Kepler-1919 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1919 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1919, located approximately 3840.6 light-years (1177.53 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0865% across the stellar disk), this world measures 2.624 Earth radii and has a measured mass of 7.38 Earth masses. Combining its mass and radius yields a mean bulk density of 2.25 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.8 km/s.

In its orbital architecture around Kepler-1919, Kepler-1919 b completes one full revolution every 37.887 Earth days at a semi-major axis of 0.2107 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.5 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 479 K (+206°C / +403°F) and receiving 12.46 S⊕ (~16,958 W/m²), Kepler-1919 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1919 is classified as a stellar host with an effective photospheric temperature of 5,513 K, a radius of 0.818 R☉, a mass of 0.868 M☉, an estimated bolometric luminosity of 0.555 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, Kepler-1919 shines at apparent V-band magnitude 16.161 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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