KELT-12 b

Astrophysical Synthesis & Habitability Characterization

KELT-12 b is a confirmed gas giant exoplanet orbiting the star KELT-12, located approximately 1200.4 light-years (368.03 parsecs) from the Solar System. First announced in 2017 by KELT-North using the Transit detection technique (producing an estimated primary transit depth of 0.5957% across the stellar disk), this world measures 19.952 Earth radii (1.78 Jupiter radii) and has a measured mass of 301.939 Earth masses (0.95 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.21 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.76 g⊕ (7.45 m/s²), and an escape velocity of 43.5 km/s.

In its orbital architecture around KELT-12, KELT-12 b completes one full revolution every 5.032 Earth days at a semi-major axis of 0.06708 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 145 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 1800 K (+1527°C / +2781°F) and receiving 1,749.00 S⊕ (~2,380,389 W/m²), KELT-12 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star KELT-12 is classified as a stellar host with an effective photospheric temperature of 6,279 K, a radius of 2.37 R☉, a mass of 1.591 M☉, an estimated bolometric luminosity of 7.833 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.2 Gyr and a metallicity of [Fe/H] = 0.19 dex (metal-rich relative to the Sun). From Earth, KELT-12 shines at apparent V-band magnitude 10.585 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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