HAT-P-52 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-52 b is a confirmed gas giant exoplanet orbiting the star HAT-P-52, located approximately 1177.9 light-years (361.16 parsecs) from the Solar System. First announced in 2015 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.3482% across the stellar disk), this world measures 11.31 Earth radii (1.01 Jupiter radii) and has a measured mass of 259.985 Earth masses (0.82 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.99 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.03 g⊕ (19.91 m/s²), and an escape velocity of 53.6 km/s.
In its orbital architecture around HAT-P-52, HAT-P-52 b completes one full revolution every 2.754 Earth days at a semi-major axis of 0.03694 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 145.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.047 (ranging from 0.0352 AU at periapsis to 0.0387 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1218 K (+945°C / +1733°F) and receiving 227.76 S⊕ (~309,980 W/m²), HAT-P-52 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-52 is classified as an orange K-type star of spectral type K1 with an effective photospheric temperature of 5,131 K, a radius of 0.893 R☉, a mass of 0.887 M☉, an estimated bolometric luminosity of 0.496 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.4 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, HAT-P-52 shines at apparent V-band magnitude 14.107 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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: HATNet · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HAT-P-52 |
| Spectral Type | K1 |
| Effective Temp (Teff) | 5,131 K |
| Stellar Radius | 0.8930 R☉ |
| Stellar Mass | 0.8870 M☉ |
| Bolometric Luminosity | 0.496 L☉ |
| Metallicity [Fe/H] | 0.280 dex |
| Stellar Age | 9.400 Gyr |
| Apparent Magnitude | V: 14.107 · G: 13.787 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.036940 AU |
| Orbital Period | 2.754 days |
| Mean Orbital Velocity | 145.9 km/s |
| Orbital Eccentricity (e) | 0.04700 |
| Orbital Inclination (i) | 87.0200° |
| Mean Bulk Density | 0.99 g/cm³ (53.6 km/s vesc) |
| Insolation Flux | 227.7590 S⊕ (~309,980 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1177.900 LY (361.155 pc) |