HD 108147 b
Astrophysical Synthesis & Habitability Characterization
HD 108147 b is a confirmed gas giant exoplanet orbiting the star HD 108147, located approximately 126.9 light-years (38.92 parsecs) from the Solar System. First announced in 2002 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 10.9 Earth radii (0.97 Jupiter radii) and has a measured mass of 82.95 Earth masses (0.26 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.35 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.7 g⊕ (6.86 m/s²), and an escape velocity of 30.9 km/s.
In its orbital architecture around HD 108147, HD 108147 b completes one full revolution every 10.899 Earth days at a semi-major axis of 0.102 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 101.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.53, swinging from 0.0479 AU at periapsis out to 0.1561 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 890 K (+617°C / +1143°F) and receiving 193.09 S⊕ (~262,799 W/m²), HD 108147 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 108147 is classified as a warm F-type star of spectral type F8 V CH+0.4 with an effective photospheric temperature of 6,256 K, a radius of 1.2066 R☉, a mass of 1.22 M☉, an estimated bolometric luminosity of 2.001 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, HD 108147 shines at apparent V-band magnitude 6.99 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 108147 |
| Spectral Type | F8 V CH+0.4 |
| Effective Temp (Teff) | 6,256 K |
| Stellar Radius | 1.2066 R☉ |
| Stellar Mass | 1.2200 M☉ |
| Bolometric Luminosity | 2.001 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 6.990 · G: 6.853 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.102000 AU |
| Orbital Period | 10.899 days |
| Mean Orbital Velocity | 101.8 km/s |
| Orbital Eccentricity (e) | 0.53000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.35 g/cm³ (30.9 km/s vesc) |
| Insolation Flux | 193.0925 S⊕ (~262,799 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 126.900 LY (38.920 pc) |