Kepler-815 b

Astrophysical Synthesis & Habitability Characterization

Kepler-815 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-815, located approximately 4107.2 light-years (1259.28 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0121% across the stellar disk), this world measures 4.11 Earth radii (0.37 Jupiter radii) and has a measured mass of 15.8 Earth masses. Combining its mass and radius yields a mean bulk density of 1.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.94 g⊕ (9.22 m/s²), and an escape velocity of 21.9 km/s.

In its orbital architecture around Kepler-815, Kepler-815 b completes one full revolution every 8.575 Earth days at a semi-major axis of 0.09473 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 120.2 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 1374 K (+1101°C / +2014°F) and receiving 979.14 S⊕ (~1,332,604 W/m²), Kepler-815 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-815 is classified as a stellar host with an effective photospheric temperature of 5,028 K, a radius of 3.42 R☉, a mass of 1.25 M☉, an estimated bolometric luminosity of 6.707 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.9 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-815 shines at apparent V-band magnitude 13.438 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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