WASP-117 b
Astrophysical Synthesis & Habitability Characterization
WASP-117 b is a confirmed gas giant exoplanet orbiting the star WASP-117, located approximately 515.2 light-years (157.96 parsecs) from the Solar System. First announced in 2014 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.7973% across the stellar disk), this world measures 11.882 Earth radii (1.06 Jupiter radii) and has a measured mass of 95.349 Earth masses (0.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.31 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.68 g⊕ (6.67 m/s²), and an escape velocity of 31.7 km/s.
In its orbital architecture around WASP-117, WASP-117 b completes one full revolution every 10.022 Earth days at a semi-major axis of 0.09459 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.3, swinging from 0.0662 AU at periapsis out to 0.123 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1001 K (+728°C / +1342°F) and receiving 706.39 S⊕ (~961,401 W/m²), WASP-117 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-117 is classified as a warm F-type star of spectral type F9 with an effective photospheric temperature of 6,040 K, a radius of 1.22 R☉, a mass of 1.29 M☉, an estimated bolometric luminosity of 1.777 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.6 Gyr and a metallicity of [Fe/H] = -0.11 dex (metal-poor relative to the Sun). From Earth, WASP-117 shines at apparent V-band magnitude 10.139 (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 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-117 |
| Spectral Type | F9 |
| Effective Temp (Teff) | 6,040 K |
| Stellar Radius | 1.2200 R☉ |
| Stellar Mass | 1.2900 M☉ |
| Bolometric Luminosity | 1.777 L☉ |
| Metallicity [Fe/H] | -0.110 dex |
| Stellar Age | 4.600 Gyr |
| Apparent Magnitude | V: 10.139 · G: 10.027 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.094590 AU |
| Orbital Period | 10.022 days |
| Mean Orbital Velocity | 102.7 km/s |
| Orbital Eccentricity (e) | 0.30000 |
| Orbital Inclination (i) | 89.1400° |
| Mean Bulk Density | 0.31 g/cm³ (31.7 km/s vesc) |
| Insolation Flux | 706.3929 S⊕ (~961,401 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 515.200 LY (157.963 pc) |