HD 102329 b
Astrophysical Synthesis & Habitability Characterization
HD 102329 b is a confirmed gas giant exoplanet orbiting the star HD 102329, located approximately 708.1 light-years (217.11 parsecs) from the Solar System. First announced in 2011 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2593.493 Earth masses (8.16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 7.15 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 16.34 g⊕ (160.24 m/s²), and an escape velocity of 160.5 km/s.
In its orbital architecture around HD 102329, HD 102329 b completes one full revolution every 778.1 Earth days (2.13Julian years) at a semi-major axis of 1.81 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 25.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.21 carries the world between 1.4299 AU at periapsis and 2.1901 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 533 K (+260°C / +500°F) and receiving 5.98 S⊕ (~8,142 W/m²), HD 102329 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 102329 is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 4,745 K, a radius of 9.82 R☉, a mass of 3.21 M☉, an estimated bolometric luminosity of 43.859 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.6 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, HD 102329 shines at apparent V-band magnitude 7.88 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 102329 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 102329 b sharing its stellar neighborhood alongside HD 102329 c.
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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 102329 |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 4,745 K |
| Stellar Radius | 9.8200 R☉ |
| Stellar Mass | 3.2100 M☉ |
| Bolometric Luminosity | 43.859 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 1.600 Gyr |
| Apparent Magnitude | V: 7.880 · G: 7.582 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.810000 AU |
| Orbital Period | 778.1 days |
| Mean Orbital Velocity | 25.3 km/s |
| Orbital Eccentricity (e) | 0.21000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 7.15 g/cm³ (160.5 km/s vesc) |
| Insolation Flux | 5.9827 S⊕ (~8,142 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 708.100 LY (217.107 pc) |