HAT-P-6 b

Astrophysical Synthesis & Habitability Characterization

HAT-P-6 b is a confirmed gas giant exoplanet orbiting the star HAT-P-6, located approximately 898.1 light-years (275.36 parsecs) from the Solar System. First announced in 2007 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 0.8814% across the stellar disk), this world measures 16.589 Earth radii (1.48 Jupiter radii) and has a measured mass of 419.536 Earth masses (1.32 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.51 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.52 g⊕ (14.91 m/s²), and an escape velocity of 56.3 km/s.

In its orbital architecture around HAT-P-6, HAT-P-6 b completes one full revolution every 3.853 Earth days at a semi-major axis of 0.05239 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 147.9 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1675 K (+1402°C / +2556°F) and receiving 1,099.44 S⊕ (~1,496,338 W/m²), HAT-P-6 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star HAT-P-6 is classified as a stellar host with an effective photospheric temperature of 6,570 K, a radius of 1.62 R☉, a mass of 1.79 M☉, an estimated bolometric luminosity of 4.387 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.3 Gyr and a metallicity of [Fe/H] = -0.13 dex (metal-poor relative to the Sun). From Earth, HAT-P-6 shines at apparent V-band magnitude 10.469 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: HATNet · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).