GJ 508.2 and Its Planet

GJ 508.2 is an M1.0 V star, a cool red dwarf, located 54.3 light-years away. Its mass is 0.54 solar masses, its radius is 0.53 solar radii, and its temperature is 3720 K. Each of these is smaller or cooler than the corresponding value for the Sun. The star hosts one known planet, GJ 508.2 b.

GJ 508.2 b was discovered in 2025 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion. Its minimum mass is a reported lower limit of 587.98255295 Earth masses, meaning its true mass could be higher. Its orbital period is a reported lower limit of 5300 days, so it takes at least that long to complete one orbit. No further measurements of the planet are reported.