Kepler-80 g

Astrophysical Synthesis & Habitability Characterization

Kepler-80 g is a confirmed terrestrial exoplanet orbiting the star Kepler-80, located approximately 1205 light-years (369.45 parsecs) from the Solar System. First announced in 2017 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0233% across the stellar disk), this world measures 1.13 Earth radii and has a measured mass of 0.065 Earth masses. Combining its mass and radius yields a mean bulk density of 0.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.05 g⊕ (0.49 m/s²), and an escape velocity of 2.7 km/s.

In its orbital architecture around Kepler-80, Kepler-80 g completes one full revolution every 14.646 Earth days. Its moderate orbital eccentricity of e = 0.1303 driving measurable seasonal insolation cycles.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 418 K (+145°C / +293°F), Kepler-80 g orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-80 is classified as an orange K-type star of spectral type K5 with an effective photospheric temperature of 4,540 K, a radius of 0.678 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.175 L☉. Stellar evolution modeling indicates an estimated stellar age of 2 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-80 shines at apparent V-band magnitude 15.23 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-80 system is a multi-planet architecture hosting 6 confirmed worlds, with Kepler-80 g sharing its stellar neighborhood alongside Kepler-80 f, Kepler-80 d, Kepler-80 e, Kepler-80 b, Kepler-80 c.

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