HD 107148 b
Astrophysical Synthesis & Habitability Characterization
HD 107148 b is a confirmed gas giant exoplanet orbiting the star HD 107148, located approximately 161.2 light-years (49.42 parsecs) from the Solar System. First announced in 2005 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 9.6 Earth radii (0.86 Jupiter radii) and has a measured mass of 66.741 Earth masses (0.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.42 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.72 g⊕ (7.06 m/s²), and an escape velocity of 29.5 km/s.
In its orbital architecture around HD 107148, HD 107148 b completes one full revolution every 48.056 Earth days at a semi-major axis of 0.269 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.05 carries the world between 0.2556 AU at periapsis and 0.2825 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 583 K (+310°C / +590°F) and receiving 18.25 S⊕ (~24,841 W/m²), HD 107148 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 107148 is classified as a solar-type yellow star of spectral type G5 V with an effective photospheric temperature of 5,797 K, a radius of 1.1692 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.385 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.6 Gyr and a metallicity of [Fe/H] = 0.314 dex (metal-rich relative to the Sun). From Earth, HD 107148 shines at apparent V-band magnitude 8.01 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 107148 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 107148 b sharing its stellar neighborhood alongside HD 107148 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 107148 |
| Spectral Type | G5 V |
| Effective Temp (Teff) | 5,797 K |
| Stellar Radius | 1.1692 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.385 L☉ |
| Metallicity [Fe/H] | 0.314 dex |
| Stellar Age | 5.600 Gyr |
| Apparent Magnitude | V: 8.010 · G: 7.851 |
| System Architecture | 2 Stars, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.269000 AU |
| Orbital Period | 48.056 days |
| Mean Orbital Velocity | 60.9 km/s |
| Orbital Eccentricity (e) | 0.05000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.42 g/cm³ (29.5 km/s vesc) |
| Insolation Flux | 18.2517 S⊕ (~24,841 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 161.200 LY (49.416 pc) |