HATS-11 b
Astrophysical Synthesis & Habitability Characterization
HATS-11 b is a confirmed gas giant exoplanet orbiting the star HATS-11, located approximately 3080.9 light-years (944.6 parsecs) from the Solar System. First announced in 2016 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 1.1521% across the stellar disk), this world measures 18.03 Earth radii (1.61 Jupiter radii) and has a measured mass of 263.799 Earth masses (0.83 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.25 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 42.8 km/s.
In its orbital architecture around HATS-11, HATS-11 b completes one full revolution every 3.619 Earth days at a semi-major axis of 0.0507 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 152.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.34, swinging from 0.0335 AU at periapsis out to 0.0679 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1596 K (+1323°C / +2413°F) and receiving 1,027.30 S⊕ (~1,398,150 W/m²), HATS-11 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-11 is classified as a solar-type yellow star of spectral type G0 with an effective photospheric temperature of 6,563 K, a radius of 1.54 R☉, a mass of 1.33 M☉, an estimated bolometric luminosity of 3.948 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.7 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, HATS-11 shines at apparent V-band magnitude 14.06 (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-11 |
| Spectral Type | G0 |
| Effective Temp (Teff) | 6,563 K |
| Stellar Radius | 1.5400 R☉ |
| Stellar Mass | 1.3300 M☉ |
| Bolometric Luminosity | 3.948 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 7.700 Gyr |
| Apparent Magnitude | V: 14.060 · G: 13.833 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.050700 AU |
| Orbital Period | 3.619 days |
| Mean Orbital Velocity | 152.4 km/s |
| Orbital Eccentricity (e) | 0.34000 |
| Orbital Inclination (i) | 89.0300° |
| Mean Bulk Density | 0.25 g/cm³ (42.8 km/s vesc) |
| Insolation Flux | 1027.2960 S⊕ (~1,398,150 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3080.900 LY (944.603 pc) |