WASP-133 b
Astrophysical Synthesis & Habitability Characterization
WASP-133 b is a confirmed gas giant exoplanet orbiting the star WASP-133, located approximately 1823.5 light-years (559.08 parsecs) from the Solar System. First announced in 2016 by SuperWASP-South using the Transit detection technique (producing an estimated primary transit depth of 0.7456% across the stellar disk), this world measures 13.563 Earth radii (1.21 Jupiter radii) and has a measured mass of 368.683 Earth masses (1.16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.81 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2 g⊕ (19.61 m/s²), and an escape velocity of 58.3 km/s.
In its orbital architecture around WASP-133, WASP-133 b completes one full revolution every 2.176 Earth days at a semi-major axis of 0.0345 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 172.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.17 carries the world between 0.0286 AU at periapsis and 0.0404 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1790 K (+1517°C / +2763°F) and receiving 2,054.80 S⊕ (~2,796,577 W/m²), WASP-133 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-133 is classified as a solar-type yellow star of spectral type G4 with an effective photospheric temperature of 5,700 K, a radius of 1.44 R☉, a mass of 1.16 M☉, an estimated bolometric luminosity of 1.964 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.8 Gyr and a metallicity of [Fe/H] = 0.29 dex (metal-rich relative to the Sun). From Earth, WASP-133 shines at apparent V-band magnitude 12.891 (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-133 |
| Spectral Type | G4 |
| Effective Temp (Teff) | 5,700 K |
| Stellar Radius | 1.4400 R☉ |
| Stellar Mass | 1.1600 M☉ |
| Bolometric Luminosity | 1.964 L☉ |
| Metallicity [Fe/H] | 0.290 dex |
| Stellar Age | 6.800 Gyr |
| Apparent Magnitude | V: 12.891 · G: 12.715 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.034500 AU |
| Orbital Period | 2.176 days |
| Mean Orbital Velocity | 172.5 km/s |
| Orbital Eccentricity (e) | 0.17000 |
| Orbital Inclination (i) | 87.0000° |
| Mean Bulk Density | 0.81 g/cm³ (58.3 km/s vesc) |
| Insolation Flux | 2054.7956 S⊕ (~2,796,577 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1823.500 LY (559.084 pc) |