Teegarden's Star is close to the smallest a star can be and still fuse hydrogen: a tenth of the Sun’s mass, radiating less than a thousandth of its light. It was missed by every survey until 2003. Three planets, all around an Earth mass, have since been found around it.
Fly there in 3DTeegarden b and c are the two highest-scoring planets on the Earth Similarity Index of anything found so far. That index compares size, density and temperature only - it says nothing about whether either has air, water, or a magnetic field, none of which has been measured.
Seen from Teegarden’s Star, the Solar System lies almost exactly edge-on: an observer there would watch Earth transit the Sun.
| Spectral type | M7 V |
| Surface temperature | 3,034 K |
| Mass | 0.097 solar masses |
| Radius | 0.12 solar radii |
| Luminosity | 0.000722 times the Sun |
| Apparent magnitude | 15.13 |
| Age | about 8 billion years |
| Distance from the Sun | 12.5 light-years (3.8 parsecs) |
| Position (J2000) | RA 43.2537°, Dec 16.8813° |
| Constellation | Aries |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| Teegarden's Star b | 4.91 days | 0.0259 AU | 1.05 R⊕ estimated | 1.16 M⊕ minimum | Radial Velocity, 2019 |
| Teegarden's Star c | 11.4 days | 0.0455 AU | 1.02 R⊕ estimated | 1.05 M⊕ minimum | Radial Velocity, 2019 |
| Teegarden's Star d | 26.1 days | 0.0791 AU | 0.954 R⊕ estimated | 0.82 M⊕ minimum | Radial Velocity, 2024 |
Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.