Kepler-197 c
Astrophysical Synthesis & Habitability Characterization
Kepler-197 c is a confirmed terrestrial exoplanet orbiting the star Kepler-197, located approximately 1078.2 light-years (330.58 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0101% across the stellar disk), this world measures 1.23 Earth radii and has a measured mass of 5.3 Earth masses. Combining its mass and radius yields a mean bulk density of 15.7 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 3.5 g⊕ (34.32 m/s²), and an escape velocity of 23.2 km/s.
In its orbital architecture around Kepler-197, Kepler-197 c completes one full revolution every 10.35 Earth days at a semi-major axis of 0.09 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 94.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.08 carries the world between 0.0828 AU at periapsis and 0.0972 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 930 K (+657°C / +1215°F) and receiving 189.97 S⊕ (~258,542 W/m²), Kepler-197 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-197 is classified as a stellar host with an effective photospheric temperature of 6,004 K, a radius of 1.12 R☉, a mass of 0.857 M☉, an estimated bolometric luminosity of 1.462 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.37 Gyr and a metallicity of [Fe/H] = -0.441 dex (metal-poor relative to the Sun). From Earth, Kepler-197 shines at apparent V-band magnitude 11.775 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-197 system is a multi-planet architecture hosting 4 confirmed worlds, with Kepler-197 c sharing its stellar neighborhood alongside Kepler-197 b, Kepler-197 d, Kepler-197 e.
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-197 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,004 K |
| Stellar Radius | 1.1200 R☉ |
| Stellar Mass | 0.8570 M☉ |
| Bolometric Luminosity | 1.462 L☉ |
| Metallicity [Fe/H] | -0.441 dex |
| Stellar Age | 5.370 Gyr |
| Apparent Magnitude | V: 11.775 · G: 11.780 |
| System Architecture | 2 Stars, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.090000 AU |
| Orbital Period | 10.35 days |
| Mean Orbital Velocity | 94.6 km/s |
| Orbital Eccentricity (e) | 0.08000 |
| Orbital Inclination (i) | 83.5100° |
| Mean Bulk Density | 15.7 g/cm³ (23.2 km/s vesc) |
| Insolation Flux | 189.9650 S⊕ (~258,542 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1078.200 LY (330.575 pc) |