Kepler-516 b

Astrophysical Synthesis & Habitability Characterization

Kepler-516 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-516, located approximately 2241 light-years (687.09 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0679% across the stellar disk), this world measures 5.74 Earth radii (0.51 Jupiter radii) and has a measured mass of 27.9 Earth masses. Combining its mass and radius yields a mean bulk density of 0.81 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.85 g⊕ (8.34 m/s²), and an escape velocity of 24.7 km/s.

In its orbital architecture around Kepler-516, Kepler-516 b completes one full revolution every 24.855 Earth days at a semi-major axis of 0.1992 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 87.2 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 1095 K (+822°C / +1512°F) and receiving 174.58 S⊕ (~237,603 W/m²), Kepler-516 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-516 is classified as a stellar host with an effective photospheric temperature of 7,099 K, a radius of 2.02 R☉, a mass of 1.62 M☉, an estimated bolometric luminosity of 9.298 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.32 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-516 shines at apparent V-band magnitude 12.121 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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