Kepler-418 b
Astrophysical Synthesis & Habitability Characterization
Kepler-418 b is a confirmed gas giant exoplanet orbiting the star Kepler-418, located approximately 3269.8 light-years (1002.53 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 1.2798% across the stellar disk), this world measures 13.45 Earth radii (1.2 Jupiter radii) and has a measured mass of 349.611 Earth masses (1.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.79 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.93 g⊕ (18.93 m/s²), and an escape velocity of 57 km/s.
In its orbital architecture around Kepler-418, Kepler-418 b completes one full revolution every 86.679 Earth days at a semi-major axis of 0.39249 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 49.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.2 carries the world between 0.314 AU at periapsis and 0.471 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 434 K (+161°C / +322°F) and receiving 8.88 S⊕ (~12,082 W/m²), Kepler-418 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-418 is classified as a stellar host with an effective photospheric temperature of 5,820 K, a radius of 1.09 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 1.223 L☉. Stellar evolution modeling indicates an estimated stellar age of 7 Gyr and a metallicity of [Fe/H] = -0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-418 shines at apparent V-band magnitude 14.824 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-418 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-418 b sharing its stellar neighborhood alongside Kepler-418 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-418 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,820 K |
| Stellar Radius | 1.0900 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 1.223 L☉ |
| Metallicity [Fe/H] | -0.050 dex |
| Stellar Age | 7.000 Gyr |
| Apparent Magnitude | V: 14.824 · G: 14.649 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.392490 AU |
| Orbital Period | 86.679 days |
| Mean Orbital Velocity | 49.3 km/s |
| Orbital Eccentricity (e) | 0.20000 |
| Orbital Inclination (i) | 89.9520° |
| Mean Bulk Density | 0.79 g/cm³ (57 km/s vesc) |
| Insolation Flux | 8.8770 S⊕ (~12,082 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3269.800 LY (1002.530 pc) |