WASP-172 b
Astrophysical Synthesis & Habitability Characterization
WASP-172 b is a confirmed gas giant exoplanet orbiting the star WASP-172, located approximately 1755.1 light-years (538.11 parsecs) from the Solar System. First announced in 2018 by SuperWASP-South using the Transit detection technique (producing an estimated primary transit depth of 0.7135% across the stellar disk), this world measures 17.598 Earth radii (1.57 Jupiter radii) and has a measured mass of 149.38 Earth masses (0.47 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.15 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.48 g⊕ (4.71 m/s²), and an escape velocity of 32.6 km/s.
In its orbital architecture around WASP-172, WASP-172 b completes one full revolution every 5.477 Earth days at a semi-major axis of 0.0694 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 137.8 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 1740 K (+1467°C / +2673°F) and receiving 1,506.50 S⊕ (~2,050,347 W/m²), WASP-172 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-172 is classified as a warm F-type star of spectral type F1 V with an effective photospheric temperature of 6,900 K, a radius of 1.91 R☉, a mass of 1.49 M☉, an estimated bolometric luminosity of 7.419 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.79 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, WASP-172 shines at apparent V-band magnitude 10.988 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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: SuperWASP-South · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-172 |
| Spectral Type | F1 V |
| Effective Temp (Teff) | 6,900 K |
| Stellar Radius | 1.9100 R☉ |
| Stellar Mass | 1.4900 M☉ |
| Bolometric Luminosity | 7.419 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | 1.790 Gyr |
| Apparent Magnitude | V: 10.988 · G: 11.010 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.069400 AU |
| Orbital Period | 5.477 days |
| Mean Orbital Velocity | 137.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7000° |
| Mean Bulk Density | 0.15 g/cm³ (32.6 km/s vesc) |
| Insolation Flux | 1506.5000 S⊕ (~2,050,347 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1755.100 LY (538.110 pc) |