Kepler-476 b

Astrophysical Synthesis & Habitability Characterization

Kepler-476 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-476, located approximately 2653.4 light-years (813.54 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0671% across the stellar disk), this world measures 3.08 Earth radii (0.27 Jupiter radii) and has a measured mass of 9.69 Earth masses. Combining its mass and radius yields a mean bulk density of 1.83 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 19.8 km/s.

In its orbital architecture around Kepler-476, Kepler-476 b completes one full revolution every 14.006 Earth days at a semi-major axis of 0.1126 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 87.5 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 807 K (+534°C / +993°F) and receiving 100.09 S⊕ (~136,222 W/m²), Kepler-476 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-476 is classified as a stellar host with an effective photospheric temperature of 5,837 K, a radius of 1.09 R☉, a mass of 1.03 M☉, an estimated bolometric luminosity of 1.237 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.37 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-476 shines at apparent V-band magnitude 14.018 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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