HD 167768 b
Astrophysical Synthesis & Habitability Characterization
HD 167768 b is a confirmed gas giant exoplanet orbiting the star HD 167768, located approximately 349.7 light-years (107.21 parsecs) from the Solar System. First announced in 2022 by Okayama Astrophysical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 270.154 Earth masses (0.85 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.55 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.4 g⊕ (13.73 m/s²), and an escape velocity of 49.3 km/s.
In its orbital architecture around HD 167768, HD 167768 b completes one full revolution every 20.653 Earth days at a semi-major axis of 0.1512 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 79.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.149 carries the world between 0.1287 AU at periapsis and 0.1737 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1874 K (+1601°C / +2914°F) and receiving 2,042.74 S⊕ (~2,780,171 W/m²), HD 167768 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 167768 is classified as a solar-type yellow star of spectral type G8 III with an effective photospheric temperature of 4,851 K, a radius of 9.7 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 46.748 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.31 Gyr and a metallicity of [Fe/H] = -0.67 dex (metal-poor relative to the Sun). From Earth, HD 167768 shines at apparent V-band magnitude 5.989 (visible to the unaided human eye under dark skies) 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: Okayama Astrophysical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 167768 |
| Spectral Type | G8 III |
| Effective Temp (Teff) | 4,851 K |
| Stellar Radius | 9.7000 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 46.748 L☉ |
| Metallicity [Fe/H] | -0.670 dex |
| Stellar Age | 5.310 Gyr |
| Apparent Magnitude | V: 5.989 · G: 5.755 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.151200 AU |
| Orbital Period | 20.653 days |
| Mean Orbital Velocity | 79.6 km/s |
| Orbital Eccentricity (e) | 0.14900 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.55 g/cm³ (49.3 km/s vesc) |
| Insolation Flux | 2042.7410 S⊕ (~2,780,171 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 349.700 LY (107.214 pc) |