Teegarden's Star: A Nearby Red Dwarf With Three Known Planets

Teegarden's Star is an M7.0 V star located 12.5 light-years away. Its spectral type marks it as a small, cool red dwarf. Its reported mass is 0.089 solar masses, its reported radius is 0.107 solar radii, and its reported temperature is 2900 K. All three of these estimates are smaller or cooler than the corresponding values for the Sun. The star's age is given as a reported lower limit of 8 billion years. Astronomers have identified three planets orbiting this host: Teegarden's Star b, Teegarden's Star c, and Teegarden's Star d.

All three planets were found using the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion; repeated wobbles reveal the planet and its orbital period. Teegarden's Star b and Teegarden's Star c were both discovered in 2019, while Teegarden's Star d was discovered in 2024.

Teegarden's Star b has a minimum mass of 1.16 Earth masses and an orbital period of 4.91 days. Its minimum mass is larger than Earth's, and among the listed planets it has both the largest minimum mass and the shortest year by reported estimates. Teegarden's Star c has a minimum mass of 1.05 Earth masses and an orbital period of 11.4 days; among the listed planets it has the second-smallest minimum mass and the second-shortest year by reported estimates. Teegarden's Star d has a minimum mass of 0.82 Earth masses and an orbital period of 26.1 days. Its minimum mass is smaller than Earth's, and among the listed planets it has the smallest minimum mass and the longest year by reported estimates.