Kepler-826 b

Astrophysical Synthesis & Habitability Characterization

Kepler-826 b is a confirmed terrestrial exoplanet orbiting the star Kepler-826, located approximately 2542.7 light-years (779.6 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0099% across the stellar disk), this world measures 1.25 Earth radii and has a measured mass of 2.1 Earth masses. Combining its mass and radius yields a mean bulk density of 5.93 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.34 g⊕ (13.14 m/s²), and an escape velocity of 14.5 km/s.

In its orbital architecture around Kepler-826, Kepler-826 b completes one full revolution every 4.488 Earth days at a semi-major axis of 0.05202 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 126.1 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 1305 K (+1032°C / +1890°F) and receiving 827.22 S⊕ (~1,125,848 W/m²), Kepler-826 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-826 is classified as a stellar host with an effective photospheric temperature of 6,079 K, a radius of 1.15 R☉, a mass of 1.05 M☉, an estimated bolometric luminosity of 1.62 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.37 Gyr and a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, Kepler-826 shines at apparent V-band magnitude 13.644 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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