HD 222582 b
Astrophysical Synthesis & Habitability Characterization
HD 222582 b is a confirmed gas giant exoplanet orbiting the star HD 222582, located approximately 137.5 light-years (42.16 parsecs) from the Solar System. First announced in 1999 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 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2660.237 Earth masses (8.37 Jupiter masses). Combining its mass and radius yields a mean bulk density of 7.33 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 16.76 g⊕ (164.36 m/s²), and an escape velocity of 162.5 km/s.
In its orbital architecture around HD 222582, HD 222582 b completes one full revolution every 572.38 Earth days (1.57Julian years) at a semi-major axis of 1.34 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 25.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.73, swinging from 0.3618 AU at periapsis out to 2.3182 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.600 R⊕, HD 222582 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 222582 is classified as a solar-type yellow star of spectral type G5 V with an effective photospheric temperature of 5,790 K, a radius of 1.13 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.288 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.24 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, HD 222582 shines at apparent V-band magnitude 7.68 (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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 222582 |
| Spectral Type | G5 V |
| Effective Temp (Teff) | 5,790 K |
| Stellar Radius | 1.1300 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.288 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 10.240 Gyr |
| Apparent Magnitude | V: 7.680 · G: 7.519 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.340000 AU |
| Orbital Period | 572.38 days |
| Mean Orbital Velocity | 25.5 km/s |
| Orbital Eccentricity (e) | 0.73000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 7.33 g/cm³ (162.5 km/s vesc) |
| Insolation Flux | 0.7253 S⊕ (~987 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 137.500 LY (42.159 pc) |