Kepler-1797 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1797 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1797, located approximately 4365.6 light-years (1338.49 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0772% across the stellar disk), this world measures 3.058 Earth radii (0.27 Jupiter radii) and has a measured mass of 9.58 Earth masses. Combining its mass and radius yields a mean bulk density of 1.85 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 19.8 km/s.

In its orbital architecture around Kepler-1797, Kepler-1797 b completes one full revolution every 23.359 Earth days at a semi-major axis of 0.1637 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 76.2 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 684 K (+411°C / +772°F) and receiving 51.68 S⊕ (~70,336 W/m²), Kepler-1797 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1797 is classified as a stellar host with an effective photospheric temperature of 6,244 K, a radius of 1.009 R☉, a mass of 1.069 M☉, an estimated bolometric luminosity of 1.388 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.4 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, Kepler-1797 shines at apparent V-band magnitude 15.421 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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