HATS-12 b
Astrophysical Synthesis & Habitability Characterization
HATS-12 b is a confirmed gas giant exoplanet orbiting the star HATS-12, located approximately 2433.6 light-years (746.14 parsecs) from the Solar System. First announced in 2016 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 0.3697% across the stellar disk), this world measures 7.76 Earth radii (0.69 Jupiter radii) and has a measured mass of 759.614 Earth masses (2.39 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.96 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 12.61 g⊕ (123.66 m/s²), and an escape velocity of 110.7 km/s.
In its orbital architecture around HATS-12, HATS-12 b completes one full revolution every 3.143 Earth days at a semi-major axis of 0.0441 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 152.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.085 carries the world between 0.0404 AU at periapsis and 0.0478 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1446 K (+1173°C / +2143°F) and receiving 566.48 S⊕ (~770,982 W/m²), HATS-12 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-12 is classified as a warm F-type star of spectral type F with an effective photospheric temperature of 6,357 K, a radius of 1.17 R☉, a mass of 1.16 M☉, an estimated bolometric luminosity of 2.006 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.36 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, HATS-12 shines at apparent V-band magnitude 12.831 (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-12 |
| Spectral Type | F |
| Effective Temp (Teff) | 6,357 K |
| Stellar Radius | 1.1700 R☉ |
| Stellar Mass | 1.1600 M☉ |
| Bolometric Luminosity | 2.006 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | 2.360 Gyr |
| Apparent Magnitude | V: 12.831 · G: 12.677 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044100 AU |
| Orbital Period | 3.143 days |
| Mean Orbital Velocity | 152.7 km/s |
| Orbital Eccentricity (e) | 0.08500 |
| Orbital Inclination (i) | 82.2700° |
| Mean Bulk Density | 8.96 g/cm³ (110.7 km/s vesc) |
| Insolation Flux | 566.4817 S⊕ (~770,982 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2433.600 LY (746.138 pc) |