Kepler-801 b

Astrophysical Synthesis & Habitability Characterization

Kepler-801 b is a confirmed super-earth exoplanet orbiting the star Kepler-801, located approximately 1436.5 light-years (440.43 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0847% across the stellar disk), this world measures 2 Earth radii and has a measured mass of 4.66 Earth masses. Combining its mass and radius yields a mean bulk density of 3.21 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 17.1 km/s.

In its orbital architecture around Kepler-801, Kepler-801 b completes one full revolution every 11.419 Earth days at a semi-major axis of 0.0795 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 75.7 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 419 K (+146°C / +295°F) and receiving 14.44 S⊕ (~19,656 W/m²), Kepler-801 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-801 is classified as a stellar host with an effective photospheric temperature of 4,435 K, a radius of 0.63 R☉, a mass of 0.67 M☉, an estimated bolometric luminosity of 0.138 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, Kepler-801 shines at apparent V-band magnitude 15.596 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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