Kepler-1775 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1775 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1775, located approximately 2142.9 light-years (657.02 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0412% across the stellar disk), this world measures 3.648 Earth radii (0.33 Jupiter radii) and has a measured mass of 12.9 Earth masses. Combining its mass and radius yields a mean bulk density of 1.47 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.97 g⊕ (9.51 m/s²), and an escape velocity of 21 km/s.

In its orbital architecture around Kepler-1775, Kepler-1775 b completes one full revolution every 85.654 Earth days at a semi-major axis of 0.39565 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 50.3 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 522 K (+249°C / +480°F) and receiving 9.90 S⊕ (~13,474 W/m²), Kepler-1775 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1775 is classified as a stellar host with an effective photospheric temperature of 5,818 K, a radius of 1.647 R☉, a mass of 1.149 M☉, an estimated bolometric luminosity of 2.789 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.57 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, Kepler-1775 shines at apparent V-band magnitude 13.429 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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