HD 125612 b
Astrophysical Synthesis & Habitability Characterization
HD 125612 b is a confirmed gas giant exoplanet orbiting the star HD 125612, located approximately 187.9 light-years (57.62 parsecs) from the Solar System. First announced in 2007 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 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 945.222 Earth masses (2.97 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.27 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.42 g⊕ (53.15 m/s²), and an escape velocity of 94.7 km/s.
In its orbital architecture around HD 125612, HD 125612 b completes one full revolution every 557.7 Earth days (1.53Julian years) at a semi-major axis of 1.349 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 26.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.446, swinging from 0.7473 AU at periapsis out to 1.9507 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.200 R⊕, HD 125612 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 HD 125612 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,900 K, a radius of 1.07 R☉, a mass of 1.05 M☉, an estimated bolometric luminosity of 1.245 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.77 Gyr and a metallicity of [Fe/H] = 0.23 dex (metal-rich relative to the Sun). From Earth, HD 125612 shines at apparent V-band magnitude 8.31 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 125612 system is a multi-planet architecture hosting 3 confirmed worlds, with HD 125612 b sharing its stellar neighborhood alongside HD 125612 c, HD 125612 d.
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 125612 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,900 K |
| Stellar Radius | 1.0700 R☉ |
| Stellar Mass | 1.0500 M☉ |
| Bolometric Luminosity | 1.245 L☉ |
| Metallicity [Fe/H] | 0.230 dex |
| Stellar Age | 1.770 Gyr |
| Apparent Magnitude | V: 8.310 · G: 8.156 |
| System Architecture | 2 Stars, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.349000 AU |
| Orbital Period | 557.7 days |
| Mean Orbital Velocity | 26.3 km/s |
| Orbital Eccentricity (e) | 0.44600 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.27 g/cm³ (94.7 km/s vesc) |
| Insolation Flux | 0.6309 S⊕ (~859 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 187.900 LY (57.621 pc) |