Kepler-36 c
Astrophysical Synthesis & Habitability Characterization
Kepler-36 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-36, located approximately 1722 light-years (527.96 parsecs) from the Solar System. First announced in 2012 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0426% across the stellar disk), this world measures 3.679 Earth radii (0.33 Jupiter radii) and has a measured mass of 7.13 Earth masses. Combining its mass and radius yields a mean bulk density of 0.79 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.53 g⊕ (5.2 m/s²), and an escape velocity of 15.6 km/s.
In its orbital architecture around Kepler-36, Kepler-36 c completes one full revolution every 16.219 Earth days at a semi-major axis of 0.12692 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 85.1 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 928 K (+655°C / +1211°F) and receiving 191.00 S⊕ (~259,951 W/m²), Kepler-36 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-36 is classified as a stellar host with an effective photospheric temperature of 5,979 K, a radius of 1.634 R☉, a mass of 1.034 M☉, an estimated bolometric luminosity of 3.061 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.41 Gyr and a metallicity of [Fe/H] = -0.18 dex (metal-poor relative to the Sun). From Earth, Kepler-36 shines at apparent V-band magnitude 11.941 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-36 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-36 c sharing its stellar neighborhood alongside Kepler-36 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-36 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,979 K |
| Stellar Radius | 1.6340 R☉ |
| Stellar Mass | 1.0340 M☉ |
| Bolometric Luminosity | 3.061 L☉ |
| Metallicity [Fe/H] | -0.180 dex |
| Stellar Age | 7.410 Gyr |
| Apparent Magnitude | V: 11.941 · G: 12.077 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.126920 AU |
| Orbital Period | 16.219 days |
| Mean Orbital Velocity | 85.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.3600° |
| Mean Bulk Density | 0.79 g/cm³ (15.6 km/s vesc) |
| Insolation Flux | 191.0000 S⊕ (~259,951 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1722.000 LY (527.956 pc) |