HD 16905 b
Astrophysical Synthesis & Habitability Characterization
HD 16905 b is a confirmed gas giant exoplanet orbiting the star HD 16905, located approximately 129.6 light-years (39.74 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.4 Earth radii (1.11 Jupiter radii) and has a measured mass of 3591.461 Earth masses (11.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 10.39 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 23.36 g⊕ (229.08 m/s²), and an escape velocity of 190.4 km/s.
In its orbital architecture around HD 16905, HD 16905 b completes one full revolution every 10256 Earth days (28.08Julian years) at a semi-major axis of 8.8 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 9.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.68, swinging from 2.816 AU at periapsis out to 14.784 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 70 K (-203°C / -333°F) and an incident flux of 0.00 S⊕ (~5 W/m²), surface water and volatile species on HD 16905 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 16905 is classified as an orange K-type star of spectral type K3 V with an effective photospheric temperature of 4,866 K, a radius of 0.7749 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.302 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.1 Gyr and a metallicity of [Fe/H] = 0.241 dex (metal-rich relative to the Sun). From Earth, HD 16905 shines at apparent V-band magnitude 9.44 (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 16905 |
| Spectral Type | K3 V |
| Effective Temp (Teff) | 4,866 K |
| Stellar Radius | 0.7749 R☉ |
| Stellar Mass | 0.8500 M☉ |
| Bolometric Luminosity | 0.302 L☉ |
| Metallicity [Fe/H] | 0.241 dex |
| Stellar Age | 6.100 Gyr |
| Apparent Magnitude | V: 9.440 · G: 9.113 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 8.800000 AU |
| Orbital Period | 10256 days |
| Mean Orbital Velocity | 9.3 km/s |
| Orbital Eccentricity (e) | 0.68000 |
| Orbital Inclination (i) | 43.0000° |
| Mean Bulk Density | 10.39 g/cm³ (190.4 km/s vesc) |
| Insolation Flux | 0.0039 S⊕ (~5 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 129.600 LY (39.740 pc) |