HATS-76 b
Astrophysical Synthesis & Habitability Characterization
HATS-76 b is a confirmed gas giant exoplanet orbiting the star HATS-76, located approximately 1257.9 light-years (385.69 parsecs) from the Solar System. First announced in 2021 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 3.1381% across the stellar disk), this world measures 12.094 Earth radii (1.08 Jupiter radii) and has a measured mass of 835.571 Earth masses (2.63 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.6 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.71 g⊕ (56 m/s²), and an escape velocity of 93 km/s.
In its orbital architecture around HATS-76, HATS-76 b completes one full revolution every 1.942 Earth days at a semi-major axis of 0.02658 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 148.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.062 carries the world between 0.0249 AU at periapsis and 0.0282 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 940 K (+667°C / +1233°F) and receiving 129.80 S⊕ (~176,658 W/m²), HATS-76 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-76 is classified as a stellar host with an effective photospheric temperature of 4,016 K, a radius of 0.6259 R☉, a mass of 0.662 M☉, an estimated bolometric luminosity of 0.091 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.6 Gyr and a metallicity of [Fe/H] = 0.322 dex (metal-rich relative to the Sun). From Earth, HATS-76 shines at apparent V-band magnitude 16.68 (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-76 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,016 K |
| Stellar Radius | 0.6259 R☉ |
| Stellar Mass | 0.6620 M☉ |
| Bolometric Luminosity | 0.091 L☉ |
| Metallicity [Fe/H] | 0.322 dex |
| Stellar Age | 4.600 Gyr |
| Apparent Magnitude | V: 16.680 · G: 15.794 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.026580 AU |
| Orbital Period | 1.942 days |
| Mean Orbital Velocity | 148.9 km/s |
| Orbital Eccentricity (e) | 0.06200 |
| Orbital Inclination (i) | 88.2400° |
| Mean Bulk Density | 2.6 g/cm³ (93 km/s vesc) |
| Insolation Flux | 129.8000 S⊕ (~176,658 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1257.900 LY (385.689 pc) |