WASP-85 A b
Astrophysical Synthesis & Habitability Characterization
WASP-85 A b is a confirmed gas giant exoplanet orbiting the star WASP-85 A, located approximately 462.8 light-years (141.89 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 1.8573% across the stellar disk), this world measures 13.899 Earth radii (1.24 Jupiter radii) and has a measured mass of 402.055 Earth masses (1.27 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.83 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.08 g⊕ (20.4 m/s²), and an escape velocity of 60.2 km/s.
In its orbital architecture around WASP-85 A, WASP-85 A b completes one full revolution every 2.656 Earth days at a semi-major axis of 0.039 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 159.8 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 1452 K (+1179°C / +2154°F) and receiving 640.33 S⊕ (~871,483 W/m²), WASP-85 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-85 A is classified as a solar-type yellow star of spectral type G5 V with an effective photospheric temperature of 6,112 K, a radius of 0.935 R☉, a mass of 1.09 M☉, an estimated bolometric luminosity of 1.095 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.118 dex (metal-rich relative to the Sun). From Earth, WASP-85 A shines at apparent V-band magnitude 10.72 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-85 A |
| Spectral Type | G5 V |
| Effective Temp (Teff) | 6,112 K |
| Stellar Radius | 0.9350 R☉ |
| Stellar Mass | 1.0900 M☉ |
| Bolometric Luminosity | 1.095 L☉ |
| Metallicity [Fe/H] | 0.118 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 10.720 · G: 10.624 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.039000 AU |
| Orbital Period | 2.656 days |
| Mean Orbital Velocity | 159.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6900° |
| Mean Bulk Density | 0.83 g/cm³ (60.2 km/s vesc) |
| Insolation Flux | 640.3258 S⊕ (~871,483 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 462.800 LY (141.887 pc) |