KOI-3680 b
Astrophysical Synthesis & Habitability Characterization
KOI-3680 b is a confirmed gas giant exoplanet orbiting the star KOI-3680, located approximately 3007.1 light-years (921.99 parsecs) from the Solar System. First announced in 2018 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 1.1231% across the stellar disk), this world measures 11.097 Earth radii (0.99 Jupiter radii) and has a measured mass of 613.412 Earth masses (1.93 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.48 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 4.98 g⊕ (48.84 m/s²), and an escape velocity of 83.2 km/s.
In its orbital architecture around KOI-3680, KOI-3680 b completes one full revolution every 141.242 Earth days at a semi-major axis of 0.534 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 41.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.496, swinging from 0.2691 AU at periapsis out to 0.7989 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 11.097 R⊕, KOI-3680 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 KOI-3680 is classified as a stellar host with an effective photospheric temperature of 5,830 K, a radius of 0.96 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 0.955 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = 0.16 dex (metal-rich relative to the Sun). From Earth, KOI-3680 shines at apparent V-band magnitude 14.616 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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 | KOI-3680 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,830 K |
| Stellar Radius | 0.9600 R☉ |
| Stellar Mass | 1.0100 M☉ |
| Bolometric Luminosity | 0.955 L☉ |
| Metallicity [Fe/H] | 0.160 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 14.616 · G: 14.503 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.534000 AU |
| Orbital Period | 141.242 days |
| Mean Orbital Velocity | 41.1 km/s |
| Orbital Eccentricity (e) | 0.49600 |
| Orbital Inclination (i) | 89.8920° |
| Mean Bulk Density | 2.48 g/cm³ (83.2 km/s vesc) |
| Insolation Flux | 3.3000 S⊕ (~4,491 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3007.100 LY (921.986 pc) |