Kepler-522 b

Astrophysical Synthesis & Habitability Characterization

Kepler-522 b is a confirmed gas giant exoplanet orbiting the star Kepler-522, located approximately 2084.9 light-years (639.24 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1024% across the stellar disk), this world measures 6.91 Earth radii (0.62 Jupiter radii) and has a measured mass of 38.2 Earth masses (0.12 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.64 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.8 g⊕ (7.85 m/s²), and an escape velocity of 26.3 km/s.

In its orbital architecture around Kepler-522, Kepler-522 b completes one full revolution every 38.584 Earth days at a semi-major axis of 0.25029 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 70.6 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 761 K (+488°C / +910°F) and receiving 63.86 S⊕ (~86,907 W/m²), Kepler-522 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-522 is classified as a stellar host with an effective photospheric temperature of 6,392 K, a radius of 1.98 R☉, a mass of 1.54 M☉, an estimated bolometric luminosity of 5.872 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.7 Gyr and a metallicity of [Fe/H] = 0.41 dex (metal-rich relative to the Sun). From Earth, Kepler-522 shines at apparent V-band magnitude 12.22 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).