Kepler-1231 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1231 b is a confirmed super-earth exoplanet orbiting the star Kepler-1231, located approximately 3219.9 light-years (987.24 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0169% across the stellar disk), this world measures 1.42 Earth radii and has a measured mass of 2.6 Earth masses. Combining its mass and radius yields a mean bulk density of 5.01 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.29 g⊕ (12.65 m/s²), and an escape velocity of 15.1 km/s.

In its orbital architecture around Kepler-1231, Kepler-1231 b completes one full revolution every 10.417 Earth days at a semi-major axis of 0.0914 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 95.5 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 870 K (+597°C / +1107°F) and receiving 117.52 S⊕ (~159,938 W/m²), Kepler-1231 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1231 is classified as a stellar host with an effective photospheric temperature of 5,778 K, a radius of 1 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 1 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.17 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1231 shines at apparent V-band magnitude 14.808 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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