Kepler-297 d

Astrophysical Synthesis & Habitability Characterization

Kepler-297 d is a confirmed gas giant exoplanet orbiting the star Kepler-297, located approximately 2257.5 light-years (692.14 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 11.1018% across the stellar disk), this world has a measured radius of 32.6 Earth radii (2.91 R♃), though radial-velocity mass constraints remain unmeasured in the current composite catalogue.

In its orbital architecture around Kepler-297, Kepler-297 d completes one full revolution every 150.019 Earth days at a semi-major axis of 0.523 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 37.9 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.

☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 32.600 R⊕, Kepler-297 d 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-297 is classified as a stellar host with an effective photospheric temperature of 5,618 K, a radius of 0.897 R☉, a mass of 0.846 M☉, an estimated bolometric luminosity of 0.719 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.9 Gyr and a metallicity of [Fe/H] = -0.22 dex (metal-poor relative to the Sun). From Earth, Kepler-297 shines at apparent V-band magnitude 14.326 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-297 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-297 d sharing its stellar neighborhood alongside Kepler-297 b, Kepler-297 c.

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