WASP-58 b

Astrophysical Synthesis & Habitability Characterization

WASP-58 b is a confirmed gas giant exoplanet orbiting the star WASP-58, located approximately 947.2 light-years (290.4 parsecs) from the Solar System. First announced in 2012 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 1.4509% across the stellar disk), this world measures 16.029 Earth radii (1.43 Jupiter radii) and has a measured mass of 308.295 Earth masses (0.97 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.41 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.2 g⊕ (11.77 m/s²), and an escape velocity of 49.1 km/s.

In its orbital architecture around WASP-58, WASP-58 b completes one full revolution every 5.017 Earth days at a semi-major axis of 0.0562 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 121.9 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 1270 K (+997°C / +1827°F) and receiving 404.71 S⊕ (~550,812 W/m²), WASP-58 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star WASP-58 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,800 K, a radius of 1.22 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.511 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.8 Gyr and a metallicity of [Fe/H] = -0.45 dex (metal-poor relative to the Sun). From Earth, WASP-58 shines at apparent V-band magnitude 11.652 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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