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 0.5294% across the stellar disk), this world measures 7.119 Earth radii (0.64 Jupiter radii) and has a measured mass of 40.2 Earth masses (0.13 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.79 g⊕ (7.75 m/s²), and an escape velocity of 26.6 km/s.
In its orbital architecture around Kepler-297, Kepler-297 d completes one full revolution every 150.021 Earth days at a semi-major axis of 0.53898 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 39.1 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 7.119 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.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Kepler-297 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,618 K |
| Stellar Radius | 0.8970 R☉ |
| Stellar Mass | 0.8460 M☉ |
| Bolometric Luminosity | 0.719 L☉ |
| Metallicity [Fe/H] | -0.220 dex |
| Stellar Age | 1.900 Gyr |
| Apparent Magnitude | V: 14.326 · G: 14.192 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.538980 AU |
| Orbital Period | 150.021 days |
| Mean Orbital Velocity | 39.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4000° |
| Mean Bulk Density | 0.61 g/cm³ (26.6 km/s vesc) |
| Insolation Flux | 2.5000 S⊕ (~3,403 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2257.500 LY (692.140 pc) |