earth masses and an orbital period of 94.4 days, the shortest year among the listed planets. HD 141399 c has a minimum mass of 423 Earth masses, roughly 1.33 times Jupiter's mass, and an orbital period of 202 days, the second-shortest among the listed planets. HD 141399 d has a minimum mass of 375 Earth masses, roughly 1.18 times Jupiter's mass, and an orbital period of 1070 days, the second-longest among the listed planets. HD 141399 e has a minimum mass of 210 Earth masses and an orbital period of 5000 days, the longest year among the listed planets.

Among the listed planets, HD 141399 b has the smallest minimum mass, HD 141399 c has the largest, HD 141399 d has the second-largest, and HD 141399 e has the second-smallest.