HD 6434 b
Astrophysical Synthesis & Habitability Characterization
HD 6434 b is a confirmed gas giant exoplanet orbiting the star HD 6434, located approximately 138.2 light-years (42.36 parsecs) from the Solar System. First announced in 2003 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 14.2 Earth radii (1.27 Jupiter radii) and has a measured mass of 155.737 Earth masses (0.49 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.3 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.77 g⊕ (7.55 m/s²), and an escape velocity of 37 km/s.
In its orbital architecture around HD 6434, HD 6434 b completes one full revolution every 21.998 Earth days at a semi-major axis of 0.14 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 69.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.17 carries the world between 0.1162 AU at periapsis and 0.1638 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 787 K (+514°C / +957°F) and receiving 57.25 S⊕ (~77,912 W/m²), HD 6434 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 6434 is classified as a solar-type yellow star of spectral type G2/3 V with an effective photospheric temperature of 5,769 K, a radius of 1.12 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.247 L☉. Stellar evolution modeling indicates an estimated stellar age of 11.27 Gyr and a metallicity of [Fe/H] = -0.55 dex (metal-poor relative to the Sun). From Earth, HD 6434 shines at apparent V-band magnitude 7.72 (accessible to binoculars and small amateur telescopes) in the Southern 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 6434 |
| Spectral Type | G2/3 V |
| Effective Temp (Teff) | 5,769 K |
| Stellar Radius | 1.1200 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 1.247 L☉ |
| Metallicity [Fe/H] | -0.550 dex |
| Stellar Age | 11.270 Gyr |
| Apparent Magnitude | V: 7.720 · G: 7.561 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.140000 AU |
| Orbital Period | 21.998 days |
| Mean Orbital Velocity | 69.2 km/s |
| Orbital Eccentricity (e) | 0.17000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.3 g/cm³ (37 km/s vesc) |
| Insolation Flux | 57.2458 S⊕ (~77,912 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 138.200 LY (42.358 pc) |