GJ 832 b
Astrophysical Synthesis & Habitability Characterization
GJ 832 b is a confirmed gas giant exoplanet orbiting the star GJ 832, located approximately 16.2 light-years (4.96 parsecs) from the Solar System. First announced in 2008 by Anglo-Australian Telescope using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.8 Earth radii (1.23 Jupiter radii) and has a measured mass of 314.65 Earth masses (0.99 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.66 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.65 g⊕ (16.18 m/s²), and an escape velocity of 53.4 km/s.
In its orbital architecture around GJ 832, GJ 832 b completes one full revolution every 3853 Earth days (10.55Julian years) at a semi-major axis of 3.7 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 10.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.05 carries the world between 3.515 AU at periapsis and 3.885 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 58 K (-215°C / -355°F) and an incident flux of 0.00 S⊕ (~3 W/m²), surface water and volatile species on GJ 832 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star GJ 832 is classified as a low-mass red dwarf of spectral type M2/3 V with an effective photospheric temperature of 3,472 K, a radius of 0.4416 R☉, a mass of 0.45 M☉, an estimated bolometric luminosity of 0.025 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.1 Gyr and a metallicity of [Fe/H] = -0.3 dex (metal-poor relative to the Sun). From Earth, GJ 832 shines at apparent V-band magnitude 8.66 (accessible to binoculars and small amateur telescopes) 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: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 832 |
| Spectral Type | M2/3 V |
| Effective Temp (Teff) | 3,472 K |
| Stellar Radius | 0.4416 R☉ |
| Stellar Mass | 0.4500 M☉ |
| Bolometric Luminosity | 0.025 L☉ |
| Metallicity [Fe/H] | -0.300 dex |
| Stellar Age | 8.100 Gyr |
| Apparent Magnitude | V: 8.660 · G: 7.738 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 3.700000 AU |
| Orbital Period | 3853 days |
| Mean Orbital Velocity | 10.4 km/s |
| Orbital Eccentricity (e) | 0.05000 |
| Orbital Inclination (i) | 51.0000° |
| Mean Bulk Density | 0.66 g/cm³ (53.4 km/s vesc) |
| Insolation Flux | 0.0019 S⊕ (~3 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 16.200 LY (4.964 pc) |