Kepler-812 b

Astrophysical Synthesis & Habitability Characterization

Kepler-812 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-812, located approximately 4836 light-years (1482.74 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0362% across the stellar disk), this world measures 3.55 Earth radii (0.32 Jupiter radii) and has a measured mass of 12.3 Earth masses. Combining its mass and radius yields a mean bulk density of 1.52 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.98 g⊕ (9.61 m/s²), and an escape velocity of 20.8 km/s.

In its orbital architecture around Kepler-812, Kepler-812 b completes one full revolution every 10.117 Earth days at a semi-major axis of 0.1024 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 110.1 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 1163 K (+890°C / +1634°F) and receiving 421.92 S⊕ (~574,229 W/m²), Kepler-812 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-812 is classified as a stellar host with an effective photospheric temperature of 6,761 K, a radius of 1.71 R☉, a mass of 1.45 M☉, an estimated bolometric luminosity of 5.482 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.66 Gyr and a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-812 shines at apparent V-band magnitude 13.815 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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