HIP 5158: A Cooler, Less Massive Star with Two Known Planets

HIP 5158 is a star located 168 light-years away, and two planets have been detected in orbit around it. The host star has a reported mass of 0.78 solar masses, making it less massive than the Sun, and a reported temperature of 4960 K, which is cooler than the Sun. Its age is given as a reported upper limit of 6 billion years.

HIP 5158 b was discovered in 2009 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion. HIP 5158 b has a minimum mass of 451 Earth masses, roughly 1.42 times Jupiter's mass, and an orbital period of 346 days, the shortest year among the listed planets by reported estimates.

HIP 5158 c was discovered in 2011, also by radial velocity. It has a minimum mass of 4780 Earth masses, roughly 15 times Jupiter's mass, and an orbital period of 9020 days, the longest year among the listed planets by reported estimates.

Among the listed planets, HIP 5158 b has the smallest minimum mass at 451 Earth masses, while HIP 5158 c has the largest at 4780 Earth masses. Both minimum masses are larger than Earth's.