HD 8574 b
Astrophysical Synthesis & Habitability Characterization
HD 8574 b is a confirmed gas giant exoplanet orbiting the star HD 8574, located approximately 146.2 light-years (44.83 parsecs) from the Solar System. First announced in 2002 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.4 Earth radii (1.2 Jupiter radii) and has a measured mass of 645.195 Earth masses (2.03 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.48 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.59 g⊕ (35.21 m/s²), and an escape velocity of 77.6 km/s.
In its orbital architecture around HD 8574, HD 8574 b completes one full revolution every 227 Earth days at a semi-major axis of 0.76 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 36.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.3, swinging from 0.532 AU at periapsis out to 0.988 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 394 K (+121°C / +250°F) and receiving 4.12 S⊕ (~5,607 W/m²), HD 8574 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 8574 is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,064 K, a radius of 1.38 R☉, a mass of 1.34 M☉, an estimated bolometric luminosity of 2.31 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.6 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, HD 8574 shines at apparent V-band magnitude 7.12 (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 8574 |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,064 K |
| Stellar Radius | 1.3800 R☉ |
| Stellar Mass | 1.3400 M☉ |
| Bolometric Luminosity | 2.31 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 5.600 Gyr |
| Apparent Magnitude | V: 7.120 · G: 6.983 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.760000 AU |
| Orbital Period | 227 days |
| Mean Orbital Velocity | 36.4 km/s |
| Orbital Eccentricity (e) | 0.30000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.48 g/cm³ (77.6 km/s vesc) |
| Insolation Flux | 4.1197 S⊕ (~5,607 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 146.200 LY (44.826 pc) |