Kepler-920 c
Astrophysical Synthesis & Habitability Characterization
Kepler-920 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-920, located approximately 3267 light-years (1001.68 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.168% across the stellar disk), this world measures 3.8 Earth radii (0.34 Jupiter radii) and has a measured mass of 13.8 Earth masses. Combining its mass and radius yields a mean bulk density of 1.39 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.96 g⊕ (9.41 m/s²), and an escape velocity of 21.3 km/s.
In its orbital architecture around Kepler-920, Kepler-920 c completes one full revolution every 100.827 Earth days at a semi-major axis of 0.4029 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 43.5 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 364 K (+91°C / +196°F) and receiving 3.99 S⊕ (~5,425 W/m²), Kepler-920 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-920 is classified as a stellar host with an effective photospheric temperature of 5,403 K, a radius of 0.85 R☉, a mass of 0.89 M☉, an estimated bolometric luminosity of 0.552 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.37 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-920 shines at apparent V-band magnitude 15.492 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-920 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-920 c sharing its stellar neighborhood alongside Kepler-920 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-920 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,403 K |
| Stellar Radius | 0.8500 R☉ |
| Stellar Mass | 0.8900 M☉ |
| Bolometric Luminosity | 0.552 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 4.370 Gyr |
| Apparent Magnitude | V: 15.492 · G: 15.268 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.402900 AU |
| Orbital Period | 100.827 days |
| Mean Orbital Velocity | 43.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4700° |
| Mean Bulk Density | 1.39 g/cm³ (21.3 km/s vesc) |
| Insolation Flux | 3.9860 S⊕ (~5,425 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3267.000 LY (1001.680 pc) |