Kepler-458 c
Astrophysical Synthesis & Habitability Characterization
Kepler-458 c 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 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0302% across the stellar disk), this world measures 4.2 Earth radii (0.37 Jupiter radii) and has a measured mass of 16.4 Earth masses. Combining its mass and radius yields a mean bulk density of 1.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 22.1 km/s.
In its orbital architecture around KIC 9663113, Kepler-458 c completes one full revolution every 20.74 Earth days at a semi-major axis of 0.17012 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 89.2 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.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 798 K (+525°C / +977°F) and receiving 279.79 S⊕ (~380,790 W/m²), Kepler-458 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star KIC 9663113 is classified as a stellar host with an effective photospheric temperature of 6,117 K, a radius of 2.2156 R☉, a mass of 1.15 M☉, an estimated bolometric luminosity of 6.166 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.14 Gyr and a metallicity of [Fe/H] = 0.144 dex (metal-rich 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 Kepler-458 c sharing its stellar neighborhood alongside KIC 9663113 b.
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) | 6,117 K |
| Stellar Radius | 2.2156 R☉ |
| Stellar Mass | 1.1500 M☉ |
| Bolometric Luminosity | 6.166 L☉ |
| Metallicity [Fe/H] | 0.144 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) | 0.170120 AU |
| Orbital Period | 20.74 days |
| Mean Orbital Velocity | 89.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.2700° |
| Mean Bulk Density | 1.22 g/cm³ (22.1 km/s vesc) |
| Insolation Flux | 279.7870 S⊕ (~380,790 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 5201.300 LY (1594.740 pc) |