Kepler-1665 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1665 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1665, located approximately 1094.3 light-years (335.52 parsecs) from the Solar System. First announced in 2020 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.112% across the stellar disk), this world measures 2.839 Earth radii and has a measured mass of 8.44 Earth masses. Combining its mass and radius yields a mean bulk density of 2.03 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 19.3 km/s.

In its orbital architecture around Kepler-1665, Kepler-1665 b completes one full revolution every 11.955 Earth days at a semi-major axis of 0.096 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 87.4 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 906 K (+633°C / +1171°F) and receiving 40.40 S⊕ (~54,984 W/m²), Kepler-1665 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1665 is classified as a stellar host with an effective photospheric temperature of 5,050 K, a radius of 0.7778 R☉, a mass of 0.842 M☉, an estimated bolometric luminosity of 0.353 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.9 Gyr and a metallicity of [Fe/H] = -0.013 dex (near-solar heavy-element abundance). From Earth, Kepler-1665 shines at apparent V-band magnitude 13.737 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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