Kepler-1850 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1850 b is a confirmed sub-earth exoplanet orbiting the star Kepler-1850, located approximately 816 light-years (250.2 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0124% across the stellar disk), this world measures 0.729 Earth radii and has a measured mass of 0.313 Earth masses. Combining its mass and radius yields a mean bulk density of 4.45 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.59 g⊕ (5.79 m/s²), and an escape velocity of 7.3 km/s.
In its orbital architecture around Kepler-1850, Kepler-1850 b completes one full revolution every 1.386 Earth days at a semi-major axis of 0.0206 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 161.7 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 1008 K (+735°C / +1355°F) and receiving 245.15 S⊕ (~333,649 W/m²), Kepler-1850 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1850 is classified as a stellar host with an effective photospheric temperature of 4,239 K, a radius of 0.6 R☉, a mass of 0.611 M☉, an estimated bolometric luminosity of 0.104 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.8 Gyr and a metallicity of [Fe/H] = -0.22 dex (metal-poor relative to the Sun). From Earth, Kepler-1850 shines at apparent V-band magnitude 14.44 (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-1850 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,239 K |
| Stellar Radius | 0.6000 R☉ |
| Stellar Mass | 0.6110 M☉ |
| Bolometric Luminosity | 0.104 L☉ |
| Metallicity [Fe/H] | -0.220 dex |
| Stellar Age | 13.800 Gyr |
| Apparent Magnitude | V: 14.440 · G: 14.088 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.020600 AU |
| Orbital Period | 1.386 days |
| Mean Orbital Velocity | 161.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7200° |
| Mean Bulk Density | 4.45 g/cm³ (7.3 km/s vesc) |
| Insolation Flux | 245.1500 S⊕ (~333,649 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 816.000 LY (250.199 pc) |