HD 107148 c
Astrophysical Synthesis & Habitability Characterization
HD 107148 c is a confirmed sub-neptune exoplanet orbiting the star HD 107148, located approximately 161.2 light-years (49.42 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.7 Earth radii (0.42 Jupiter radii) and has a measured mass of 19.896 Earth masses. Combining its mass and radius yields a mean bulk density of 1.06 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.9 g⊕ (8.83 m/s²), and an escape velocity of 23 km/s.
In its orbital architecture around HD 107148, HD 107148 c completes one full revolution every 18.327 Earth days at a semi-major axis of 0.1407 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.34, swinging from 0.0929 AU at periapsis out to 0.1885 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 800 K (+527°C / +981°F) and receiving 66.71 S⊕ (~90,798 W/m²), HD 107148 c 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 5,753 K, a radius of 1.1692 R☉, a mass of 1.1052 M☉, an estimated bolometric luminosity of 1.344 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.6 Gyr and a metallicity of [Fe/H] = 0.296 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 c sharing its stellar neighborhood alongside HD 107148 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 107148 |
| Spectral Type | G5 V |
| Effective Temp (Teff) | 5,753 K |
| Stellar Radius | 1.1692 R☉ |
| Stellar Mass | 1.1052 M☉ |
| Bolometric Luminosity | 1.344 L☉ |
| Metallicity [Fe/H] | 0.296 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) | 0.140700 AU |
| Orbital Period | 18.327 days |
| Mean Orbital Velocity | 83.5 km/s |
| Orbital Eccentricity (e) | 0.34000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.06 g/cm³ (23 km/s vesc) |
| Insolation Flux | 66.7145 S⊕ (~90,798 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 161.200 LY (49.416 pc) |