HD 23127 b
Astrophysical Synthesis & Habitability Characterization
HD 23127 b is a confirmed gas giant exoplanet orbiting the star HD 23127, located approximately 306.1 light-years (93.86 parsecs) from the Solar System. First announced in 2006 by Anglo-Australian Telescope using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 485.326 Earth masses (1.53 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.09 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.66 g⊕ (26.09 m/s²), and an escape velocity of 67.1 km/s.
In its orbital architecture around HD 23127, HD 23127 b completes one full revolution every 1211.17 Earth days (3.32Julian years) at a semi-major axis of 2.37 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 21.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.406, swinging from 1.4078 AU at periapsis out to 3.3322 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.500 R⊕, HD 23127 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 23127 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,843 K, a radius of 1.49 R☉, a mass of 1.208 M☉, an estimated bolometric luminosity of 2.322 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.508 Gyr and a metallicity of [Fe/H] = 0.29 dex (metal-rich relative to the Sun). From Earth, HD 23127 shines at apparent V-band magnitude 8.58 (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: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 23127 |
| Spectral Type | G2 V |
| Effective Temp (Teff) | 5,843 K |
| Stellar Radius | 1.4900 R☉ |
| Stellar Mass | 1.2080 M☉ |
| Bolometric Luminosity | 2.322 L☉ |
| Metallicity [Fe/H] | 0.290 dex |
| Stellar Age | 4.508 Gyr |
| Apparent Magnitude | V: 8.580 · G: 8.420 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.370000 AU |
| Orbital Period | 1211.17 days |
| Mean Orbital Velocity | 21.3 km/s |
| Orbital Eccentricity (e) | 0.40600 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.09 g/cm³ (67.1 km/s vesc) |
| Insolation Flux | 0.5038 S⊕ (~686 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 306.100 LY (93.856 pc) |