Gliese 12 b
Astrophysical Synthesis & Habitability Characterization
Gliese 12 b is a confirmed terrestrial exoplanet orbiting the star Gliese 12, located approximately 39.8 light-years (12.21 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1035% across the stellar disk), this world measures 0.93 Earth radii and has a measured mass of 0.95 Earth masses. Combining its mass and radius yields a mean bulk density of 6.51 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 11.3 km/s.
In its orbital architecture around Gliese 12, Gliese 12 b completes one full revolution every 12.761 Earth days at a semi-major axis of 0.067 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 57.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 0.0509 AU at periapsis and 0.0831 AU at apoapsis, driving measurable seasonal insolation cycles.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 315 K (+42°C / +108°F) and an incident stellar irradiance of 1.62 S⊕ (~2,205 W/m²), Gliese 12 b orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
The host star Gliese 12 is classified as a low-mass red dwarf of spectral type M4 V with an effective photospheric temperature of 3,328 K, a radius of 0.265 R☉, a mass of 0.255 M☉, an estimated bolometric luminosity of 0.00773 L☉. Stellar evolution modeling indicates an estimated stellar age of 7 Gyr and a metallicity of [Fe/H] = -0.24 dex (metal-poor relative to the Sun). From Earth, Gliese 12 shines at apparent V-band magnitude 12.6 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Gliese 12 |
| Spectral Type | M4 V |
| Effective Temp (Teff) | 3,328 K |
| Stellar Radius | 0.2650 R☉ |
| Stellar Mass | 0.2550 M☉ |
| Bolometric Luminosity | 0.00773 L☉ |
| Metallicity [Fe/H] | -0.240 dex |
| Stellar Age | 7.000 Gyr |
| Apparent Magnitude | V: 12.600 · G: 11.396 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.067000 AU |
| Orbital Period | 12.761 days |
| Mean Orbital Velocity | 57.1 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | 89.2500° |
| Mean Bulk Density | 6.51 g/cm³ (11.3 km/s vesc) |
| Insolation Flux | 1.6200 S⊕ (~2,205 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 39.800 LY (12.210 pc) |