Kepler-500 b

Astrophysical Synthesis & Habitability Characterization

Kepler-500 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-500, located approximately 2633.6 light-years (807.48 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0527% across the stellar disk), this world measures 2.58 Earth radii and has a measured mass of 7.18 Earth masses. Combining its mass and radius yields a mean bulk density of 2.31 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.7 km/s.

In its orbital architecture around Kepler-500, Kepler-500 b completes one full revolution every 8.508 Earth days at a semi-major axis of 0.08361 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 106.9 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 909 K (+636°C / +1177°F) and receiving 193.68 S⊕ (~263,598 W/m²), Kepler-500 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-500 is classified as a stellar host with an effective photospheric temperature of 5,813 K, a radius of 1.03 R☉, a mass of 1.02 M☉, an estimated bolometric luminosity of 1.087 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.37 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-500 shines at apparent V-band magnitude 14.324 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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