K2-95 b

Astrophysical Synthesis & Habitability Characterization

K2-95 b is a confirmed sub-neptune exoplanet orbiting the star K2-95, located approximately 586.6 light-years (179.85 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.5755% across the stellar disk), this world measures 3.31 Earth radii (0.3 Jupiter radii) and has a measured mass of 11 Earth masses. Combining its mass and radius yields a mean bulk density of 1.67 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1 g⊕ (9.81 m/s²), and an escape velocity of 20.4 km/s.

In its orbital architecture around K2-95, K2-95 b completes one full revolution every 10.135 Earth days at a semi-major axis of 0.0525 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 56.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.16 carries the world between 0.0441 AU at periapsis and 0.0609 AU at apoapsis, driving measurable seasonal insolation cycles.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 474 K (+201°C / +394°F) and receiving 8.42 S⊕ (~11,456 W/m²), K2-95 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star K2-95 is classified as a low-mass red dwarf of spectral type M3.0 with an effective photospheric temperature of 3,566 K, a radius of 0.4 R☉, a mass of 0.41 M☉, an estimated bolometric luminosity of 0.023 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.79 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, K2-95 shines at apparent V-band magnitude 17.236 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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