Kepler-99 b

Astrophysical Synthesis & Habitability Characterization

Kepler-99 b is a confirmed super-earth exoplanet orbiting the star Kepler-99, located approximately 679.6 light-years (208.37 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0345% across the stellar disk), this world measures 1.48 Earth radii and has a measured mass of 6.15 Earth masses. Combining its mass and radius yields a mean bulk density of 10.46 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 2.81 g⊕ (27.56 m/s²), and an escape velocity of 22.8 km/s.

In its orbital architecture around Kepler-99, Kepler-99 b completes one full revolution every 4.604 Earth days at a semi-major axis of 0.05071 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.8 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 810 K (+537°C / +999°F) and receiving 108.04 S⊕ (~147,045 W/m²), Kepler-99 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-99 is classified as a stellar host with an effective photospheric temperature of 4,782 K, a radius of 0.73 R☉, a mass of 0.79 M☉, an estimated bolometric luminosity of 0.25 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.47 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, Kepler-99 shines at apparent V-band magnitude 13.206 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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