GJ 1132 b
Astrophysical Synthesis & Habitability Characterization
GJ 1132 b is a confirmed terrestrial exoplanet orbiting the star GJ 1132, located approximately 41.1 light-years (12.61 parsecs) from the Solar System. First announced in 2015 by Cerro Tololo Inter-American Observatory using the Transit detection technique (producing an estimated primary transit depth of 0.2443% across the stellar disk), this world measures 1.192 Earth radii and has a measured mass of 1.837 Earth masses. Combining its mass and radius yields a mean bulk density of 5.98 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.29 g⊕ (12.65 m/s²), and an escape velocity of 13.9 km/s.
In its orbital architecture around GJ 1132, GJ 1132 b completes one full revolution every 1.629 Earth days at a semi-major axis of 0.0157 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 104.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0118 (ranging from 0.0155 AU at periapsis to 0.0159 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 584 K (+311°C / +592°F) and receiving 19.30 S⊕ (~26,267 W/m²), GJ 1132 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 1132 is classified as a low-mass red dwarf of spectral type M4.5 V with an effective photospheric temperature of 3,229 K, a radius of 0.2211 R☉, a mass of 0.1945 M☉, an estimated bolometric luminosity of 0.00477 L☉. Stellar evolution modeling indicates an estimated stellar age of 5 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, GJ 1132 shines at apparent V-band magnitude 13.68 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The GJ 1132 system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 1132 b sharing its stellar neighborhood alongside GJ 1132 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: Cerro Tololo Inter-American Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 1132 |
| Spectral Type | M4.5 V |
| Effective Temp (Teff) | 3,229 K |
| Stellar Radius | 0.2211 R☉ |
| Stellar Mass | 0.1945 M☉ |
| Bolometric Luminosity | 0.00477 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | 5.000 Gyr |
| Apparent Magnitude | V: 13.680 · G: 12.138 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.015700 AU |
| Orbital Period | 1.629 days |
| Mean Orbital Velocity | 104.9 km/s |
| Orbital Eccentricity (e) | 0.01180 |
| Orbital Inclination (i) | 88.1600° |
| Mean Bulk Density | 5.98 g/cm³ (13.9 km/s vesc) |
| Insolation Flux | 19.3000 S⊕ (~26,267 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 41.100 LY (12.613 pc) |