WASP-45 b
Astrophysical Synthesis & Habitability Characterization
WASP-45 b is a confirmed gas giant exoplanet orbiting the star WASP-45, located approximately 688.8 light-years (211.2 parsecs) from the Solar System. First announced in 2011 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 1.2929% across the stellar disk), this world measures 10.604 Earth radii (0.95 Jupiter radii) and has a measured mass of 306.388 Earth masses (0.96 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.42 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.72 g⊕ (26.67 m/s²), and an escape velocity of 60.1 km/s.
In its orbital architecture around WASP-45, WASP-45 b completes one full revolution every 3.126 Earth days at a semi-major axis of 0.03963 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 137.9 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 1153 K (+880°C / +1616°F) and receiving 294.00 S⊕ (~400,134 W/m²), WASP-45 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-45 is classified as an orange K-type star of spectral type K2 V with an effective photospheric temperature of 5,150 K, a radius of 0.855 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.461 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.7 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, WASP-45 shines at apparent V-band magnitude 11.801 (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-45 |
| Spectral Type | K2 V |
| Effective Temp (Teff) | 5,150 K |
| Stellar Radius | 0.8550 R☉ |
| Stellar Mass | 0.8500 M☉ |
| Bolometric Luminosity | 0.461 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 12.700 Gyr |
| Apparent Magnitude | V: 11.801 · G: 12.049 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.039630 AU |
| Orbital Period | 3.126 days |
| Mean Orbital Velocity | 137.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.0200° |
| Mean Bulk Density | 1.42 g/cm³ (60.1 km/s vesc) |
| Insolation Flux | 294.0000 S⊕ (~400,134 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 688.800 LY (211.196 pc) |