Kepler-1890 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1890 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1890, located approximately 1727.3 light-years (529.6 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0033% across the stellar disk), this world measures 0.869 Earth radii and has a measured mass of 0.587 Earth masses. Combining its mass and radius yields a mean bulk density of 4.93 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.78 g⊕ (7.65 m/s²), and an escape velocity of 9.2 km/s.

In its orbital architecture around Kepler-1890, Kepler-1890 b completes one full revolution every 4.821 Earth days at a semi-major axis of 0.05712 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 128.9 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 1328 K (+1055°C / +1931°F) and receiving 493.00 S⊕ (~670,973 W/m²), Kepler-1890 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1890 is classified as a stellar host with an effective photospheric temperature of 6,046 K, a radius of 1.396 R☉, a mass of 1.024 M☉, an estimated bolometric luminosity of 2.336 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.65 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, Kepler-1890 shines at apparent V-band magnitude 12.916 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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