HD 183263 b
Astrophysical Synthesis & Habitability Characterization
HD 183263 b is a confirmed gas giant exoplanet orbiting the star HD 183263, located approximately 176.8 light-years (54.2 parsecs) from the Solar System. First announced in 2004 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 13.1 Earth radii (1.17 Jupiter radii) and has a measured mass of 1103.182 Earth masses (3.47 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.71 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.43 g⊕ (63.06 m/s²), and an escape velocity of 102.7 km/s.
In its orbital architecture around HD 183263, HD 183263 b completes one full revolution every 624.874 Earth days (1.71Julian years) at a semi-major axis of 1.46 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 25.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.383, swinging from 0.9008 AU at periapsis out to 2.0192 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.100 R⊕, HD 183263 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 183263 is classified as a solar-type yellow star of spectral type G2 IV with an effective photospheric temperature of 5,948 K, a radius of 1.23 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.699 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.13 Gyr and a metallicity of [Fe/H] = 0.278 dex (metal-rich relative to the Sun). From Earth, HD 183263 shines at apparent V-band magnitude 7.86 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 183263 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 183263 b sharing its stellar neighborhood alongside HD 183263 c.
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 183263 |
| Spectral Type | G2 IV |
| Effective Temp (Teff) | 5,948 K |
| Stellar Radius | 1.2300 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 1.699 L☉ |
| Metallicity [Fe/H] | 0.278 dex |
| Stellar Age | 8.130 Gyr |
| Apparent Magnitude | V: 7.860 · G: 7.718 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.460000 AU |
| Orbital Period | 624.874 days |
| Mean Orbital Velocity | 25.4 km/s |
| Orbital Eccentricity (e) | 0.38300 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 2.71 g/cm³ (102.7 km/s vesc) |
| Insolation Flux | 0.8347 S⊕ (~1,136 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 176.800 LY (54.196 pc) |