Kepler-1696 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1696 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1696, located approximately 4913.1 light-years (1506.36 parsecs) from the Solar System. First announced in 2020 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0462% across the stellar disk), this world measures 2.81 Earth radii and has a measured mass of 8.29 Earth masses. Combining its mass and radius yields a mean bulk density of 2.06 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 19.2 km/s.

In its orbital architecture around Kepler-1696, Kepler-1696 b completes one full revolution every 65.941 Earth days at a semi-major axis of 0.3244 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 53.5 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 454 K (+181°C / +358°F) and receiving 10.04 S⊕ (~13,664 W/m²), Kepler-1696 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1696 is classified as a stellar host with an effective photospheric temperature of 5,712 K, a radius of 1.1981 R☉, a mass of 1.02 M☉, an estimated bolometric luminosity of 1.371 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1696 shines at apparent V-band magnitude 15.505 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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