KELT-11 b

Astrophysical Synthesis & Habitability Characterization

KELT-11 b is a confirmed gas giant exoplanet orbiting the star KELT-11, located approximately 323.4 light-years (99.16 parsecs) from the Solar System. First announced in 2017 by KELT-South using the Transit detection technique (producing an estimated primary transit depth of 0.266% across the stellar disk), this world measures 15.132 Earth radii (1.35 Jupiter radii) and has a measured mass of 65.155 Earth masses (0.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.1 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.28 g⊕ (2.75 m/s²), and an escape velocity of 23.2 km/s.

In its orbital architecture around KELT-11, KELT-11 b completes one full revolution every 4.736 Earth days at a semi-major axis of 0.0623 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 143.1 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 1712 K (+1439°C / +2622°F) and receiving 1,433.00 S⊕ (~1,950,313 W/m²), KELT-11 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star KELT-11 is classified as a solar-type yellow star of spectral type G8/K0 IV with an effective photospheric temperature of 5,375 K, a radius of 2.69 R☉, a mass of 1.44 M☉, an estimated bolometric luminosity of 5.419 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.17 dex (metal-rich relative to the Sun). From Earth, KELT-11 shines at apparent V-band magnitude 8.04 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.

Discovery Facility: KELT-South · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).