WASP-129 b
Astrophysical Synthesis & Habitability Characterization
WASP-129 b is a confirmed gas giant exoplanet orbiting the star WASP-129, located approximately 983.2 light-years (301.46 parsecs) from the Solar System. First announced in 2016 by SuperWASP-South using the Transit detection technique (producing an estimated primary transit depth of 1.1275% across the stellar disk), this world measures 10.424 Earth radii (0.93 Jupiter radii) and has a measured mass of 317.83 Earth masses (1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.55 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.93 g⊕ (28.73 m/s²), and an escape velocity of 61.8 km/s.
In its orbital architecture around WASP-129, WASP-129 b completes one full revolution every 5.748 Earth days at a semi-major axis of 0.0628 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 118.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.096 carries the world between 0.0568 AU at periapsis and 0.0688 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1100 K (+827°C / +1521°F) and receiving 345.72 S⊕ (~470,525 W/m²), WASP-129 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-129 is classified as a solar-type yellow star of spectral type G1 with an effective photospheric temperature of 5,900 K, a radius of 0.9 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 0.881 L☉. Stellar evolution modeling indicates an estimated stellar age of 1 Gyr and a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, WASP-129 shines at apparent V-band magnitude 12.179 (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-129 |
| Spectral Type | G1 |
| Effective Temp (Teff) | 5,900 K |
| Stellar Radius | 0.9000 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 0.881 L☉ |
| Metallicity [Fe/H] | 0.150 dex |
| Stellar Age | 1.000 Gyr |
| Apparent Magnitude | V: 12.179 · G: 11.813 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.062800 AU |
| Orbital Period | 5.748 days |
| Mean Orbital Velocity | 118.9 km/s |
| Orbital Eccentricity (e) | 0.09600 |
| Orbital Inclination (i) | 87.7000° |
| Mean Bulk Density | 1.55 g/cm³ (61.8 km/s vesc) |
| Insolation Flux | 345.7201 S⊕ (~470,525 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 983.200 LY (301.462 pc) |