GJ 86 b
Astrophysical Synthesis & Habitability Characterization
GJ 86 b is a confirmed gas giant exoplanet orbiting the star GJ 86, located approximately 35.2 light-years (10.78 parsecs) from the Solar System. First announced in 1999 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.9 Earth radii (1.15 Jupiter radii) and has a measured mass of 1404.809 Earth masses (4.42 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.61 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 8.44 g⊕ (82.77 m/s²), and an escape velocity of 116.7 km/s.
In its orbital architecture around GJ 86, GJ 86 b completes one full revolution every 15.765 Earth days at a semi-major axis of 0.11 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 75.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.04 (ranging from 0.1056 AU at periapsis to 0.1144 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 661 K (+388°C / +730°F) and receiving 33.70 S⊕ (~45,872 W/m²), GJ 86 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 86 is classified as an orange K-type star of spectral type K1V with an effective photospheric temperature of 5,182 K, a radius of 0.77 R☉, a mass of 0.93 M☉, an estimated bolometric luminosity of 0.384 L☉. Stellar evolution modeling indicates an estimated stellar age of 11.3 Gyr and a metallicity of [Fe/H] = -0.22 dex (metal-poor relative to the Sun). From Earth, GJ 86 shines at apparent V-band magnitude 6.12 (visible to the unaided human eye under dark skies) in the Southern 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 86 |
| Spectral Type | K1V |
| Effective Temp (Teff) | 5,182 K |
| Stellar Radius | 0.7700 R☉ |
| Stellar Mass | 0.9300 M☉ |
| Bolometric Luminosity | 0.384 L☉ |
| Metallicity [Fe/H] | -0.220 dex |
| Stellar Age | 11.300 Gyr |
| Apparent Magnitude | V: 6.120 · G: 5.885 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.110000 AU |
| Orbital Period | 15.765 days |
| Mean Orbital Velocity | 75.9 km/s |
| Orbital Eccentricity (e) | 0.04000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.61 g/cm³ (116.7 km/s vesc) |
| Insolation Flux | 33.7048 S⊕ (~45,872 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 35.200 LY (10.784 pc) |