WASP-2 b
Astrophysical Synthesis & Habitability Characterization
WASP-2 b is a confirmed gas giant exoplanet orbiting the star WASP-2, located approximately 499.8 light-years (153.24 parsecs) from the Solar System. First announced in 2007 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 1.6455% across the stellar disk), this world measures 12.117 Earth radii (1.08 Jupiter radii) and has a measured mass of 295.9 Earth masses (0.93 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.02 g⊕ (19.81 m/s²), and an escape velocity of 55.3 km/s.
In its orbital architecture around WASP-2, WASP-2 b completes one full revolution every 2.152 Earth days at a semi-major axis of 0.03144 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 158.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0054 (ranging from 0.0313 AU at periapsis to 0.0316 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1311 K (+1038°C / +1900°F) and receiving 492.00 S⊕ (~669,612 W/m²), WASP-2 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-2 is classified as an orange K-type star of spectral type K1 with an effective photospheric temperature of 5,180 K, a radius of 0.866 R☉, a mass of 0.895 M☉, an estimated bolometric luminosity of 0.484 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.2 Gyr and a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, WASP-2 shines at apparent V-band magnitude 11.728 (faint and requiring research-grade or CCD telescopic photometry) 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-2 |
| Spectral Type | K1 |
| Effective Temp (Teff) | 5,180 K |
| Stellar Radius | 0.8660 R☉ |
| Stellar Mass | 0.8950 M☉ |
| Bolometric Luminosity | 0.484 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | 8.200 Gyr |
| Apparent Magnitude | V: 11.728 · G: 11.564 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.031440 AU |
| Orbital Period | 2.152 days |
| Mean Orbital Velocity | 158.9 km/s |
| Orbital Eccentricity (e) | 0.00540 |
| Orbital Inclination (i) | 84.4900° |
| Mean Bulk Density | 0.92 g/cm³ (55.3 km/s vesc) |
| Insolation Flux | 492.0000 S⊕ (~669,612 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 499.800 LY (153.242 pc) |