Kepler-1700 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1700 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1700, located approximately 2340.5 light-years (717.6 parsecs) from the Solar System. First announced in 2020 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0591% across the stellar disk), this world measures 2.901 Earth radii and has a measured mass of 8.76 Earth masses. Combining its mass and radius yields a mean bulk density of 1.98 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.4 km/s.

In its orbital architecture around Kepler-1700, Kepler-1700 b completes one full revolution every 234.239 Earth days at a semi-major axis of 0.76094 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 35.3 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.

☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.901 R⊕, Kepler-1700 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.

The host star Kepler-1700 is classified as a stellar host with an effective photospheric temperature of 6,031 K, a radius of 1.0937 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.42 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.75 Gyr and a metallicity of [Fe/H] = 0.07 dex (metal-rich relative to the Sun). From Earth, Kepler-1700 shines at apparent V-band magnitude 13.764 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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