AF Lep b
Astrophysical Synthesis & Habitability Characterization
AF Lep b is a confirmed gas giant exoplanet orbiting the star AF Lep, located approximately 87.6 light-years (26.86 parsecs) from the Solar System. First announced in 2023 by Paranal Observatory using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 13 Earth radii (1.16 Jupiter radii) and has a measured mass of 1147.361 Earth masses (3.61 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.88 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.79 g⊕ (66.59 m/s²), and an escape velocity of 105.1 km/s.
In its orbital architecture around AF Lep, AF Lep b completes one full revolution every 8905 Earth days (24.38Julian years) at a semi-major axis of 8.996 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 11 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.015 (ranging from 8.8611 AU at periapsis to 9.1309 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1400 K (+1127°C / +2061°F) and receiving 0.02 S⊕ (~33 W/m²), AF Lep b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star AF Lep is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,140 K, a radius of 1.25 R☉, a mass of 1.218 M☉, an estimated bolometric luminosity of 1.992 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.024 Gyr and a metallicity of [Fe/H] = 0.19 dex (metal-rich relative to the Sun). From Earth, AF Lep shines at apparent V-band magnitude 6.332 (accessible to binoculars and small amateur telescopes) 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: Paranal Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | AF Lep |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,140 K |
| Stellar Radius | 1.2500 R☉ |
| Stellar Mass | 1.2180 M☉ |
| Bolometric Luminosity | 1.992 L☉ |
| Metallicity [Fe/H] | 0.190 dex |
| Stellar Age | 0.024 Gyr |
| Apparent Magnitude | V: 6.332 · G: 6.186 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 8.996000 AU |
| Orbital Period | 8905 days |
| Mean Orbital Velocity | 11 km/s |
| Orbital Eccentricity (e) | 0.01500 |
| Orbital Inclination (i) | 57.5000° |
| Mean Bulk Density | 2.88 g/cm³ (105.1 km/s vesc) |
| Insolation Flux | 0.0241 S⊕ (~33 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 87.600 LY (26.856 pc) |