Kepler-511 c
Astrophysical Synthesis & Habitability Characterization
Kepler-511 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-511, located approximately 2126.5 light-years (652 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0742% across the stellar disk), this world measures 4.21 Earth radii (0.38 Jupiter radii) and has a measured mass of 16.5 Earth masses. Combining its mass and radius yields a mean bulk density of 1.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 22.1 km/s.
In its orbital architecture around Kepler-511, Kepler-511 c completes one full revolution every 26.629 Earth days at a semi-major axis of 0.17177 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 70.2 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 742 K (+469°C / +876°F) and receiving 101.60 S⊕ (~138,278 W/m²), Kepler-511 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-511 is classified as a stellar host with an effective photospheric temperature of 5,866 K, a radius of 1.417 R☉, a mass of 0.958 M☉, an estimated bolometric luminosity of 2.133 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.12 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, Kepler-511 shines at apparent V-band magnitude 12.711 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-511 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-511 c sharing its stellar neighborhood alongside Kepler-511 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-511 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,866 K |
| Stellar Radius | 1.4170 R☉ |
| Stellar Mass | 0.9580 M☉ |
| Bolometric Luminosity | 2.133 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | 9.120 Gyr |
| Apparent Magnitude | V: 12.711 · G: 12.583 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.171770 AU |
| Orbital Period | 26.629 days |
| Mean Orbital Velocity | 70.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9700° |
| Mean Bulk Density | 1.22 g/cm³ (22.1 km/s vesc) |
| Insolation Flux | 101.6000 S⊕ (~138,278 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2126.500 LY (651.999 pc) |