Teegarden's Star b
Astrophysical Synthesis & Habitability Characterization
Teegarden's Star b is a confirmed terrestrial exoplanet orbiting the star Teegarden's Star, located approximately 12.5 light-years (3.83 parsecs) from the Solar System. First announced in 2019 by Calar Alto Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 1.05 Earth radii and has a measured mass of 1.16 Earth masses. Combining its mass and radius yields a mean bulk density of 5.53 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 11.8 km/s.
In its orbital architecture around Teegarden's Star, Teegarden's Star b completes one full revolution every 4.906 Earth days at a semi-major axis of 0.0259 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 57.4 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.03 (ranging from 0.0251 AU at periapsis to 0.0267 AU at apoapsis), the planet experiences minimal orbital distance variation.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 277 K (+4°C / +39°F) and an incident stellar irradiance of 1.08 S⊕ (~1,470 W/m²), Teegarden's Star b orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
The host star Teegarden's Star is classified as a low-mass red dwarf of spectral type M7.0 V with an effective photospheric temperature of 3,034 K, a radius of 0.12 R☉, a mass of 0.097 M☉, an estimated bolometric luminosity of 0.00109 L☉. Stellar evolution modeling indicates an estimated stellar age of 8 Gyr and a metallicity of [Fe/H] = -0.11 dex (metal-poor relative to the Sun). From Earth, Teegarden's Star shines at apparent V-band magnitude 15.13 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Teegarden's Star system is a multi-planet architecture hosting 3 confirmed worlds, with Teegarden's Star b sharing its stellar neighborhood alongside Teegarden's Star c, Teegarden's Star d.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Calar Alto Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Teegarden's Star |
| Spectral Type | M7.0 V |
| Effective Temp (Teff) | 3,034 K |
| Stellar Radius | 0.1200 R☉ |
| Stellar Mass | 0.0970 M☉ |
| Bolometric Luminosity | 0.00109 L☉ |
| Metallicity [Fe/H] | -0.110 dex |
| Stellar Age | 8.000 Gyr |
| Apparent Magnitude | V: 15.130 · G: 12.275 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.025900 AU |
| Orbital Period | 4.906 days |
| Mean Orbital Velocity | 57.4 km/s |
| Orbital Eccentricity (e) | 0.03000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.53 g/cm³ (11.8 km/s vesc) |
| Insolation Flux | 1.0800 S⊕ (~1,470 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 12.500 LY (3.831 pc) |