Kepler-27 c
Astrophysical Synthesis & Habitability Characterization
Kepler-27 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-27, located approximately 3406.2 light-years (1044.36 parsecs) from the Solar System. First announced in 2011 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.5797% across the stellar disk), this world measures 4.9 Earth radii (0.44 Jupiter radii) and has a measured mass of 4385.87 Earth masses (13.8 Jupiter masses). Combining its mass and radius yields a mean bulk density of 205.56 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 182.67 g⊕ (1791.38 m/s²), and an escape velocity of 334.7 km/s.
In its orbital architecture around Kepler-27, Kepler-27 c completes one full revolution every 31.331 Earth days at a semi-major axis of 0.191 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 66.3 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 481 K (+208°C / +406°F) and receiving 11.07 S⊕ (~15,062 W/m²), Kepler-27 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-27 is classified as a stellar host with an effective photospheric temperature of 5,400 K, a radius of 0.59 R☉, a mass of 0.65 M☉, an estimated bolometric luminosity of 0.266 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.62 Gyr and a metallicity of [Fe/H] = 0.41 dex (metal-rich relative to the Sun). From Earth, Kepler-27 shines at apparent V-band magnitude 15.822 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-27 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-27 c sharing its stellar neighborhood alongside Kepler-27 d, Kepler-27 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-27 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,400 K |
| Stellar Radius | 0.5900 R☉ |
| Stellar Mass | 0.6500 M☉ |
| Bolometric Luminosity | 0.266 L☉ |
| Metallicity [Fe/H] | 0.410 dex |
| Stellar Age | 1.620 Gyr |
| Apparent Magnitude | V: 15.822 · G: 15.816 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.191000 AU |
| Orbital Period | 31.331 days |
| Mean Orbital Velocity | 66.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.6200° |
| Mean Bulk Density | 205.56 g/cm³ (334.7 km/s vesc) |
| Insolation Flux | 11.0670 S⊕ (~15,062 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3406.200 LY (1044.360 pc) |