K2-14 b

Astrophysical Synthesis & Habitability Characterization

K2-14 b is a confirmed sub-neptune exoplanet orbiting the star K2-14, located approximately 1187.4 light-years (364.05 parsecs) from the Solar System. First announced in 2015 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.9603% across the stellar disk), this world measures 4.81 Earth radii (0.43 Jupiter radii) and has a measured mass of 20.7 Earth masses. Combining its mass and radius yields a mean bulk density of 1.03 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.89 g⊕ (8.73 m/s²), and an escape velocity of 23.2 km/s.

In its orbital architecture around K2-14, K2-14 b completes one full revolution every 8.368 Earth days at a semi-major axis of 0.0627 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 81.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.14 carries the world between 0.0539 AU at periapsis and 0.0715 AU at apoapsis, driving measurable seasonal insolation cycles.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 488 K (+215°C / +419°F) and receiving 8.00 S⊕ (~10,888 W/m²), K2-14 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star K2-14 is classified as a low-mass red dwarf of spectral type M0 with an effective photospheric temperature of 3,789 K, a radius of 0.45 R☉, a mass of 0.47 M☉, an estimated bolometric luminosity of 0.037 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.37 dex (metal-poor relative to the Sun). From Earth, K2-14 shines at apparent V-band magnitude 15.78 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).