Kepler-1887 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1887 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1887, located approximately 4455.9 light-years (1366.18 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0963% across the stellar disk), this world measures 2.925 Earth radii and has a measured mass of 8.88 Earth masses. Combining its mass and radius yields a mean bulk density of 1.96 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.5 km/s.

In its orbital architecture around Kepler-1887, Kepler-1887 b completes one full revolution every 19.948 Earth days at a semi-major axis of 0.1421 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 77.5 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 625 K (+352°C / +666°F) and receiving 36.14 S⊕ (~49,187 W/m²), Kepler-1887 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1887 is classified as a stellar host with an effective photospheric temperature of 5,749 K, a radius of 0.864 R☉, a mass of 0.961 M☉, an estimated bolometric luminosity of 0.732 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.5 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, Kepler-1887 shines at apparent V-band magnitude 15.955 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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