Kepler-194 c
Astrophysical Synthesis & Habitability Characterization
Kepler-194 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-194, located approximately 3581.1 light-years (1097.97 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0537% across the stellar disk), this world measures 2.59 Earth radii and has a measured mass of 7.22 Earth masses. Combining its mass and radius yields a mean bulk density of 2.29 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.7 km/s.
In its orbital architecture around Kepler-194, Kepler-194 c completes one full revolution every 17.308 Earth days at a semi-major axis of 0.131 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.3 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 815 K (+542°C / +1008°F) and receiving 56.96 S⊕ (~77,516 W/m²), Kepler-194 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-194 is classified as a stellar host with an effective photospheric temperature of 6,089 K, a radius of 1.025 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 1.296 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.5 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-194 shines at apparent V-band magnitude 14.969 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-194 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-194 c sharing its stellar neighborhood alongside Kepler-194 b, Kepler-194 d.
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-194 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,089 K |
| Stellar Radius | 1.0250 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 1.296 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 2.500 Gyr |
| Apparent Magnitude | V: 14.969 · G: 14.912 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.131000 AU |
| Orbital Period | 17.308 days |
| Mean Orbital Velocity | 82.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 2.29 g/cm³ (18.7 km/s vesc) |
| Insolation Flux | 56.9550 S⊕ (~77,516 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3581.100 LY (1097.970 pc) |