HAT-P-43 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-43 b is a confirmed gas giant exoplanet orbiting the star HAT-P-43, located approximately 1724.8 light-years (528.83 parsecs) from the Solar System. First announced in 2012 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.3387% across the stellar disk), this world measures 13.63 Earth radii (1.22 Jupiter radii) and has a measured mass of 210.395 Earth masses (0.66 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.46 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.13 g⊕ (11.08 m/s²), and an escape velocity of 43.9 km/s.
In its orbital architecture around HAT-P-43, HAT-P-43 b completes one full revolution every 3.333 Earth days at a semi-major axis of 0.0444 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 144.9 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 1353 K (+1080°C / +1976°F) and receiving 521.88 S⊕ (~710,275 W/m²), HAT-P-43 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-43 is classified as a warm F-type star of spectral type F9 with an effective photospheric temperature of 5,693 K, a radius of 1.08 R☉, a mass of 1.03 M☉, an estimated bolometric luminosity of 1.099 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.7 Gyr and a metallicity of [Fe/H] = 0.2 dex (metal-rich relative to the Sun). From Earth, HAT-P-43 shines at apparent V-band magnitude 13.279 (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-43 |
| Spectral Type | F9 |
| Effective Temp (Teff) | 5,693 K |
| Stellar Radius | 1.0800 R☉ |
| Stellar Mass | 1.0300 M☉ |
| Bolometric Luminosity | 1.099 L☉ |
| Metallicity [Fe/H] | 0.200 dex |
| Stellar Age | 5.700 Gyr |
| Apparent Magnitude | V: 13.279 · G: 13.217 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044400 AU |
| Orbital Period | 3.333 days |
| Mean Orbital Velocity | 144.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.7000° |
| Mean Bulk Density | 0.46 g/cm³ (43.9 km/s vesc) |
| Insolation Flux | 521.8770 S⊕ (~710,275 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1724.800 LY (528.825 pc) |