Kepler-1251 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1251 b is a confirmed super-earth exoplanet orbiting the star Kepler-1251, located approximately 2942.6 light-years (902.2 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0359% across the stellar disk), this world measures 1.84 Earth radii and has a measured mass of 4.04 Earth masses. Combining its mass and radius yields a mean bulk density of 3.58 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.19 g⊕ (11.67 m/s²), and an escape velocity of 16.6 km/s.

In its orbital architecture around Kepler-1251, Kepler-1251 b completes one full revolution every 45.09 Earth days at a semi-major axis of 0.2478 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 59.8 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 487 K (+214°C / +417°F) and receiving 13.78 S⊕ (~18,755 W/m²), Kepler-1251 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1251 is classified as a stellar host with an effective photospheric temperature of 5,545 K, a radius of 0.89 R☉, a mass of 0.92 M☉, an estimated bolometric luminosity of 0.672 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.79 Gyr and a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1251 shines at apparent V-band magnitude 15.024 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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