HIP 109600 b
Astrophysical Synthesis & Habitability Characterization
HIP 109600 b is a confirmed gas giant exoplanet orbiting the star HIP 109600, located approximately 216.4 light-years (66.34 parsecs) from the Solar System. First announced in 2016 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 851.784 Earth masses (2.68 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.04 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 4.89 g⊕ (47.95 m/s²), and an escape velocity of 89.9 km/s.
In its orbital architecture around HIP 109600, HIP 109600 b completes one full revolution every 232.08 Earth days at a semi-major axis of 0.706 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 33.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.163 carries the world between 0.5909 AU at periapsis and 0.8211 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.200 R⊕, HIP 109600 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 HIP 109600 is classified as a solar-type yellow star of spectral type G5 with an effective photospheric temperature of 5,530 K, a radius of 0.972 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.793 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, HIP 109600 shines at apparent V-band magnitude 9.18 (accessible to binoculars and small amateur telescopes) in the Northern 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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HIP 109600 |
| Spectral Type | G5 |
| Effective Temp (Teff) | 5,530 K |
| Stellar Radius | 0.9720 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.793 L☉ |
| Metallicity [Fe/H] | -0.120 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.180 · G: 9.004 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.706000 AU |
| Orbital Period | 232.08 days |
| Mean Orbital Velocity | 33.1 km/s |
| Orbital Eccentricity (e) | 0.16300 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.04 g/cm³ (89.9 km/s vesc) |
| Insolation Flux | 1.6736 S⊕ (~2,278 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 216.400 LY (66.336 pc) |