HD 148164 b
Astrophysical Synthesis & Habitability Characterization
HD 148164 b is a confirmed gas giant exoplanet orbiting the star HD 148164, located approximately 251.8 light-years (77.2 parsecs) from the Solar System. First announced in 2018 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 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 390.931 Earth masses (1.23 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.84 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.08 g⊕ (20.4 m/s²), and an escape velocity of 59.8 km/s.
In its orbital architecture around HD 148164, HD 148164 b completes one full revolution every 328.55 Earth days at a semi-major axis of 0.993 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 32.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.587, swinging from 0.4101 AU at periapsis out to 1.5759 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.700 R⊕, HD 148164 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HD 148164 is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,032 K, a radius of 1.34 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 2.133 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.41 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, HD 148164 shines at apparent V-band magnitude 8.23 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 148164 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 148164 b sharing its stellar neighborhood alongside HD 148164 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 148164 |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,032 K |
| Stellar Radius | 1.3400 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 2.133 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 2.410 Gyr |
| Apparent Magnitude | V: 8.230 · G: 8.091 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.993000 AU |
| Orbital Period | 328.55 days |
| Mean Orbital Velocity | 32.9 km/s |
| Orbital Eccentricity (e) | 0.58700 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.84 g/cm³ (59.8 km/s vesc) |
| Insolation Flux | 2.1682 S⊕ (~2,951 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 251.800 LY (77.197 pc) |