GJ 9689 and Its Lone Known Planet

GJ 9689 is an M0.5 star, a small, cool red dwarf, located 99.9 light-years away. Its spectral class places it among the cooler, redder stars, and its reported temperature of 3840 K is cooler than the Sun's. The star's reported mass estimate is 0.59 solar masses, smaller than the Sun's, and its reported radius estimate is 0.57 solar radii, also smaller than the Sun's. Its age is given as 8.9 billion years. One planet has been reported orbiting this host.

That planet is GJ 9689 b, discovered in 2020 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion. Its minimum mass is 9.65 Earth masses, a lower bound on its true mass and larger than Earth's. Its orbital period is 18.3 days.