HD 192699 b
Astrophysical Synthesis & Habitability Characterization
HD 192699 b is a confirmed gas giant exoplanet orbiting the star HD 192699, located approximately 234.4 light-years (71.86 parsecs) from the Solar System. First announced in 2007 by Lick Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.4 Earth radii (1.2 Jupiter radii) and has a measured mass of 666.172 Earth masses (2.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.53 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.71 g⊕ (36.38 m/s²), and an escape velocity of 78.9 km/s.
In its orbital architecture around HD 192699, HD 192699 b completes one full revolution every 340.94 Earth days at a semi-major axis of 1.063 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 33.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.082 carries the world between 0.9758 AU at periapsis and 1.1502 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 495 K (+222°C / +432°F) and receiving 9.04 S⊕ (~12,297 W/m²), HD 192699 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 192699 is classified as a solar-type yellow star of spectral type G8 IV with an effective photospheric temperature of 5,041 K, a radius of 4.41 R☉, a mass of 1.38 M☉, an estimated bolometric luminosity of 11.268 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.8 Gyr and a metallicity of [Fe/H] = -0.15 dex (metal-poor relative to the Sun). From Earth, HD 192699 shines at apparent V-band magnitude 6.456 (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: Lick Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 192699 |
| Spectral Type | G8 IV |
| Effective Temp (Teff) | 5,041 K |
| Stellar Radius | 4.4100 R☉ |
| Stellar Mass | 1.3800 M☉ |
| Bolometric Luminosity | 11.268 L☉ |
| Metallicity [Fe/H] | -0.150 dex |
| Stellar Age | 1.800 Gyr |
| Apparent Magnitude | V: 6.456 · G: 6.211 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.063000 AU |
| Orbital Period | 340.94 days |
| Mean Orbital Velocity | 33.9 km/s |
| Orbital Eccentricity (e) | 0.08200 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.53 g/cm³ (78.9 km/s vesc) |
| Insolation Flux | 9.0351 S⊕ (~12,297 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 234.400 LY (71.863 pc) |