Kepler-1421 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1421 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1421, located approximately 2555.1 light-years (783.4 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0036% across the stellar disk), this world measures 0.93 Earth radii and has a measured mass of 0.749 Earth masses. Combining its mass and radius yields a mean bulk density of 5.13 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.87 g⊕ (8.53 m/s²), and an escape velocity of 10 km/s.

In its orbital architecture around Kepler-1421, Kepler-1421 b completes one full revolution every 6.913 Earth days at a semi-major axis of 0.07576 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.2 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 1209 K (+936°C / +1717°F) and receiving 649.15 S⊕ (~883,495 W/m²), Kepler-1421 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1421 is classified as a stellar host with an effective photospheric temperature of 6,335 K, a radius of 1.42 R☉, a mass of 1.25 M☉, an estimated bolometric luminosity of 2.914 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.75 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-1421 shines at apparent V-band magnitude 12.868 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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