Kepler-1766 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1766 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1766, located approximately 1634.8 light-years (501.23 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0402% across the stellar disk), this world measures 2.279 Earth radii and has a measured mass of 5.81 Earth masses. Combining its mass and radius yields a mean bulk density of 2.71 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 17.9 km/s.

In its orbital architecture around Kepler-1766, Kepler-1766 b completes one full revolution every 105.015 Earth days at a semi-major axis of 0.4161 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 43.1 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 406 K (+133°C / +271°F) and receiving 7.80 S⊕ (~10,616 W/m²), Kepler-1766 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1766 is classified as a stellar host with an effective photospheric temperature of 5,868 K, a radius of 1.042 R☉, a mass of 0.915 M☉, an estimated bolometric luminosity of 1.155 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.02 Gyr and a metallicity of [Fe/H] = -0.22 dex (metal-poor relative to the Sun). From Earth, Kepler-1766 shines at apparent V-band magnitude 12.96 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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