Kepler-205 c
Astrophysical Synthesis & Habitability Characterization
Kepler-205 c is a confirmed super-earth exoplanet orbiting the star Kepler-205, located approximately 520.9 light-years (159.72 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0758% across the stellar disk), this world measures 1.64 Earth radii and has a measured mass of 3.33 Earth masses. Combining its mass and radius yields a mean bulk density of 4.16 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.24 g⊕ (12.16 m/s²), and an escape velocity of 15.9 km/s.
In its orbital architecture around Kepler-205, Kepler-205 c completes one full revolution every 20.307 Earth days at a semi-major axis of 0.122 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 65.4 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 389 K (+116°C / +241°F) and receiving 7.14 S⊕ (~9,718 W/m²), Kepler-205 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-205 is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 4,321 K, a radius of 0.546 R☉, a mass of 0.592 M☉, an estimated bolometric luminosity of 0.093 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.42 Gyr and a metallicity of [Fe/H] = -0.125 dex (metal-poor relative to the Sun). From Earth, Kepler-205 shines at apparent V-band magnitude 13.779 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-205 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-205 c sharing its stellar neighborhood alongside Kepler-205 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-205 |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 4,321 K |
| Stellar Radius | 0.5460 R☉ |
| Stellar Mass | 0.5920 M☉ |
| Bolometric Luminosity | 0.093 L☉ |
| Metallicity [Fe/H] | -0.125 dex |
| Stellar Age | 4.420 Gyr |
| Apparent Magnitude | V: 13.779 · G: 13.495 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.122000 AU |
| Orbital Period | 20.307 days |
| Mean Orbital Velocity | 65.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.0000° |
| Mean Bulk Density | 4.16 g/cm³ (15.9 km/s vesc) |
| Insolation Flux | 7.1400 S⊕ (~9,718 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 520.900 LY (159.720 pc) |