Kepler-1769 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1769 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1769, located approximately 1429.9 light-years (438.41 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0999% across the stellar disk), this world measures 4.465 Earth radii (0.4 Jupiter radii) and has a measured mass of 18.2 Earth masses. Combining its mass and radius yields a mean bulk density of 1.13 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.91 g⊕ (8.92 m/s²), and an escape velocity of 22.6 km/s.

In its orbital architecture around Kepler-1769, Kepler-1769 b completes one full revolution every 89.193 Earth days at a semi-major axis of 0.40598 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 49.5 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 483 K (+210°C / +410°F) and receiving 8.90 S⊕ (~12,113 W/m²), Kepler-1769 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1769 is classified as a stellar host with an effective photospheric temperature of 6,071 K, a radius of 1.295 R☉, a mass of 1.061 M☉, an estimated bolometric luminosity of 2.044 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.02 Gyr and a metallicity of [Fe/H] = -0.06 dex (near-solar heavy-element abundance). From Earth, Kepler-1769 shines at apparent V-band magnitude 12.487 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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