WASP-54 b
Astrophysical Synthesis & Habitability Characterization
WASP-54 b is a confirmed gas giant exoplanet orbiting the star WASP-54, located approximately 819.6 light-years (251.3 parsecs) from the Solar System. First announced in 2012 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.851% across the stellar disk), this world measures 17.71 Earth radii (1.58 Jupiter radii) and has a measured mass of 187.52 Earth masses (0.59 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.19 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.6 g⊕ (5.88 m/s²), and an escape velocity of 36.4 km/s.
In its orbital architecture around WASP-54, WASP-54 b completes one full revolution every 3.694 Earth days at a semi-major axis of 0.04988 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 146.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 0.0464 AU at periapsis and 0.0534 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1759 K (+1486°C / +2707°F) and receiving 1,639.11 S⊕ (~2,230,825 W/m²), WASP-54 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-54 is classified as a warm F-type star of spectral type F9 with an effective photospheric temperature of 6,100 K, a radius of 1.76 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 3.848 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.9 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, WASP-54 shines at apparent V-band magnitude 10.413 (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-54 |
| Spectral Type | F9 |
| Effective Temp (Teff) | 6,100 K |
| Stellar Radius | 1.7600 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 3.848 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 6.900 Gyr |
| Apparent Magnitude | V: 10.413 · G: 10.244 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.049880 AU |
| Orbital Period | 3.694 days |
| Mean Orbital Velocity | 146.9 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | 84.9700° |
| Mean Bulk Density | 0.19 g/cm³ (36.4 km/s vesc) |
| Insolation Flux | 1639.1072 S⊕ (~2,230,825 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 819.600 LY (251.303 pc) |