GJ 806 b
Astrophysical Synthesis & Habitability Characterization
GJ 806 b is a confirmed super-earth exoplanet orbiting the star GJ 806, located approximately 39.3 light-years (12.05 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0867% across the stellar disk), this world measures 1.331 Earth radii and has a measured mass of 1.9 Earth masses. Combining its mass and radius yields a mean bulk density of 4.44 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 13.4 km/s.
In its orbital architecture around GJ 806, GJ 806 b completes one full revolution every 0.926 Earth days at a semi-major axis of 0.01406 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 165.1 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 940 K (+667°C / +1233°F) and receiving 130.00 S⊕ (~176,930 W/m²), GJ 806 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 806 is classified as a low-mass red dwarf of spectral type M1.5 V with an effective photospheric temperature of 3,600 K, a radius of 0.4144 R☉, a mass of 0.413 M☉, an estimated bolometric luminosity of 0.026 L☉. Stellar evolution modeling indicates an estimated stellar age of 5 Gyr and a metallicity of [Fe/H] = -0.28 dex (metal-poor relative to the Sun). From Earth, GJ 806 shines at apparent V-band magnitude 10.79 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The GJ 806 system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 806 b sharing its stellar neighborhood alongside GJ 806 c.
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 | GJ 806 |
| Spectral Type | M1.5 V |
| Effective Temp (Teff) | 3,600 K |
| Stellar Radius | 0.4144 R☉ |
| Stellar Mass | 0.4130 M☉ |
| Bolometric Luminosity | 0.026 L☉ |
| Metallicity [Fe/H] | -0.280 dex |
| Stellar Age | 5.000 Gyr |
| Apparent Magnitude | V: 10.790 · G: 9.825 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.014060 AU |
| Orbital Period | 0.926 days |
| Mean Orbital Velocity | 165.1 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.7000° |
| Mean Bulk Density | 4.44 g/cm³ (13.4 km/s vesc) |
| Insolation Flux | 130.0000 S⊕ (~176,930 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 39.300 LY (12.045 pc) |