Kepler-851 b

Astrophysical Synthesis & Habitability Characterization

Kepler-851 b is a confirmed super-earth exoplanet orbiting the star Kepler-851, located approximately 2737.3 light-years (839.26 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0328% across the stellar disk), this world measures 1.68 Earth radii and has a measured mass of 3.46 Earth masses. Combining its mass and radius yields a mean bulk density of 4.02 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.23 g⊕ (12.06 m/s²), and an escape velocity of 16.1 km/s.

In its orbital architecture around Kepler-851, Kepler-851 b completes one full revolution every 8.507 Earth days at a semi-major axis of 0.0802 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.6 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 900 K (+627°C / +1161°F) and receiving 103.83 S⊕ (~141,310 W/m²), Kepler-851 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-851 is classified as a stellar host with an effective photospheric temperature of 5,455 K, a radius of 0.85 R☉, a mass of 0.89 M☉, an estimated bolometric luminosity of 0.574 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = -0.07 dex (near-solar heavy-element abundance). From Earth, Kepler-851 shines at apparent V-band magnitude 15.172 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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