About this world
Teegarden's Star d is an Earth-sized planet orbiting Teegarden's Star, a cool red dwarf (type M7.0V) 12.5 light-years from Earth. It is about 0.95 times the size of Earth (its size estimated from its mass), with at least 0.82 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 26.1 days at 0.079 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 159 K (−114 °C): too cold for liquid water on its surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2024 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. Teegarden's Star has 3 known planets; the others are Teegarden's Star b and Teegarden's Star c.