HD 156279 b
Astrophysical Synthesis & Habitability Characterization
HD 156279 b is a confirmed gas giant exoplanet orbiting the star HD 156279, located approximately 118.1 light-years (36.2 parsecs) from the Solar System. First announced in 2011 by Haute-Provence Observatory 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 2997.758 Earth masses (9.43 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.46 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 19.19 g⊕ (188.19 m/s²), and an escape velocity of 173.2 km/s.
In its orbital architecture around HD 156279, HD 156279 b completes one full revolution every 133.404 Earth days at a semi-major axis of 0.502 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 40.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.647, swinging from 0.1772 AU at periapsis out to 0.8268 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 362 K (+89°C / +192°F) and receiving 2.84 S⊕ (~3,859 W/m²), HD 156279 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 156279 is classified as a solar-type yellow star of spectral type G6 with an effective photospheric temperature of 5,453 K, a radius of 0.95 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.716 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.1 Gyr and a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, HD 156279 shines at apparent V-band magnitude 8.07 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 156279 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 156279 b sharing its stellar neighborhood alongside HD 156279 c.
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 | HD 156279 |
| Spectral Type | G6 |
| Effective Temp (Teff) | 5,453 K |
| Stellar Radius | 0.9500 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.716 L☉ |
| Metallicity [Fe/H] | 0.140 dex |
| Stellar Age | 4.100 Gyr |
| Apparent Magnitude | V: 8.070 · G: 7.866 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.502000 AU |
| Orbital Period | 133.404 days |
| Mean Orbital Velocity | 40.9 km/s |
| Orbital Eccentricity (e) | 0.64700 |
| Orbital Inclination (i) | 87.0000° |
| Mean Bulk Density | 8.46 g/cm³ (173.2 km/s vesc) |
| Insolation Flux | 2.8355 S⊕ (~3,859 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 118.100 LY (36.195 pc) |