Kepler-599 b
Astrophysical Synthesis & Habitability Characterization
Kepler-599 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-599, located approximately 1821.6 light-years (558.52 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1086% across the stellar disk), this world measures 2.84 Earth radii and has a measured mass of 8.45 Earth masses. Combining its mass and radius yields a mean bulk density of 2.03 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 19.3 km/s.
In its orbital architecture around Kepler-599, Kepler-599 b completes one full revolution every 15.656 Earth days at a semi-major axis of 0.1128 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.4 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 623 K (+350°C / +662°F) and receiving 24.47 S⊕ (~33,300 W/m²), Kepler-599 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-599 is classified as a stellar host with an effective photospheric temperature of 5,127 K, a radius of 0.79 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.387 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.01 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-599 shines at apparent V-band magnitude 15.067 (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-599 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,127 K |
| Stellar Radius | 0.7900 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.387 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 5.010 Gyr |
| Apparent Magnitude | V: 15.067 · G: 14.948 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.112800 AU |
| Orbital Period | 15.656 days |
| Mean Orbital Velocity | 78.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4200° |
| Mean Bulk Density | 2.03 g/cm³ (19.3 km/s vesc) |
| Insolation Flux | 24.4670 S⊕ (~33,300 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1821.600 LY (558.517 pc) |