Kepler-702 b

Astrophysical Synthesis & Habitability Characterization

Kepler-702 b is a confirmed gas giant exoplanet orbiting the star Kepler-702, located approximately 3235.7 light-years (992.07 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.9556% across the stellar disk), this world measures 9.17 Earth radii (0.82 Jupiter radii) and has a measured mass of 61.8 Earth masses (0.19 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.44 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.73 g⊕ (7.16 m/s²), and an escape velocity of 29 km/s.

In its orbital architecture around Kepler-702, Kepler-702 b completes one full revolution every 10.526 Earth days at a semi-major axis of 0.088 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 90.9 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 713 K (+440°C / +824°F) and receiving 88.91 S⊕ (~121,001 W/m²), Kepler-702 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-702 is classified as a stellar host with an effective photospheric temperature of 5,419 K, a radius of 0.86 R☉, a mass of 0.9 M☉, an estimated bolometric luminosity of 0.572 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-702 shines at apparent V-band magnitude 15.437 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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