Kepler-170 c
Astrophysical Synthesis & Habitability Characterization
Kepler-170 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-170, located approximately 2409.2 light-years (738.66 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0642% across the stellar disk), this world measures 2.86 Earth radii and has a measured mass of 8.55 Earth masses. Combining its mass and radius yields a mean bulk density of 2.02 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-170, Kepler-170 c completes one full revolution every 16.666 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 85.5 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 702 K (+429°C / +804°F) and receiving 50.68 S⊕ (~68,978 W/m²), Kepler-170 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-170 is classified as a stellar host with an effective photospheric temperature of 5,679 K, a radius of 1.035 R☉, a mass of 1.066 M☉, an estimated bolometric luminosity of 1 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.58 Gyr and a metallicity of [Fe/H] = 0.39 dex (metal-rich relative to the Sun). From Earth, Kepler-170 shines at apparent V-band magnitude 14.344 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-170 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-170 c sharing its stellar neighborhood alongside Kepler-170 b.
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-170 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,679 K |
| Stellar Radius | 1.0350 R☉ |
| Stellar Mass | 1.0660 M☉ |
| Bolometric Luminosity | 1 L☉ |
| Metallicity [Fe/H] | 0.390 dex |
| Stellar Age | 1.580 Gyr |
| Apparent Magnitude | V: 14.344 · G: 14.347 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.131000 AU |
| Orbital Period | 16.666 days |
| Mean Orbital Velocity | 85.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.1300° |
| Mean Bulk Density | 2.02 g/cm³ (19.3 km/s vesc) |
| Insolation Flux | 50.6820 S⊕ (~68,978 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2409.200 LY (738.657 pc) |