Kepler-199 b
Astrophysical Synthesis & Habitability Characterization
Kepler-199 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-199, located approximately 1699.4 light-years (521.05 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0869% across the stellar disk), this world measures 3.11 Earth radii (0.28 Jupiter radii) and has a measured mass of 9.85 Earth masses. Combining its mass and radius yields a mean bulk density of 1.81 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 19.9 km/s.
In its orbital architecture around Kepler-199, Kepler-199 b completes one full revolution every 23.638 Earth days at a semi-major axis of 0.158 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 72.7 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 595 K (+322°C / +612°F) and receiving 31.68 S⊕ (~43,115 W/m²), Kepler-199 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-199 is classified as a stellar host with an effective photospheric temperature of 5,644 K, a radius of 0.967 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 0.851 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.45 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-199 shines at apparent V-band magnitude 13.796 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-199 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-199 b sharing its stellar neighborhood alongside Kepler-199 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-199 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,644 K |
| Stellar Radius | 0.9670 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 0.851 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 1.450 Gyr |
| Apparent Magnitude | V: 13.796 · G: 13.597 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.158000 AU |
| Orbital Period | 23.638 days |
| Mean Orbital Velocity | 72.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9700° |
| Mean Bulk Density | 1.81 g/cm³ (19.9 km/s vesc) |
| Insolation Flux | 31.6790 S⊕ (~43,115 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1699.400 LY (521.054 pc) |