Kepler-959 b

Astrophysical Synthesis & Habitability Characterization

Kepler-959 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-959, located approximately 2634.5 light-years (807.73 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0399% across the stellar disk), this world measures 4.38 Earth radii (0.39 Jupiter radii) and has a measured mass of 17.6 Earth masses. Combining its mass and radius yields a mean bulk density of 1.15 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.92 g⊕ (9.02 m/s²), and an escape velocity of 22.4 km/s.

In its orbital architecture around Kepler-959, Kepler-959 b completes one full revolution every 14.801 Earth days at a semi-major axis of 0.1633 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 120 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 1912 K (+1639°C / +2982°F) and receiving 165.87 S⊕ (~225,746 W/m²), Kepler-959 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-959 is classified as a stellar host with an effective photospheric temperature of 7,005 K, a radius of 2.01 R☉, a mass of 1.6 M☉, an estimated bolometric luminosity of 8.728 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.35 Gyr and a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-959 shines at apparent V-band magnitude 12.606 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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