HIP 8923 b
Astrophysical Synthesis & Habitability Characterization
HIP 8923 b is a confirmed gas giant exoplanet orbiting the star HIP 8923, located approximately 215.2 light-years (66 parsecs) from the Solar System. First announced in 2026 by Multiple Facilities 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 3171.928 Earth masses (9.98 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.95 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 20.3 g⊕ (199.07 m/s²), and an escape velocity of 178.2 km/s.
In its orbital architecture around HIP 8923, HIP 8923 b completes one full revolution every 5160 Earth days (14.13Julian years) at a semi-major axis of 5.9 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 12.4 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.011 (ranging from 5.8351 AU at periapsis to 5.9649 AU at apoapsis), the planet experiences minimal orbital distance variation.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 136 K (-137°C / -215°F) and an incident flux of 0.05 S⊕ (~73 W/m²), surface water and volatile species on HIP 8923 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HIP 8923 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,980 K, a radius of 1.3216 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 2.004 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.73 Gyr and a metallicity of [Fe/H] = 0.42 dex (metal-rich relative to the Sun). From Earth, HIP 8923 shines at apparent V-band magnitude 8.24 (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 Facilities · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 8923 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,980 K |
| Stellar Radius | 1.3216 R☉ |
| Stellar Mass | 1.0100 M☉ |
| Bolometric Luminosity | 2.004 L☉ |
| Metallicity [Fe/H] | 0.420 dex |
| Stellar Age | 1.730 Gyr |
| Apparent Magnitude | V: 8.240 · G: 8.088 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.900000 AU |
| Orbital Period | 5160 days |
| Mean Orbital Velocity | 12.4 km/s |
| Orbital Eccentricity (e) | 0.01100 |
| Orbital Inclination (i) | 24.8000° |
| Mean Bulk Density | 8.95 g/cm³ (178.2 km/s vesc) |
| Insolation Flux | 0.0539 S⊕ (~73 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 215.200 LY (65.996 pc) |