Barnard's Star and Its Four Known Planets

Barnard's star is a red dwarf of spectral type M3.5-4 V located 5.96 light-years away. Its reported mass is 0.162 solar masses, its radius is 0.185 solar radii, and its temperature is 3200 K. Each of these values is smaller or cooler than the Sun's corresponding figure. The star hosts four known planets, all discovered by the radial velocity method and all with minimum masses smaller than Earth's.

Barnard b was discovered in 2024. Its minimum mass is 0.299 Earth masses, and its orbital period is 3.15 days, the second-shortest year among these planets. Barnard c, found in 2025, has a minimum mass of 0.335 Earth masses and an orbital period of 4.12 days, the second-longest year here. Barnard d, also discovered in 2025, has the shortest year among the four at 2.34 days and a minimum mass of 0.263 Earth masses, the second-smallest among the group. Barnard e, discovered in 2025 as well, has the smallest minimum mass at 0.193 Earth masses and the longest year at 6.74 days.

A minimum mass is a lower bound on a planet's true mass, so the actual masses of these worlds remain higher than the figures given. The radial velocity technique detects such planets by measuring the wobble their gravity induces in the star's motion. Barnard c has the largest minimum mass of the four, while Barnard e's orbital period of 6.74 days is the longest recorded among them.