WASP-15 b

Astrophysical Synthesis & Habitability Characterization

WASP-15 b is a confirmed gas giant exoplanet orbiting the star WASP-15, located approximately 920.1 light-years (282.09 parsecs) from the Solar System. First announced in 2009 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.9585% across the stellar disk), this world measures 15.805 Earth radii (1.41 Jupiter radii) and has a measured mass of 171.628 Earth masses (0.54 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.24 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.69 g⊕ (6.77 m/s²), and an escape velocity of 36.9 km/s.

In its orbital architecture around WASP-15, WASP-15 b completes one full revolution every 3.752 Earth days at a semi-major axis of 0.05165 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 149.8 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 1676 K (+1403°C / +2557°F) and receiving 1,237.74 S⊕ (~1,684,560 W/m²), WASP-15 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star WASP-15 is classified as a warm F-type star of spectral type F7 with an effective photospheric temperature of 6,300 K, a radius of 1.48 R☉, a mass of 1.18 M☉, an estimated bolometric luminosity of 3.096 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.4 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, WASP-15 shines at apparent V-band magnitude 10.972 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.

Discovery Facility: SuperWASP · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).