Kepler-67 b

Astrophysical Synthesis & Habitability Characterization

Kepler-67 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-67, located approximately 3689.4 light-years (1131.19 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.12% across the stellar disk), this world measures 2.94 Earth radii and has a measured mass of 8.96 Earth masses. Combining its mass and radius yields a mean bulk density of 1.94 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.5 km/s.

In its orbital architecture around Kepler-67, Kepler-67 b completes one full revolution every 15.726 Earth days at a semi-major axis of 0.1171 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 81 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 602 K (+329°C / +624°F) and receiving 30.60 S⊕ (~41,647 W/m²), Kepler-67 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-67 is classified as a solar-type yellow star of spectral type G9 V with an effective photospheric temperature of 5,331 K, a radius of 0.778 R☉, a mass of 0.865 M☉, an estimated bolometric luminosity of 0.439 L☉. Stellar evolution modeling indicates an estimated stellar age of 1 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, Kepler-67 shines at apparent V-band magnitude 16.172 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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