Kepler-911 b
Astrophysical Synthesis & Habitability Characterization
Kepler-911 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-911, located approximately 1814 light-years (556.17 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0143% across the stellar disk), this world measures 2.6 Earth radii and has a measured mass of 7.27 Earth masses. Combining its mass and radius yields a mean bulk density of 2.28 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.7 km/s.
In its orbital architecture around Kepler-911, Kepler-911 b completes one full revolution every 20.311 Earth days at a semi-major axis of 0.15594 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.5 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 931 K (+658°C / +1216°F) and receiving 198.73 S⊕ (~270,465 W/m²), Kepler-911 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-911 is classified as a stellar host with an effective photospheric temperature of 6,112 K, a radius of 1.99 R☉, a mass of 1.34 M☉, an estimated bolometric luminosity of 4.958 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-911 shines at apparent V-band magnitude 11.767 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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-911 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,112 K |
| Stellar Radius | 1.9900 R☉ |
| Stellar Mass | 1.3400 M☉ |
| Bolometric Luminosity | 4.958 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 3.550 Gyr |
| Apparent Magnitude | V: 11.767 · G: 11.830 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.155940 AU |
| Orbital Period | 20.311 days |
| Mean Orbital Velocity | 83.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9000° |
| Mean Bulk Density | 2.28 g/cm³ (18.7 km/s vesc) |
| Insolation Flux | 198.7250 S⊕ (~270,465 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1814.000 LY (556.168 pc) |