HD 17674 b
Astrophysical Synthesis & Habitability Characterization
HD 17674 b is a confirmed gas giant exoplanet orbiting the star HD 17674, located approximately 144.9 light-years (44.43 parsecs) from the Solar System. First announced in 2017 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 276.512 Earth masses (0.87 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.57 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.43 g⊕ (14.02 m/s²), and an escape velocity of 49.9 km/s.
In its orbital architecture around HD 17674, HD 17674 b completes one full revolution every 623.8 Earth days (1.71Julian years) at a semi-major axis of 1.42 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 24.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 1.2354 AU at periapsis and 1.6046 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.900 R⊕, HD 17674 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 17674 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,904 K, a radius of 1.18 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 1.518 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.4 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, HD 17674 shines at apparent V-band magnitude 7.535 (accessible to binoculars and small amateur telescopes) in the Northern 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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 17674 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,904 K |
| Stellar Radius | 1.1800 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 1.518 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | 8.400 Gyr |
| Apparent Magnitude | V: 7.535 · G: 7.401 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.420000 AU |
| Orbital Period | 623.8 days |
| Mean Orbital Velocity | 24.8 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.57 g/cm³ (49.9 km/s vesc) |
| Insolation Flux | 0.7946 S⊕ (~1,081 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 144.900 LY (44.426 pc) |