HD 183263 c
Astrophysical Synthesis & Habitability Characterization
HD 183263 c 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 2008 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 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 2958.982 Earth masses (9.31 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.35 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 18.94 g⊕ (185.74 m/s²), and an escape velocity of 172.1 km/s.
In its orbital architecture around HD 183263, HD 183263 c completes one full revolution every 4667.978 Earth days (12.78Julian years) at a semi-major axis of 5.585 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 13 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.051 carries the world between 5.3002 AU at periapsis and 5.8698 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 135 K (-138°C / -216°F) and an incident flux of 0.06 S⊕ (~78 W/m²), surface water and volatile species on HD 183263 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
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 c sharing its stellar neighborhood alongside HD 183263 b.
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) | 5.585000 AU |
| Orbital Period | 4667.978 days |
| Mean Orbital Velocity | 13 km/s |
| Orbital Eccentricity (e) | 0.05100 |
| Orbital Inclination (i) | 73.7180° |
| Mean Bulk Density | 8.35 g/cm³ (172.1 km/s vesc) |
| Insolation Flux | 0.0570 S⊕ (~78 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 176.800 LY (54.196 pc) |