HAT-P-7 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-7 b is a confirmed gas giant exoplanet orbiting the star HAT-P-7, located approximately 1112.4 light-years (341.08 parsecs) from the Solar System. First announced in 2008 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 0.602% across the stellar disk), this world measures 16.926 Earth radii (1.51 Jupiter radii) and has a measured mass of 584.807 Earth masses (1.84 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.66 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.04 g⊕ (20.01 m/s²), and an escape velocity of 65.8 km/s.
In its orbital architecture around HAT-P-7, HAT-P-7 b completes one full revolution every 2.205 Earth days at a semi-major axis of 0.03809 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 188 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 2733 K (+2460°C / +4460°F) and receiving 4,353.41 S⊕ (~5,924,988 W/m²), HAT-P-7 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-7 is classified as a warm F-type star of spectral type F6 V with an effective photospheric temperature of 6,389 K, a radius of 2 R☉, a mass of 1.56 M☉, an estimated bolometric luminosity of 5.98 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.78 Gyr and a metallicity of [Fe/H] = 0.26 dex (metal-rich relative to the Sun). From Earth, HAT-P-7 shines at apparent V-band magnitude 10.481 (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-7 |
| Spectral Type | F6 V |
| Effective Temp (Teff) | 6,389 K |
| Stellar Radius | 2.0000 R☉ |
| Stellar Mass | 1.5600 M☉ |
| Bolometric Luminosity | 5.98 L☉ |
| Metallicity [Fe/H] | 0.260 dex |
| Stellar Age | 1.780 Gyr |
| Apparent Magnitude | V: 10.481 · G: 10.365 |
| System Architecture | 3 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.038090 AU |
| Orbital Period | 2.205 days |
| Mean Orbital Velocity | 188 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 83.1100° |
| Mean Bulk Density | 0.66 g/cm³ (65.8 km/s vesc) |
| Insolation Flux | 4353.4080 S⊕ (~5,924,988 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1112.400 LY (341.079 pc) |