Kepler-881 b

Astrophysical Synthesis & Habitability Characterization

Kepler-881 b is a confirmed super-earth exoplanet orbiting the star Kepler-881, located approximately 4485.2 light-years (1375.18 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0224% across the stellar disk), this world measures 1.78 Earth radii and has a measured mass of 3.82 Earth masses. Combining its mass and radius yields a mean bulk density of 3.73 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.21 g⊕ (11.87 m/s²), and an escape velocity of 16.4 km/s.

In its orbital architecture around Kepler-881, Kepler-881 b completes one full revolution every 4.444 Earth days at a semi-major axis of 0.0552 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 135.1 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 1217 K (+944°C / +1731°F) and receiving 538.57 S⊕ (~732,992 W/m²), Kepler-881 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-881 is classified as a stellar host with an effective photospheric temperature of 5,961 K, a radius of 1.09 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.346 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.8 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-881 shines at apparent V-band magnitude 15.281 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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