HAT-P-63 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-63 b is a confirmed gas giant exoplanet orbiting the star HAT-P-63, located approximately 1315.9 light-years (403.46 parsecs) from the Solar System. First announced in 2021 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.4168% across the stellar disk), this world measures 12.543 Earth radii (1.12 Jupiter radii) and has a measured mass of 195.147 Earth masses (0.61 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.55 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.24 g⊕ (12.16 m/s²), and an escape velocity of 44.1 km/s.
In its orbital architecture around HAT-P-63, HAT-P-63 b completes one full revolution every 3.378 Earth days at a semi-major axis of 0.04294 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 138.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.069 carries the world between 0.04 AU at periapsis and 0.0459 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1237 K (+964°C / +1767°F) and receiving 387.40 S⊕ (~527,251 W/m²), HAT-P-63 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-63 is classified as a stellar host with an effective photospheric temperature of 5,400 K, a radius of 0.9661 R☉, a mass of 0.925 M☉, an estimated bolometric luminosity of 0.712 L☉. Stellar evolution modeling indicates an estimated stellar age of 9 Gyr and a metallicity of [Fe/H] = 0.251 dex (metal-rich relative to the Sun). From Earth, HAT-P-63 shines at apparent V-band magnitude 13.657 (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-63 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,400 K |
| Stellar Radius | 0.9661 R☉ |
| Stellar Mass | 0.9250 M☉ |
| Bolometric Luminosity | 0.712 L☉ |
| Metallicity [Fe/H] | 0.251 dex |
| Stellar Age | 9.000 Gyr |
| Apparent Magnitude | V: 13.657 · G: 13.511 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.042940 AU |
| Orbital Period | 3.378 days |
| Mean Orbital Velocity | 138.3 km/s |
| Orbital Eccentricity (e) | 0.06900 |
| Orbital Inclination (i) | 88.4500° |
| Mean Bulk Density | 0.55 g/cm³ (44.1 km/s vesc) |
| Insolation Flux | 387.4000 S⊕ (~527,251 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1315.900 LY (403.458 pc) |