HATS-72 b
Astrophysical Synthesis & Habitability Characterization
HATS-72 b is a confirmed gas giant exoplanet orbiting the star HATS-72, located approximately 416.1 light-years (127.59 parsecs) from the Solar System. First announced in 2020 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 1.0589% across the stellar disk), this world measures 8.097 Earth radii (0.72 Jupiter radii) and has a measured mass of 39.856 Earth masses (0.13 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.41 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.61 g⊕ (5.98 m/s²), and an escape velocity of 24.8 km/s.
In its orbital architecture around HATS-72, HATS-72 b completes one full revolution every 7.328 Earth days at a semi-major axis of 0.066517 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 98.8 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.013 (ranging from 0.0657 AU at periapsis to 0.0674 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 739 K (+466°C / +871°F) and receiving 49.58 S⊕ (~67,478 W/m²), HATS-72 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-72 is classified as a stellar host with an effective photospheric temperature of 4,656 K, a radius of 0.7214 R☉, a mass of 0.7311 M☉, an estimated bolometric luminosity of 0.219 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.17 Gyr and a metallicity of [Fe/H] = 0.099 dex (metal-rich relative to the Sun). From Earth, HATS-72 shines at apparent V-band magnitude 12.324 (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-72 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,656 K |
| Stellar Radius | 0.7214 R☉ |
| Stellar Mass | 0.7311 M☉ |
| Bolometric Luminosity | 0.219 L☉ |
| Metallicity [Fe/H] | 0.099 dex |
| Stellar Age | 12.170 Gyr |
| Apparent Magnitude | V: 12.324 · G: 12.073 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.066517 AU |
| Orbital Period | 7.328 days |
| Mean Orbital Velocity | 98.8 km/s |
| Orbital Eccentricity (e) | 0.01300 |
| Orbital Inclination (i) | 89.5600° |
| Mean Bulk Density | 0.41 g/cm³ (24.8 km/s vesc) |
| Insolation Flux | 49.5800 S⊕ (~67,478 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 416.100 LY (127.589 pc) |