HATS-6 b
Astrophysical Synthesis & Habitability Characterization
HATS-6 b is a confirmed gas giant exoplanet orbiting the star HATS-6, located approximately 552.2 light-years (169.32 parsecs) from the Solar System. First announced in 2015 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 3.2376% across the stellar disk), this world measures 11.187 Earth radii (1 Jupiter radii) and has a measured mass of 101.388 Earth masses (0.32 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.4 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.81 g⊕ (7.94 m/s²), and an escape velocity of 33.7 km/s.
In its orbital architecture around HATS-6, HATS-6 b completes one full revolution every 3.325 Earth days at a semi-major axis of 0.03623 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 118.5 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 713 K (+440°C / +824°F) and receiving 47.33 S⊕ (~64,418 W/m²), HATS-6 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-6 is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,724 K, a radius of 0.57 R☉, a mass of 0.574 M☉, an estimated bolometric luminosity of 0.056 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.1 Gyr and a metallicity of [Fe/H] = 0.2 dex (metal-rich relative to the Sun). From Earth, HATS-6 shines at apparent V-band magnitude 15.044 (faint and requiring research-grade or CCD telescopic photometry) 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: HATSouth · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HATS-6 |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,724 K |
| Stellar Radius | 0.5700 R☉ |
| Stellar Mass | 0.5740 M☉ |
| Bolometric Luminosity | 0.056 L☉ |
| Metallicity [Fe/H] | 0.200 dex |
| Stellar Age | 8.100 Gyr |
| Apparent Magnitude | V: 15.044 · G: 14.360 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.036230 AU |
| Orbital Period | 3.325 days |
| Mean Orbital Velocity | 118.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.2100° |
| Mean Bulk Density | 0.4 g/cm³ (33.7 km/s vesc) |
| Insolation Flux | 47.3315 S⊕ (~64,418 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 552.200 LY (169.318 pc) |