HD 134606 and Its Five Planets

HD 134606 is a G5IV star 87.4 light-years away with five planets orbiting it. A spectral type like G5IV classifies a star by temperature class and evolutionary state, so HD 134606 is a G-type star, the same broad class as the Sun. The star is 9.12 billion years old, with a mass of 1.06 solar masses and a radius of 1.12 solar radii, both larger than the Sun's reported values, while its temperature of 5650 K is cooler than the Sun's.

All five planets were discovered in 2024 using 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 134606 e has a minimum mass of 2.34 Earth masses and an orbital period of 4.32 days, the shortest among the listed planets. HD 134606 b has a minimum mass of 9.09 Earth masses and a period of 12.1 days, the second-shortest. HD 134606 f has a minimum mass of 5.63 Earth masses and a period of 26.9 days, the second-smallest minimum mass. HD 134606 c has a minimum mass of 11.3 Earth masses and a period of 58.9 days, the second-longest among the listed planets. HD 134606 d has a minimum mass of 44.8 Earth masses and a period of 967 days, the largest minimum mass and longest year among the listed planets. Each planet's minimum mass is larger than Earth's.

A minimum mass is a lower bound on a planet's true mass, so these figures represent the least mass each world could have. The orbital periods range from the brief 4.32-day orbit of HD 134606 e to the 967-day orbit of HD 134606 d.