Kepler-648 b

Astrophysical Synthesis & Habitability Characterization

Kepler-648 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-648, located approximately 2074.5 light-years (636.03 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0907% across the stellar disk), this world measures 3.22 Earth radii (0.29 Jupiter radii) and has a measured mass of 10.5 Earth masses. Combining its mass and radius yields a mean bulk density of 1.73 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.01 g⊕ (9.9 m/s²), and an escape velocity of 20.2 km/s.

In its orbital architecture around Kepler-648, Kepler-648 b completes one full revolution every 17.421 Earth days at a semi-major axis of 0.13324 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.2 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 674 K (+401°C / +754°F) and receiving 47.34 S⊕ (~64,424 W/m²), Kepler-648 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-648 is classified as a stellar host with an effective photospheric temperature of 5,741 K, a radius of 0.98 R☉, a mass of 1.05 M☉, an estimated bolometric luminosity of 0.936 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.82 Gyr and a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, Kepler-648 shines at apparent V-band magnitude 14.027 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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