WASP-38 b
Astrophysical Synthesis & Habitability Characterization
WASP-38 b is a confirmed gas giant exoplanet orbiting the star WASP-38, located approximately 444.4 light-years (136.24 parsecs) from the Solar System. First announced in 2010 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.6915% across the stellar disk), this world measures 13.787 Earth radii (1.23 Jupiter radii) and has a measured mass of 1093.335 Earth masses (3.44 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.3 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.75 g⊕ (56.39 m/s²), and an escape velocity of 99.6 km/s.
In its orbital architecture around WASP-38, WASP-38 b completes one full revolution every 6.872 Earth days at a semi-major axis of 0.07522 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.1 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.03 (ranging from 0.073 AU at periapsis to 0.0775 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1250 K (+977°C / +1791°F) and receiving 501.50 S⊕ (~682,543 W/m²), WASP-38 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-38 is classified as a warm F-type star of spectral type F8 V with an effective photospheric temperature of 6,180 K, a radius of 1.52 R☉, a mass of 1.76 M☉, an estimated bolometric luminosity of 3.024 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.29 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, WASP-38 shines at apparent V-band magnitude 9.391 (accessible to binoculars and small amateur telescopes) 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: SuperWASP · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-38 |
| Spectral Type | F8 V |
| Effective Temp (Teff) | 6,180 K |
| Stellar Radius | 1.5200 R☉ |
| Stellar Mass | 1.7600 M☉ |
| Bolometric Luminosity | 3.024 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 3.290 Gyr |
| Apparent Magnitude | V: 9.391 · G: 9.210 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.075220 AU |
| Orbital Period | 6.872 days |
| Mean Orbital Velocity | 119.1 km/s |
| Orbital Eccentricity (e) | 0.03000 |
| Orbital Inclination (i) | 89.5000° |
| Mean Bulk Density | 2.3 g/cm³ (99.6 km/s vesc) |
| Insolation Flux | 501.5014 S⊕ (~682,543 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 444.400 LY (136.240 pc) |