K2-131 b

Astrophysical Synthesis & Habitability Characterization

K2-131 b is a confirmed super-earth exoplanet orbiting the star K2-131, located approximately 497.4 light-years (152.51 parsecs) from the Solar System. First announced in 2017 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0416% across the stellar disk), this world measures 1.69 Earth radii and has a measured mass of 7.9 Earth masses. Combining its mass and radius yields a mean bulk density of 9.02 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 2.77 g⊕ (27.16 m/s²), and an escape velocity of 24.2 km/s.

In its orbital architecture around K2-131, K2-131 b completes one full revolution every 0.369 Earth days at a semi-major axis of 0.00936 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 275.7 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 2223 K (+1950°C / +3542°F) and receiving 4,070.00 S⊕ (~5,539,270 W/m²), K2-131 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star K2-131 is classified as a stellar host with an effective photospheric temperature of 5,120 K, a radius of 0.7595 R☉, a mass of 0.803 M☉, an estimated bolometric luminosity of 0.356 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.3 Gyr and a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, K2-131 shines at apparent V-band magnitude 12.129 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.

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