WASP-181 b

Astrophysical Synthesis & Habitability Characterization

WASP-181 b is a confirmed gas giant exoplanet orbiting the star WASP-181, located approximately 1426.9 light-years (437.5 parsecs) from the Solar System. First announced in 2019 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 1.5896% across the stellar disk), this world measures 13.271 Earth radii (1.18 Jupiter radii) and has a measured mass of 95.031 Earth masses (0.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.54 g⊕ (5.3 m/s²), and an escape velocity of 29.9 km/s.

In its orbital architecture around WASP-181, WASP-181 b completes one full revolution every 4.52 Earth days at a semi-major axis of 0.05427 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 130.6 km/s (compared to Earth's 29.8 km/s).

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1186 K (+913°C / +1675°F) and receiving 382.45 S⊕ (~520,513 W/m²), WASP-181 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star WASP-181 is classified as a solar-type yellow star of spectral type G2 with an effective photospheric temperature of 5,839 K, a radius of 0.965 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 0.971 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.5 Gyr and a metallicity of [Fe/H] = 0.09 dex (metal-rich relative to the Sun). From Earth, WASP-181 shines at apparent V-band magnitude 12.924 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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