KELT-7 b
Astrophysical Synthesis & Habitability Characterization
KELT-7 b is a confirmed gas giant exoplanet orbiting the star KELT-7, located approximately 445.8 light-years (136.68 parsecs) from the Solar System. First announced in 2015 by KELT using the Transit detection technique (producing an estimated primary transit depth of 0.8252% across the stellar disk), this world measures 17.934 Earth radii (1.6 Jupiter radii) and has a measured mass of 441.784 Earth masses (1.39 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 1.37 g⊕ (13.44 m/s²), and an escape velocity of 55.5 km/s.
In its orbital architecture around KELT-7, KELT-7 b completes one full revolution every 2.735 Earth days at a semi-major axis of 0.04415 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 175.6 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 2048 K (+1775°C / +3227°F) and receiving 1,775.39 S⊕ (~2,416,306 W/m²), KELT-7 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star KELT-7 is classified as a warm F-type star of spectral type F with an effective photospheric temperature of 6,768 K, a radius of 1.81 R☉, a mass of 1.76 M☉, an estimated bolometric luminosity of 6.167 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.3 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, KELT-7 shines at apparent V-band magnitude 8.56 (accessible to binoculars and small amateur telescopes) 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: KELT · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | KELT-7 |
| Spectral Type | F |
| Effective Temp (Teff) | 6,768 K |
| Stellar Radius | 1.8100 R☉ |
| Stellar Mass | 1.7600 M☉ |
| Bolometric Luminosity | 6.167 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 1.300 Gyr |
| Apparent Magnitude | V: 8.560 · G: 8.452 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044150 AU |
| Orbital Period | 2.735 days |
| Mean Orbital Velocity | 175.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 83.7600° |
| Mean Bulk Density | 0.42 g/cm³ (55.5 km/s vesc) |
| Insolation Flux | 1775.3900 S⊕ (~2,416,306 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 445.800 LY (136.681 pc) |