GJ 3473 and Its Two Known Planets

GJ 3473 is an M4 spectral type star, a small, cool red dwarf, located 89.3 light-years away. Its reported mass is 0.36 solar masses, its radius is 0.364 solar radii, and its temperature is 3350 K, all smaller or cooler than the Sun's corresponding values. Two planets are known to orbit this star.

The planet GJ 3473 b was discovered in 2020 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it from our viewpoint. It is classified as Earth-like, with a radius of 1.26 Earth radii and a mass of 1.86 Earth masses, both larger than Earth's. Its mean density is 5.07 g/cm³, 0.921 times Earth's. It completes an orbit in 1.2 days, the shortest year among the listed planets.

The planet GJ 3473 c was also discovered in 2020, using the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Its minimum mass is 7.41 Earth masses, larger than Earth's, and its orbital period is 15.5 days, the longest year among the listed planets.