Kepler-1920 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1920 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1920, located approximately 2889.5 light-years (885.91 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0544% across the stellar disk), this world measures 2.954 Earth radii and has a measured mass of 9.03 Earth masses. Combining its mass and radius yields a mean bulk density of 1.93 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.03 g⊕ (10.1 m/s²), and an escape velocity of 19.6 km/s.
In its orbital architecture around Kepler-1920, Kepler-1920 b completes one full revolution every 30.254 Earth days at a semi-major axis of 0.2043 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 73.5 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 660 K (+387°C / +729°F) and receiving 44.87 S⊕ (~61,068 W/m²), Kepler-1920 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1920 is classified as a stellar host with an effective photospheric temperature of 6,277 K, a radius of 1.161 R☉, a mass of 1.239 M☉, an estimated bolometric luminosity of 1.877 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, Kepler-1920 shines at apparent V-band magnitude 14.392 (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-1920 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,277 K |
| Stellar Radius | 1.1610 R☉ |
| Stellar Mass | 1.2390 M☉ |
| Bolometric Luminosity | 1.877 L☉ |
| Metallicity [Fe/H] | 0.210 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.392 · G: 14.306 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.204300 AU |
| Orbital Period | 30.254 days |
| Mean Orbital Velocity | 73.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9400° |
| Mean Bulk Density | 1.93 g/cm³ (19.6 km/s vesc) |
| Insolation Flux | 44.8700 S⊕ (~61,068 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2889.500 LY (885.913 pc) |