Kepler-1902 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1902 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1902, located approximately 1123.1 light-years (344.34 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.044% across the stellar disk), this world measures 1.176 Earth radii and has a measured mass of 1.74 Earth masses. Combining its mass and radius yields a mean bulk density of 5.9 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.26 g⊕ (12.36 m/s²), and an escape velocity of 13.6 km/s.

In its orbital architecture around Kepler-1902, Kepler-1902 b completes one full revolution every 3.822 Earth days at a semi-major axis of 0.0385 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 109.6 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 601 K (+328°C / +622°F) and receiving 30.84 S⊕ (~41,973 W/m²), Kepler-1902 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1902 is classified as a stellar host with an effective photospheric temperature of 3,729 K, a radius of 0.514 R☉, a mass of 0.52 M☉, an estimated bolometric luminosity of 0.046 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1902 shines at apparent V-band magnitude 16.113 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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