K2-113 b

Astrophysical Synthesis & Habitability Characterization

K2-113 b is a confirmed gas giant exoplanet orbiting the star K2-113, located approximately 2073.4 light-years (635.72 parsecs) from the Solar System. First announced in 2017 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.8056% across the stellar disk), this world measures 12.14 Earth radii (1.08 Jupiter radii) and has a measured mass of 410.001 Earth masses (1.29 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.26 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.78 g⊕ (27.26 m/s²), and an escape velocity of 65 km/s.

In its orbital architecture around K2-113, K2-113 b completes one full revolution every 5.818 Earth days at a semi-major axis of 0.0642 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 120.1 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 1098 K (+825°C / +1517°F) and receiving 277.39 S⊕ (~377,528 W/m²), K2-113 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star K2-113 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,660 K, a radius of 1.24 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 1.416 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.9 Gyr and a metallicity of [Fe/H] = 0.27 dex (metal-rich relative to the Sun). From Earth, K2-113 shines at apparent V-band magnitude 13.744 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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