HD 130322 b
Astrophysical Synthesis & Habitability Characterization
HD 130322 b is a confirmed gas giant exoplanet orbiting the star HD 130322, located approximately 104 light-years (31.88 parsecs) from the Solar System. First announced in 1999 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 365.49 Earth masses (1.15 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.78 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.95 g⊕ (19.12 m/s²), and an escape velocity of 57.8 km/s.
In its orbital architecture around HD 130322, HD 130322 b completes one full revolution every 10.709 Earth days at a semi-major axis of 0.0925 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 94 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.029 (ranging from 0.0898 AU at periapsis to 0.0952 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 720 K (+447°C / +837°F) and receiving 67.96 S⊕ (~92,498 W/m²), HD 130322 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 130322 is classified as an orange K-type star of spectral type K0 V with an effective photospheric temperature of 5,387 K, a radius of 0.85 R☉, a mass of 0.92 M☉, an estimated bolometric luminosity of 0.546 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.35 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, HD 130322 shines at apparent V-band magnitude 8.04 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 130322 |
| Spectral Type | K0 V |
| Effective Temp (Teff) | 5,387 K |
| Stellar Radius | 0.8500 R☉ |
| Stellar Mass | 0.9200 M☉ |
| Bolometric Luminosity | 0.546 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 0.350 Gyr |
| Apparent Magnitude | V: 8.040 · G: 7.834 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.092500 AU |
| Orbital Period | 10.709 days |
| Mean Orbital Velocity | 94 km/s |
| Orbital Eccentricity (e) | 0.02900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.78 g/cm³ (57.8 km/s vesc) |
| Insolation Flux | 67.9633 S⊕ (~92,498 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 104.000 LY (31.877 pc) |