HD 169830 b
Astrophysical Synthesis & Habitability Characterization
HD 169830 b is a confirmed gas giant exoplanet orbiting the star HD 169830, located approximately 122.7 light-years (37.61 parsecs) from the Solar System. First announced in 2000 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 804.424 Earth masses (2.53 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.93 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.62 g⊕ (45.31 m/s²), and an escape velocity of 87.3 km/s.
In its orbital architecture around HD 169830, HD 169830 b completes one full revolution every 225.674 Earth days at a semi-major axis of 0.765 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 36.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.294, swinging from 0.5401 AU at periapsis out to 0.9899 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.200 R⊕, HD 169830 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HD 169830 is classified as a warm F-type star of spectral type F8 V with an effective photospheric temperature of 6,300 K, a radius of 1.9357 R☉, a mass of 1.17 M☉, an estimated bolometric luminosity of 5.296 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.2 Gyr and a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, HD 169830 shines at apparent V-band magnitude 5.9 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 169830 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 169830 b sharing its stellar neighborhood alongside HD 169830 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 169830 |
| Spectral Type | F8 V |
| Effective Temp (Teff) | 6,300 K |
| Stellar Radius | 1.9357 R☉ |
| Stellar Mass | 1.1700 M☉ |
| Bolometric Luminosity | 5.296 L☉ |
| Metallicity [Fe/H] | 0.210 dex |
| Stellar Age | 2.200 Gyr |
| Apparent Magnitude | V: 5.900 · G: 5.776 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.765000 AU |
| Orbital Period | 225.674 days |
| Mean Orbital Velocity | 36.9 km/s |
| Orbital Eccentricity (e) | 0.29400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.93 g/cm³ (87.3 km/s vesc) |
| Insolation Flux | 7.8465 S⊕ (~10,679 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 122.700 LY (37.605 pc) |