KIC 9663113 b
Astrophysical Synthesis & Habitability Characterization
KIC 9663113 b is a confirmed sub-neptune exoplanet orbiting the star KIC 9663113, located approximately 5201.3 light-years (1594.74 parsecs) from the Solar System. First announced in 2015 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1676% across the stellar disk), this world measures 4.6 Earth radii (0.41 Jupiter radii) and has a measured mass of 19.2 Earth masses. Combining its mass and radius yields a mean bulk density of 1.09 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.91 g⊕ (8.92 m/s²), and an escape velocity of 22.9 km/s.
In its orbital architecture around KIC 9663113, KIC 9663113 b completes one full revolution every 572.385 Earth days (1.57Julian years) at a semi-major axis of 1.55346 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 29.5 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 4.600 R⊕, KIC 9663113 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 KIC 9663113 is classified as a stellar host with an effective photospheric temperature of 6,065 K, a radius of 1.03 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 1.288 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.14 Gyr and a metallicity of [Fe/H] = -0.28 dex (metal-poor relative to the Sun). From Earth, KIC 9663113 shines at apparent V-band magnitude 14.027 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KIC 9663113 system is a multi-planet architecture hosting 2 confirmed worlds, with KIC 9663113 b sharing its stellar neighborhood alongside Kepler-458 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 | KIC 9663113 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,065 K |
| Stellar Radius | 1.0300 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 1.288 L☉ |
| Metallicity [Fe/H] | -0.280 dex |
| Stellar Age | 2.140 Gyr |
| Apparent Magnitude | V: 14.027 · G: 13.908 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.553460 AU |
| Orbital Period | 572.385 days |
| Mean Orbital Velocity | 29.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7680° |
| Mean Bulk Density | 1.09 g/cm³ (22.9 km/s vesc) |
| Insolation Flux | 3.3560 S⊕ (~4,568 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 5201.300 LY (1594.740 pc) |