Wolf 503 b
Astrophysical Synthesis & Habitability Characterization
Wolf 503 b is a confirmed sub-neptune exoplanet orbiting the star Wolf 503, located approximately 145.2 light-years (44.53 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0739% across the stellar disk), this world measures 2.043 Earth radii and has a measured mass of 6.26 Earth masses. Combining its mass and radius yields a mean bulk density of 4.05 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.5 g⊕ (14.71 m/s²), and an escape velocity of 19.6 km/s.
In its orbital architecture around Wolf 503, Wolf 503 b completes one full revolution every 6.001 Earth days at a semi-major axis of 0.05706 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 103.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.41, swinging from 0.0337 AU at periapsis out to 0.0805 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 790 K (+517°C / +963°F) and receiving 69.60 S⊕ (~94,726 W/m²), Wolf 503 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Wolf 503 is classified as an orange K-type star of spectral type K3.5 V with an effective photospheric temperature of 4,716 K, a radius of 0.689 R☉, a mass of 0.688 M☉, an estimated bolometric luminosity of 0.211 L☉. Stellar evolution modeling indicates an estimated stellar age of 11 Gyr and a metallicity of [Fe/H] = -0.47 dex (metal-poor relative to the Sun). From Earth, Wolf 503 shines at apparent V-band magnitude 10.27 (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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Wolf 503 |
| Spectral Type | K3.5 V |
| Effective Temp (Teff) | 4,716 K |
| Stellar Radius | 0.6890 R☉ |
| Stellar Mass | 0.6880 M☉ |
| Bolometric Luminosity | 0.211 L☉ |
| Metallicity [Fe/H] | -0.470 dex |
| Stellar Age | 11.000 Gyr |
| Apparent Magnitude | V: 10.270 · G: 9.898 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057060 AU |
| Orbital Period | 6.001 days |
| Mean Orbital Velocity | 103.4 km/s |
| Orbital Eccentricity (e) | 0.41000 |
| Orbital Inclination (i) | 89.8700° |
| Mean Bulk Density | 4.05 g/cm³ (19.6 km/s vesc) |
| Insolation Flux | 69.6000 S⊕ (~94,726 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 145.200 LY (44.526 pc) |