HD 156279 c
Astrophysical Synthesis & Habitability Characterization
HD 156279 c 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 2016 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 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 3098.827 Earth masses (9.75 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.75 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 19.83 g⊕ (194.47 m/s²), and an escape velocity of 176.1 km/s.
In its orbital architecture around HD 156279, HD 156279 c completes one full revolution every 4818.254 Earth days (13.19Julian years) at a semi-major axis of 5.486 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). The planet follows a highly eccentric trajectory (e = 0.261, swinging from 4.0542 AU at periapsis out to 6.9178 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 109 K (-164°C / -263°F) and an incident flux of 0.02 S⊕ (~32 W/m²), surface water and volatile species on HD 156279 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
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 c sharing its stellar neighborhood alongside HD 156279 b.
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 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) | 5.486000 AU |
| Orbital Period | 4818.254 days |
| Mean Orbital Velocity | 12.4 km/s |
| Orbital Eccentricity (e) | 0.26100 |
| Orbital Inclination (i) | 74.6990° |
| Mean Bulk Density | 8.75 g/cm³ (176.1 km/s vesc) |
| Insolation Flux | 0.0237 S⊕ (~32 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 118.100 LY (36.195 pc) |