Kepler-890 b

Astrophysical Synthesis & Habitability Characterization

Kepler-890 b is a confirmed gas giant exoplanet orbiting the star Kepler-890, located approximately 5584.2 light-years (1712.12 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.5202% across the stellar disk), this world measures 8.89 Earth radii (0.79 Jupiter radii) and has a measured mass of 58.6 Earth masses (0.18 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.46 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.74 g⊕ (7.26 m/s²), and an escape velocity of 28.7 km/s.

In its orbital architecture around Kepler-890, Kepler-890 b completes one full revolution every 52.759 Earth days at a semi-major axis of 0.2944 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.7 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 540 K (+267°C / +513°F) and receiving 30.23 S⊕ (~41,139 W/m²), Kepler-890 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-890 is classified as a stellar host with an effective photospheric temperature of 5,954 K, a radius of 1.13 R☉, a mass of 1.09 M☉, an estimated bolometric luminosity of 1.44 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.63 Gyr and a metallicity of [Fe/H] = 0.09 dex (metal-rich relative to the Sun). From Earth, Kepler-890 shines at apparent V-band magnitude 15.235 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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