Kepler-413 b
Astrophysical Synthesis & Habitability Characterization
Kepler-413 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-413, located approximately 2764.3 light-years (847.54 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.2637% across the stellar disk), this world measures 4.347 Earth radii (0.39 Jupiter radii) and has a measured mass of 67 Earth masses (0.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.5 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 3.55 g⊕ (34.81 m/s²), and an escape velocity of 43.9 km/s.
In its orbital architecture around Kepler-413, Kepler-413 b completes one full revolution every 66.262 Earth days at a semi-major axis of 0.3553 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 58.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.1181 carries the world between 0.3133 AU at periapsis and 0.3973 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 4.347 R⊕, Kepler-413 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 Kepler-413 is classified as a stellar host with an effective photospheric temperature of 4,700 K, a radius of 0.7761 R☉, a mass of 0.82 M☉, an estimated bolometric luminosity of 0.264 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, Kepler-413 shines at apparent V-band magnitude 15.885 (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-413 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,700 K |
| Stellar Radius | 0.7761 R☉ |
| Stellar Mass | 0.8200 M☉ |
| Bolometric Luminosity | 0.264 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 15.885 · G: 15.594 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.355300 AU |
| Orbital Period | 66.262 days |
| Mean Orbital Velocity | 58.3 km/s |
| Orbital Eccentricity (e) | 0.11810 |
| Orbital Inclination (i) | 89.9290° |
| Mean Bulk Density | 4.5 g/cm³ (43.9 km/s vesc) |
| Insolation Flux | 2.9436 S⊕ (~4,006 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2764.300 LY (847.536 pc) |