WASP-147 b
Astrophysical Synthesis & Habitability Characterization
WASP-147 b is a confirmed gas giant exoplanet orbiting the star WASP-147, located approximately 1422.4 light-years (436.1 parsecs) from the Solar System. First announced in 2018 by SuperWASP-South using the Transit detection technique (producing an estimated primary transit depth of 0.6429% across the stellar disk), this world measures 12.498 Earth radii (1.11 Jupiter radii) and has a measured mass of 87.403 Earth masses (0.27 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.56 g⊕ (5.49 m/s²), and an escape velocity of 29.6 km/s.
In its orbital architecture around WASP-147, WASP-147 b completes one full revolution every 4.603 Earth days at a semi-major axis of 0.0549 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 129.8 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1404 K (+1131°C / +2068°F) and receiving 639.49 S⊕ (~870,349 W/m²), WASP-147 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-147 is classified as a solar-type yellow star of spectral type G4 with an effective photospheric temperature of 5,702 K, a radius of 1.429 R☉, a mass of 1.044 M☉, an estimated bolometric luminosity of 1.937 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.47 Gyr and a metallicity of [Fe/H] = 0.092 dex (metal-rich relative to the Sun). From Earth, WASP-147 shines at apparent V-band magnitude 12.681 (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-147 |
| Spectral Type | G4 |
| Effective Temp (Teff) | 5,702 K |
| Stellar Radius | 1.4290 R☉ |
| Stellar Mass | 1.0440 M☉ |
| Bolometric Luminosity | 1.937 L☉ |
| Metallicity [Fe/H] | 0.092 dex |
| Stellar Age | 8.470 Gyr |
| Apparent Magnitude | V: 12.681 · G: 12.183 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.054900 AU |
| Orbital Period | 4.603 days |
| Mean Orbital Velocity | 129.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.9000° |
| Mean Bulk Density | 0.25 g/cm³ (29.6 km/s vesc) |
| Insolation Flux | 639.4923 S⊕ (~870,349 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1422.400 LY (436.098 pc) |