HD 222076 b
Astrophysical Synthesis & Habitability Characterization
HD 222076 b is a confirmed gas giant exoplanet orbiting the star HD 222076, located approximately 297.3 light-years (91.15 parsecs) from the Solar System. First announced in 2016 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 495.815 Earth masses (1.56 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.11 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.72 g⊕ (26.67 m/s²), and an escape velocity of 67.8 km/s.
In its orbital architecture around HD 222076, HD 222076 b completes one full revolution every 871 Earth days (2.38Julian years) at a semi-major axis of 1.83 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 22.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.08 carries the world between 1.6836 AU at periapsis and 1.9764 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.500 R⊕, HD 222076 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 222076 is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 4,806 K, a radius of 4.1 R☉, a mass of 1.07 M☉, an estimated bolometric luminosity of 8.046 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.5 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, HD 222076 shines at apparent V-band magnitude 7.47 (accessible to binoculars and small amateur telescopes) 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 222076 |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 4,806 K |
| Stellar Radius | 4.1000 R☉ |
| Stellar Mass | 1.0700 M☉ |
| Bolometric Luminosity | 8.046 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 4.500 Gyr |
| Apparent Magnitude | V: 7.470 · G: 7.188 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.830000 AU |
| Orbital Period | 871 days |
| Mean Orbital Velocity | 22.9 km/s |
| Orbital Eccentricity (e) | 0.08000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.11 g/cm³ (67.8 km/s vesc) |
| Insolation Flux | 2.5381 S⊕ (~3,454 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 297.300 LY (91.154 pc) |