Kepler-608 b
Astrophysical Synthesis & Habitability Characterization
Kepler-608 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-608, located approximately 3087.7 light-years (946.68 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1092% across the stellar disk), this world measures 3.64 Earth radii (0.32 Jupiter radii) and has a measured mass of 12.9 Earth masses. Combining its mass and radius yields a mean bulk density of 1.47 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.97 g⊕ (9.51 m/s²), and an escape velocity of 21.1 km/s.
In its orbital architecture around Kepler-608, Kepler-608 b completes one full revolution every 6.413 Earth days at a semi-major axis of 0.0685 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 116.2 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 1069 K (+796°C / +1465°F) and receiving 270.16 S⊕ (~367,690 W/m²), Kepler-608 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-608 is classified as a stellar host with an effective photospheric temperature of 5,820 K, a radius of 1.01 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 1.05 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.8 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-608 shines at apparent V-band magnitude 14.84 (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-608 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,820 K |
| Stellar Radius | 1.0100 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 1.05 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 3.800 Gyr |
| Apparent Magnitude | V: 14.840 · G: 14.657 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.068500 AU |
| Orbital Period | 6.413 days |
| Mean Orbital Velocity | 116.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.1100° |
| Mean Bulk Density | 1.47 g/cm³ (21.1 km/s vesc) |
| Insolation Flux | 270.1620 S⊕ (~367,690 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3087.700 LY (946.683 pc) |