K2-130 b

Astrophysical Synthesis & Habitability Characterization

K2-130 b is a confirmed terrestrial exoplanet orbiting the star K2-130, located approximately 384.9 light-years (118.01 parsecs) from the Solar System. First announced in 2017 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0237% across the stellar disk), this world measures 1.25 Earth radii and has a measured mass of 2.1 Earth masses. Combining its mass and radius yields a mean bulk density of 5.93 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.34 g⊕ (13.14 m/s²), and an escape velocity of 14.5 km/s.

In its orbital architecture around K2-130, K2-130 b completes one full revolution every 2.494 Earth days at a semi-major axis of 0.032 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 139.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.17 carries the world between 0.0266 AU at periapsis and 0.0374 AU at apoapsis, driving measurable seasonal insolation cycles.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1013 K (+740°C / +1364°F) and receiving 136.40 S⊕ (~185,640 W/m²), K2-130 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star K2-130 is classified as a stellar host with an effective photospheric temperature of 4,356 K, a radius of 0.7443 R☉, a mass of 0.6956 M☉, an estimated bolometric luminosity of 0.179 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.24 dex (metal-poor relative to the Sun). From Earth, K2-130 shines at apparent V-band magnitude 12.676 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.

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