HAT-P-64 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-64 b is a confirmed gas giant exoplanet orbiting the star HAT-P-64, located approximately 2126.2 light-years (651.9 parsecs) from the Solar System. First announced in 2021 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.0174% across the stellar disk), this world measures 19.089 Earth radii (1.7 Jupiter radii) and has a measured mass of 184.34 Earth masses (0.58 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.15 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.51 g⊕ (5 m/s²), and an escape velocity of 34.8 km/s.
In its orbital architecture around HAT-P-64, HAT-P-64 b completes one full revolution every 4.007 Earth days at a semi-major axis of 0.05387 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 146.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.101 carries the world between 0.0484 AU at periapsis and 0.0593 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1766 K (+1493°C / +2719°F) and receiving 1,611.00 S⊕ (~2,192,571 W/m²), HAT-P-64 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-64 is classified as a stellar host with an effective photospheric temperature of 6,457 K, a radius of 1.735 R☉, a mass of 1.298 M☉, an estimated bolometric luminosity of 4.695 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.88 Gyr and a metallicity of [Fe/H] = -0.113 dex (metal-poor relative to the Sun). From Earth, HAT-P-64 shines at apparent V-band magnitude 12.855 (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-64 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,457 K |
| Stellar Radius | 1.7350 R☉ |
| Stellar Mass | 1.2980 M☉ |
| Bolometric Luminosity | 4.695 L☉ |
| Metallicity [Fe/H] | -0.113 dex |
| Stellar Age | 2.880 Gyr |
| Apparent Magnitude | V: 12.855 · G: 12.622 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.053870 AU |
| Orbital Period | 4.007 days |
| Mean Orbital Velocity | 146.2 km/s |
| Orbital Eccentricity (e) | 0.10100 |
| Orbital Inclination (i) | 88.0100° |
| Mean Bulk Density | 0.15 g/cm³ (34.8 km/s vesc) |
| Insolation Flux | 1611.0000 S⊕ (~2,192,571 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2126.200 LY (651.897 pc) |