Kepler-136 c
Astrophysical Synthesis & Habitability Characterization
Kepler-136 c is a confirmed super-earth exoplanet orbiting the star Kepler-136, located approximately 1372.5 light-years (420.82 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0181% across the stellar disk), this world measures 1.99 Earth radii and has a measured mass of 4.62 Earth masses. Combining its mass and radius yields a mean bulk density of 3.23 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 17 km/s.
In its orbital architecture around Kepler-136, Kepler-136 c completes one full revolution every 16.399 Earth days at a semi-major axis of 0.133 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 88.2 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 847 K (+574°C / +1065°F) and receiving 162.04 S⊕ (~220,542 W/m²), Kepler-136 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-136 is classified as a stellar host with an effective photospheric temperature of 6,165 K, a radius of 1.355 R☉, a mass of 1.204 M☉, an estimated bolometric luminosity of 2.38 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.75 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-136 shines at apparent V-band magnitude 11.822 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-136 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-136 c sharing its stellar neighborhood alongside Kepler-136 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-136 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,165 K |
| Stellar Radius | 1.3550 R☉ |
| Stellar Mass | 1.2040 M☉ |
| Bolometric Luminosity | 2.38 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 2.750 Gyr |
| Apparent Magnitude | V: 11.822 · G: 11.754 |
| System Architecture | 2 Stars, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.133000 AU |
| Orbital Period | 16.399 days |
| Mean Orbital Velocity | 88.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8200° |
| Mean Bulk Density | 3.23 g/cm³ (17 km/s vesc) |
| Insolation Flux | 162.0440 S⊕ (~220,542 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1372.500 LY (420.818 pc) |