WASP-33 b
Astrophysical Synthesis & Habitability Characterization
WASP-33 b is a confirmed gas giant exoplanet orbiting the star WASP-33, located approximately 397.7 light-years (121.94 parsecs) from the Solar System. First announced in 2010 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 1.2852% across the stellar disk), this world measures 17.856 Earth radii (1.59 Jupiter radii) and has a measured mass of 665.218 Earth masses (2.09 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.64 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.09 g⊕ (20.5 m/s²), and an escape velocity of 68.3 km/s.
In its orbital architecture around WASP-33, WASP-33 b completes one full revolution every 1.22 Earth days at a semi-major axis of 0.0239 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 213.1 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 2782 K (+2509°C / +4548°F) and receiving 9,392.05 S⊕ (~12,782,576 W/m²), WASP-33 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-33 is classified as a luminous A-type star of spectral type A with an effective photospheric temperature of 7,430 K, a radius of 1.444 R☉, a mass of 1.495 M☉, an estimated bolometric luminosity of 5.701 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, WASP-33 shines at apparent V-band magnitude 8.14 (accessible to binoculars and small amateur telescopes) in the Northern 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-33 |
| Spectral Type | A |
| Effective Temp (Teff) | 7,430 K |
| Stellar Radius | 1.4440 R☉ |
| Stellar Mass | 1.4950 M☉ |
| Bolometric Luminosity | 5.701 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.140 · G: 8.070 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.023900 AU |
| Orbital Period | 1.22 days |
| Mean Orbital Velocity | 213.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.6300° |
| Mean Bulk Density | 0.64 g/cm³ (68.3 km/s vesc) |
| Insolation Flux | 9392.0471 S⊕ (~12,782,576 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 397.700 LY (121.944 pc) |