Kepler-918 b
Astrophysical Synthesis & Habitability Characterization
Kepler-918 b is a confirmed super-earth exoplanet orbiting the star Kepler-918, located approximately 3343.2 light-years (1025.03 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0196% across the stellar disk), this world measures 1.74 Earth radii and has a measured mass of 3.68 Earth masses. Combining its mass and radius yields a mean bulk density of 3.85 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.22 g⊕ (11.96 m/s²), and an escape velocity of 16.3 km/s.
In its orbital architecture around Kepler-918, Kepler-918 b completes one full revolution every 4.854 Earth days at a semi-major axis of 0.0569 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 127.5 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.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1052 K (+779°C / +1434°F) and receiving 258.70 S⊕ (~352,093 W/m²), Kepler-918 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-918 is classified as a stellar host with an effective photospheric temperature of 6,028 K, a radius of 1.14 R☉, a mass of 1.11 M☉, an estimated bolometric luminosity of 1.54 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.24 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-918 shines at apparent V-band magnitude 15.064 (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 | Kepler-918 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,028 K |
| Stellar Radius | 1.1400 R☉ |
| Stellar Mass | 1.1100 M☉ |
| Bolometric Luminosity | 1.54 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 3.240 Gyr |
| Apparent Magnitude | V: 15.064 · G: 14.955 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.056900 AU |
| Orbital Period | 4.854 days |
| Mean Orbital Velocity | 127.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 77.9400° |
| Mean Bulk Density | 3.85 g/cm³ (16.3 km/s vesc) |
| Insolation Flux | 258.7020 S⊕ (~352,093 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3343.200 LY (1025.030 pc) |