WASP-126 b
Astrophysical Synthesis & Habitability Characterization
WASP-126 b is a confirmed gas giant exoplanet orbiting the star WASP-126, located approximately 706.2 light-years (216.53 parsecs) from the Solar System. First announced in 2016 by SuperWASP-South using the Transit detection technique (producing an estimated primary transit depth of 0.5761% across the stellar disk), this world measures 10.514 Earth radii (0.94 Jupiter radii) and has a measured mass of 90.3 Earth masses (0.28 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.43 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.82 g⊕ (8.04 m/s²), and an escape velocity of 32.8 km/s.
In its orbital architecture around WASP-126, WASP-126 b completes one full revolution every 3.289 Earth days at a semi-major axis of 0.0449 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 148.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.18 carries the world between 0.0368 AU at periapsis and 0.053 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1480 K (+1207°C / +2205°F) and receiving 759.34 S⊕ (~1,033,458 W/m²), WASP-126 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-126 is classified as a solar-type yellow star of spectral type G2 with an effective photospheric temperature of 5,800 K, a radius of 1.27 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.638 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.4 Gyr and a metallicity of [Fe/H] = 0.207 dex (metal-rich relative to the Sun). From Earth, WASP-126 shines at apparent V-band magnitude 10.994 (faint and requiring research-grade or CCD telescopic photometry) 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: SuperWASP-South · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-126 |
| Spectral Type | G2 |
| Effective Temp (Teff) | 5,800 K |
| Stellar Radius | 1.2700 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.638 L☉ |
| Metallicity [Fe/H] | 0.207 dex |
| Stellar Age | 6.400 Gyr |
| Apparent Magnitude | V: 10.994 · G: 11.067 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044900 AU |
| Orbital Period | 3.289 days |
| Mean Orbital Velocity | 148.5 km/s |
| Orbital Eccentricity (e) | 0.18000 |
| Orbital Inclination (i) | 89.5100° |
| Mean Bulk Density | 0.43 g/cm³ (32.8 km/s vesc) |
| Insolation Flux | 759.3374 S⊕ (~1,033,458 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 706.200 LY (216.526 pc) |