Kepler-774 b

Astrophysical Synthesis & Habitability Characterization

Kepler-774 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-774, located approximately 2993.5 light-years (917.8 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0144% across the stellar disk), this world measures 3.17 Earth radii (0.28 Jupiter radii) and has a measured mass of 10.2 Earth masses. Combining its mass and radius yields a mean bulk density of 1.77 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 20.1 km/s.

In its orbital architecture around Kepler-774, Kepler-774 b completes one full revolution every 11.09 Earth days at a semi-major axis of 0.1082 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 106.1 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 1422 K (+1149°C / +2100°F) and receiving 451.18 S⊕ (~614,052 W/m²), Kepler-774 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-774 is classified as a stellar host with an effective photospheric temperature of 6,403 K, a radius of 2.42 R☉, a mass of 1.57 M☉, an estimated bolometric luminosity of 8.832 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.14 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-774 shines at apparent V-band magnitude 12.886 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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