KOI-884 e
Astrophysical Synthesis & Habitability Characterization
KOI-884 e is a confirmed gas giant exoplanet orbiting the star Kepler-247, located approximately 2164.7 light-years (663.71 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit Timing Variations detection technique (producing an estimated primary transit depth of 1.2319% across the stellar disk), this world measures 9.54 Earth radii (0.85 Jupiter radii) and has a measured mass of 66.054 Earth masses (0.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.42 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 29.4 km/s.
In its orbital architecture around Kepler-247, KOI-884 e completes one full revolution every 31.102 Earth days. With a near-circular eccentricity of e = 0.0415, the planet experiences minimal orbital distance variation.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 9.540 R⊕, KOI-884 e 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-247 is classified as an orange K-type star of spectral type K with an effective photospheric temperature of 5,060 K, a radius of 0.788 R☉, a mass of 0.887 M☉, an estimated bolometric luminosity of 0.365 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.14 Gyr and a metallicity of [Fe/H] = 0.3 dex (metal-rich relative to the Sun). From Earth, Kepler-247 shines at apparent V-band magnitude 15.199 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-247 system is a multi-planet architecture hosting 4 confirmed worlds, with KOI-884 e sharing its stellar neighborhood alongside Kepler-247 b, Kepler-247 c, Kepler-247 d.
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-247 |
| Spectral Type | K |
| Effective Temp (Teff) | 5,060 K |
| Stellar Radius | 0.7880 R☉ |
| Stellar Mass | 0.8870 M☉ |
| Bolometric Luminosity | 0.365 L☉ |
| Metallicity [Fe/H] | 0.300 dex |
| Stellar Age | 2.140 Gyr |
| Apparent Magnitude | V: 15.199 · G: 15.047 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 31.102 days |
| Orbital Eccentricity (e) | 0.04150 |
| Orbital Inclination (i) | 88.7389° |
| Mean Bulk Density | 0.42 g/cm³ (29.4 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2164.700 LY (663.711 pc) |