HD 143811 AB b
Astrophysical Synthesis & Habitability Characterization
HD 143811 AB b is a confirmed gas giant exoplanet orbiting the star HD 143811 A, located approximately 445.6 light-years (136.61 parsecs) from the Solar System. First announced in 2025 by Paranal Observatory using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 15.693 Earth radii (1.4 Jupiter radii) and has a measured mass of 1938.753 Earth masses (6.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.77 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 7.87 g⊕ (77.18 m/s²), and an escape velocity of 124.3 km/s.
In its orbital architecture around HD 143811 A, HD 143811 AB b completes one full revolution every 117000 Earth days (320.33Julian years) at a semi-major axis of 63 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 5.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.19 carries the world between 51.03 AU at periapsis and 74.97 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1042 K (+769°C / +1416°F) and receiving 0.00 S⊕ (~1 W/m²), HD 143811 AB b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 143811 A is classified as a stellar host with an effective photospheric temperature of 6,791 K, a radius of 1.684 R☉, a mass of 1.32 M☉, an estimated bolometric luminosity of 5.411 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.018 Gyr. From Earth, HD 143811 A shines at apparent V-band magnitude 8.91 (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 | HD 143811 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,791 K |
| Stellar Radius | 1.6840 R☉ |
| Stellar Mass | 1.3200 M☉ |
| Bolometric Luminosity | 5.411 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 0.018 Gyr |
| Apparent Magnitude | V: 8.910 · G: 8.788 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 63.000000 AU |
| Orbital Period | 117000 days |
| Mean Orbital Velocity | 5.9 km/s |
| Orbital Eccentricity (e) | 0.19000 |
| Orbital Inclination (i) | 37.0000° |
| Mean Bulk Density | 2.77 g/cm³ (124.3 km/s vesc) |
| Insolation Flux | 0.0011 S⊕ (~1 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 445.600 LY (136.608 pc) |