Kepler-667 b

Astrophysical Synthesis & Habitability Characterization

Kepler-667 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-667, located approximately 7509.6 light-years (2302.45 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.2484% across the stellar disk), this world measures 4.73 Earth radii (0.42 Jupiter radii) and has a measured mass of 20.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.05 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.9 g⊕ (8.83 m/s²), and an escape velocity of 23.1 km/s.

In its orbital architecture around Kepler-667, Kepler-667 b completes one full revolution every 41.44 Earth days at a semi-major axis of 0.2288 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.1 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 516 K (+243°C / +469°F) and receiving 71.82 S⊕ (~97,743 W/m²), Kepler-667 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-667 is classified as a stellar host with an effective photospheric temperature of 5,327 K, a radius of 0.87 R☉, a mass of 0.91 M☉, an estimated bolometric luminosity of 0.547 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.68 Gyr and a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, Kepler-667 shines at apparent V-band magnitude 15.362 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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