Kepler-491 b

Astrophysical Synthesis & Habitability Characterization

Kepler-491 b is a confirmed gas giant exoplanet orbiting the star Kepler-491, located approximately 2057.3 light-years (630.79 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.6304% across the stellar disk), this world measures 8.92 Earth radii (0.8 Jupiter radii) and has a measured mass of 59 Earth masses (0.19 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.46 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.74 g⊕ (7.26 m/s²), and an escape velocity of 28.8 km/s.

In its orbital architecture around Kepler-491, Kepler-491 b completes one full revolution every 4.225 Earth days at a semi-major axis of 0.05191 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 133.7 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 1111 K (+838°C / +1540°F) and receiving 312.51 S⊕ (~425,332 W/m²), Kepler-491 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-491 is classified as a stellar host with an effective photospheric temperature of 5,582 K, a radius of 1.03 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 0.924 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = 0.37 dex (metal-rich relative to the Sun). From Earth, Kepler-491 shines at apparent V-band magnitude 14.178 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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