HD 185283 b
Astrophysical Synthesis & Habitability Characterization
HD 185283 b is a confirmed gas giant exoplanet orbiting the star HD 185283, located approximately 102.4 light-years (31.4 parsecs) from the Solar System. First announced in 2023 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.6 Earth radii (1.21 Jupiter radii) and has a measured mass of 413.177 Earth masses (1.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.91 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.23 g⊕ (21.87 m/s²), and an escape velocity of 61.7 km/s.
In its orbital architecture around HD 185283, HD 185283 b completes one full revolution every 4060 Earth days (11.12Julian years) at a semi-major axis of 4.6 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 12.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 4.278 AU at periapsis and 4.922 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 94 K (-179°C / -290°F) and an incident flux of 0.01 S⊕ (~18 W/m²), surface water and volatile species on HD 185283 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 185283 is classified as an orange K-type star of spectral type K3 V with an effective photospheric temperature of 4,848 K, a radius of 0.7433 R☉, a mass of 0.8 M☉, an estimated bolometric luminosity of 0.274 L☉. Stellar evolution modeling indicates an estimated stellar age of 6 Gyr and a metallicity of [Fe/H] = -0.06 dex (near-solar heavy-element abundance). From Earth, HD 185283 shines at apparent V-band magnitude 9.03 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 185283 |
| Spectral Type | K3 V |
| Effective Temp (Teff) | 4,848 K |
| Stellar Radius | 0.7433 R☉ |
| Stellar Mass | 0.8000 M☉ |
| Bolometric Luminosity | 0.274 L☉ |
| Metallicity [Fe/H] | -0.060 dex |
| Stellar Age | 6.000 Gyr |
| Apparent Magnitude | V: 9.030 · G: 8.713 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 4.600000 AU |
| Orbital Period | 4060 days |
| Mean Orbital Velocity | 12.3 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | 91.0000° |
| Mean Bulk Density | 0.91 g/cm³ (61.7 km/s vesc) |
| Insolation Flux | 0.0130 S⊕ (~18 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 102.400 LY (31.395 pc) |