WASP-155 b
Astrophysical Synthesis & Habitability Characterization
WASP-155 b is a confirmed gas giant exoplanet orbiting the star WASP-155, located approximately 1303.4 light-years (399.63 parsecs) from the Solar System. First announced in 2025 by SuperWASP using the Transit detection technique (producing an estimated primary transit depth of 0.989% across the stellar disk), this world measures 13.451 Earth radii (1.2 Jupiter radii) and has a measured mass of 276.829 Earth masses (0.87 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.63 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.53 g⊕ (15 m/s²), and an escape velocity of 50.7 km/s.
In its orbital architecture around WASP-155, WASP-155 b completes one full revolution every 3.11 Earth days at a semi-major axis of 0.043 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 150.4 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 1468 K (+1195°C / +2183°F) and receiving 771.00 S⊕ (~1,049,331 W/m²), WASP-155 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star WASP-155 is classified as a stellar host with an effective photospheric temperature of 5,660 K, a radius of 1.24 R☉, a mass of 1.09 M☉, an estimated bolometric luminosity of 1.416 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.7 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, WASP-155 shines at apparent V-band magnitude 12.365 (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: SuperWASP · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | WASP-155 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,660 K |
| Stellar Radius | 1.2400 R☉ |
| Stellar Mass | 1.0900 M☉ |
| Bolometric Luminosity | 1.416 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 1.700 Gyr |
| Apparent Magnitude | V: 12.365 · G: 12.496 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.043000 AU |
| Orbital Period | 3.11 days |
| Mean Orbital Velocity | 150.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7000° |
| Mean Bulk Density | 0.63 g/cm³ (50.7 km/s vesc) |
| Insolation Flux | 771.0000 S⊕ (~1,049,331 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1303.400 LY (399.630 pc) |