GJ 676 A and Its Four Planets

GJ 676 A is an M0 V star, a small, cool red dwarf, located 52.3 light-years away. Its reported mass estimate is 0.73 solar masses, its radius is 0.69 solar radii, and its temperature is 3730 K. Each of these values is smaller or cooler than the corresponding value for the Sun. Four planets have been reported orbiting this star.

GJ 676 A b was discovered in 2010 by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Its mass is 1840 Earth masses, roughly 5.79 times Jupiter's mass, and its orbital period is 1050 days. GJ 676 A c, also found by radial velocity, was discovered in 2016. Its mass is 4290 Earth masses, roughly 13.5 times Jupiter's mass, and its orbital period is 13900 days, the longest among these four planets.

The two remaining planets were both discovered in 2012 by radial velocity. GJ 676 A d has a minimum mass of 3.81 Earth masses and an orbital period of 3.6 days, the shortest among the listed planets. GJ 676 A e has a minimum mass of 6.67 Earth masses and an orbital period of 35.5 days. For both of these planets, the reported minimum mass is larger than Earth's, and the value represents a lower bound on the planet's true mass rather than an ordinary mass estimate.