Kepler-1212 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1212 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1212, located approximately 4294.1 light-years (1316.57 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0291% across the stellar disk), this world measures 2.14 Earth radii and has a measured mass of 5.22 Earth masses. Combining its mass and radius yields a mean bulk density of 2.94 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.14 g⊕ (11.18 m/s²), and an escape velocity of 17.5 km/s.

In its orbital architecture around Kepler-1212, Kepler-1212 b completes one full revolution every 12.941 Earth days at a semi-major axis of 0.1082 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 91 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 795 K (+522°C / +972°F) and receiving 142.10 S⊕ (~193,393 W/m²), Kepler-1212 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1212 is classified as a stellar host with an effective photospheric temperature of 6,051 K, a radius of 1.15 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.591 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.24 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-1212 shines at apparent V-band magnitude 15.133 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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