HD 170469 b
Astrophysical Synthesis & Habitability Characterization
HD 170469 b is a confirmed gas giant exoplanet orbiting the star HD 170469, located approximately 196.3 light-years (60.18 parsecs) from the Solar System. First announced in 2007 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 14.1 Earth radii (1.26 Jupiter radii) and has a measured mass of 209.768 Earth masses (0.66 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.41 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 43.1 km/s.
In its orbital architecture around HD 170469, HD 170469 b completes one full revolution every 1145 Earth days (3.13Julian years) at a semi-major axis of 2.24 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 21.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.11 carries the world between 1.9936 AU at periapsis and 2.4864 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 14.100 R⊕, HD 170469 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 170469 is classified as a solar-type yellow star of spectral type G5 IV with an effective photospheric temperature of 5,842 K, a radius of 1.24 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.607 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.7 Gyr and a metallicity of [Fe/H] = 0.29 dex (metal-rich relative to the Sun). From Earth, HD 170469 shines at apparent V-band magnitude 8.21 (accessible to binoculars and small amateur telescopes) in the Northern 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 170469 |
| Spectral Type | G5 IV |
| Effective Temp (Teff) | 5,842 K |
| Stellar Radius | 1.2400 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 1.607 L☉ |
| Metallicity [Fe/H] | 0.290 dex |
| Stellar Age | 6.700 Gyr |
| Apparent Magnitude | V: 8.210 · G: 8.050 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.240000 AU |
| Orbital Period | 1145 days |
| Mean Orbital Velocity | 21.3 km/s |
| Orbital Eccentricity (e) | 0.11000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.41 g/cm³ (43.1 km/s vesc) |
| Insolation Flux | 0.3188 S⊕ (~434 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 196.300 LY (60.178 pc) |