WASP-73 b

Astrophysical Synthesis & Habitability Characterization

WASP-73 b is a confirmed gas giant exoplanet orbiting the star WASP-73, located approximately 1032.9 light-years (316.68 parsecs) from the Solar System. First announced in 2014 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.3275% across the stellar disk), this world measures 15.917 Earth radii (1.42 Jupiter radii) and has a measured mass of 908.994 Earth masses (2.86 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.24 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.59 g⊕ (35.21 m/s²), and an escape velocity of 84.5 km/s.

In its orbital architecture around WASP-73, WASP-73 b completes one full revolution every 4.087 Earth days at a semi-major axis of 0.05512 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 146.7 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 1790 K (+1517°C / +2763°F) and receiving 2,242.36 S⊕ (~3,051,853 W/m²), WASP-73 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star WASP-73 is classified as a warm F-type star of spectral type F9 with an effective photospheric temperature of 6,030 K, a radius of 2.55 R☉, a mass of 2.52 M☉, an estimated bolometric luminosity of 7.713 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.3 Gyr and a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, WASP-73 shines at apparent V-band magnitude 10.468 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.

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