Kepler-1811 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1811 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1811, located approximately 4535.4 light-years (1390.56 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0879% across the stellar disk), this world measures 3.848 Earth radii (0.34 Jupiter radii) and has a measured mass of 14.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.36 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 21.4 km/s.

In its orbital architecture around Kepler-1811, Kepler-1811 b completes one full revolution every 76.422 Earth days at a semi-major axis of 0.3462 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 49.3 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 455 K (+182°C / +360°F) and receiving 10.11 S⊕ (~13,760 W/m²), Kepler-1811 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1811 is classified as a stellar host with an effective photospheric temperature of 5,561 K, a radius of 1.19 R☉, a mass of 0.946 M☉, an estimated bolometric luminosity of 1.215 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.4 Gyr and a metallicity of [Fe/H] = 0.16 dex (metal-rich relative to the Sun). From Earth, Kepler-1811 shines at apparent V-band magnitude 15.327 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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