KELT-6 c
Astrophysical Synthesis & Habitability Characterization
KELT-6 c is a confirmed gas giant exoplanet orbiting the star KELT-6, located approximately 785.1 light-years (240.73 parsecs) from the Solar System. First announced in 2015 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13 Earth radii (1.16 Jupiter radii) and has a measured mass of 1179.149 Earth masses (3.71 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.96 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.98 g⊕ (68.45 m/s²), and an escape velocity of 106.5 km/s.
In its orbital architecture around KELT-6, KELT-6 c completes one full revolution every 1276 Earth days (3.49Julian years) at a semi-major axis of 2.39 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 20.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.21 carries the world between 1.8881 AU at periapsis and 2.8919 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.000 R⊕, KELT-6 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star KELT-6 is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,272 K, a radius of 1.529 R☉, a mass of 1.126 M☉, an estimated bolometric luminosity of 3.246 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.9 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, KELT-6 shines at apparent V-band magnitude 10.371 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KELT-6 system is a multi-planet architecture hosting 2 confirmed worlds, with KELT-6 c sharing its stellar neighborhood alongside KELT-6 b.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | KELT-6 |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,272 K |
| Stellar Radius | 1.5290 R☉ |
| Stellar Mass | 1.1260 M☉ |
| Bolometric Luminosity | 3.246 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 4.900 Gyr |
| Apparent Magnitude | V: 10.371 · G: 10.193 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.390000 AU |
| Orbital Period | 1276 days |
| Mean Orbital Velocity | 20.4 km/s |
| Orbital Eccentricity (e) | 0.21000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.96 g/cm³ (106.5 km/s vesc) |
| Insolation Flux | 0.5448 S⊕ (~741 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 785.100 LY (240.726 pc) |