Kepler-1806 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1806 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1806, located approximately 3190 light-years (978.07 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0751% across the stellar disk), this world measures 2.356 Earth radii and has a measured mass of 6.15 Earth masses. Combining its mass and radius yields a mean bulk density of 2.59 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 18.1 km/s.

In its orbital architecture around Kepler-1806, Kepler-1806 b completes one full revolution every 9.033 Earth days at a semi-major axis of 0.0813 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 97.9 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 729 K (+456°C / +853°F) and receiving 66.89 S⊕ (~91,037 W/m²), Kepler-1806 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1806 is classified as a stellar host with an effective photospheric temperature of 5,311 K, a radius of 0.788 R☉, a mass of 0.884 M☉, an estimated bolometric luminosity of 0.443 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.6 Gyr and a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1806 shines at apparent V-band magnitude 16.173 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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