Kepler-118 b
Astrophysical Synthesis & Habitability Characterization
Kepler-118 b is a confirmed super-earth exoplanet orbiting the star Kepler-118, located approximately 1872.9 light-years (574.23 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.027% across the stellar disk), this world measures 1.96 Earth radii and has a measured mass of 4.5 Earth masses. Combining its mass and radius yields a mean bulk density of 3.3 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 16.9 km/s.
In its orbital architecture around Kepler-118, Kepler-118 b completes one full revolution every 7.518 Earth days at a semi-major axis of 0.073 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 105.6 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 784 K (+511°C / +952°F) and receiving 79.75 S⊕ (~108,544 W/m²), Kepler-118 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-118 is classified as a stellar host with an effective photospheric temperature of 5,274 K, a radius of 1.094 R☉, a mass of 0.811 M☉, an estimated bolometric luminosity of 0.831 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.9 Gyr and a metallicity of [Fe/H] = 0.18 dex (metal-rich relative to the Sun). From Earth, Kepler-118 shines at apparent V-band magnitude 14.867 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-118 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-118 b sharing its stellar neighborhood alongside Kepler-118 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-118 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,274 K |
| Stellar Radius | 1.0940 R☉ |
| Stellar Mass | 0.8110 M☉ |
| Bolometric Luminosity | 0.831 L☉ |
| Metallicity [Fe/H] | 0.180 dex |
| Stellar Age | 13.900 Gyr |
| Apparent Magnitude | V: 14.867 · G: 14.719 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.073000 AU |
| Orbital Period | 7.518 days |
| Mean Orbital Velocity | 105.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6300° |
| Mean Bulk Density | 3.3 g/cm³ (16.9 km/s vesc) |
| Insolation Flux | 79.7530 S⊕ (~108,544 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1872.900 LY (574.228 pc) |