HAT-P-24 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-24 b is a confirmed gas giant exoplanet orbiting the star HAT-P-24, located approximately 1354.7 light-years (415.34 parsecs) from the Solar System. First announced in 2010 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 0.9372% across the stellar disk), this world measures 14.572 Earth radii (1.3 Jupiter radii) and has a measured mass of 238.373 Earth masses (0.75 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.42 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 45.2 km/s.
In its orbital architecture around HAT-P-24, HAT-P-24 b completes one full revolution every 3.355 Earth days at a semi-major axis of 0.04651 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 150.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 0.0433 AU at periapsis and 0.0498 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1637 K (+1364°C / +2487°F) and receiving 1,294.93 S⊕ (~1,762,398 W/m²), HAT-P-24 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-24 is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,373 K, a radius of 1.38 R☉, a mass of 1.37 M☉, an estimated bolometric luminosity of 2.819 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.8 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, HAT-P-24 shines at apparent V-band magnitude 11.762 (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-24 |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,373 K |
| Stellar Radius | 1.3800 R☉ |
| Stellar Mass | 1.3700 M☉ |
| Bolometric Luminosity | 2.819 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | 2.800 Gyr |
| Apparent Magnitude | V: 11.762 · G: 11.640 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.046510 AU |
| Orbital Period | 3.355 days |
| Mean Orbital Velocity | 150.8 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | 88.6000° |
| Mean Bulk Density | 0.42 g/cm³ (45.2 km/s vesc) |
| Insolation Flux | 1294.9290 S⊕ (~1,762,398 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1354.700 LY (415.344 pc) |