HATS-56 b
Astrophysical Synthesis & Habitability Characterization
HATS-56 b is a confirmed gas giant exoplanet orbiting the star HATS-56, located approximately 1840.9 light-years (564.41 parsecs) from the Solar System. First announced in 2019 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 0.6211% across the stellar disk), this world measures 18.921 Earth radii (1.69 Jupiter radii) and has a measured mass of 191.334 Earth masses (0.6 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.16 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.53 g⊕ (5.2 m/s²), and an escape velocity of 35.6 km/s.
In its orbital architecture around HATS-56, HATS-56 b completes one full revolution every 4.325 Earth days at a semi-major axis of 0.06043 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 152 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.019 (ranging from 0.0593 AU at periapsis to 0.0616 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1902 K (+1629°C / +2964°F) and receiving 1,080.87 S⊕ (~1,471,064 W/m²), HATS-56 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-56 is classified as a stellar host with an effective photospheric temperature of 6,536 K, a radius of 2.201 R☉, a mass of 1.573 M☉, an estimated bolometric luminosity of 7.932 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.894 Gyr and a metallicity of [Fe/H] = 0.19 dex (metal-rich relative to the Sun). From Earth, HATS-56 shines at apparent V-band magnitude 11.477 (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-56 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,536 K |
| Stellar Radius | 2.2010 R☉ |
| Stellar Mass | 1.5730 M☉ |
| Bolometric Luminosity | 7.932 L☉ |
| Metallicity [Fe/H] | 0.190 dex |
| Stellar Age | 1.894 Gyr |
| Apparent Magnitude | V: 11.477 · G: 11.488 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.060430 AU |
| Orbital Period | 4.325 days |
| Mean Orbital Velocity | 152 km/s |
| Orbital Eccentricity (e) | 0.01900 |
| Orbital Inclination (i) | 83.2900° |
| Mean Bulk Density | 0.16 g/cm³ (35.6 km/s vesc) |
| Insolation Flux | 1080.8700 S⊕ (~1,471,064 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1840.900 LY (564.409 pc) |