Kepler-1857 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1857 b is a confirmed super-earth exoplanet orbiting the star Kepler-1857, located approximately 2783 light-years (853.28 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.032% across the stellar disk), this world measures 1.961 Earth radii and has a measured mass of 4.5 Earth masses. Combining its mass and radius yields a mean bulk density of 3.29 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 16.9 km/s.
In its orbital architecture around Kepler-1857, Kepler-1857 b completes one full revolution every 8.943 Earth days at a semi-major axis of 0.08308 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 101.1 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 946 K (+673°C / +1243°F) and receiving 217.40 S⊕ (~295,881 W/m²), Kepler-1857 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1857 is classified as a stellar host with an effective photospheric temperature of 6,074 K, a radius of 1.005 R☉, a mass of 0.873 M☉, an estimated bolometric luminosity of 1.233 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.94 Gyr and a metallicity of [Fe/H] = -0.54 dex (metal-poor relative to the Sun). From Earth, Kepler-1857 shines at apparent V-band magnitude 14.36 (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-1857 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,074 K |
| Stellar Radius | 1.0050 R☉ |
| Stellar Mass | 0.8730 M☉ |
| Bolometric Luminosity | 1.233 L☉ |
| Metallicity [Fe/H] | -0.540 dex |
| Stellar Age | 7.940 Gyr |
| Apparent Magnitude | V: 14.360 · G: 14.149 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.083080 AU |
| Orbital Period | 8.943 days |
| Mean Orbital Velocity | 101.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6600° |
| Mean Bulk Density | 3.29 g/cm³ (16.9 km/s vesc) |
| Insolation Flux | 217.4000 S⊕ (~295,881 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2783.000 LY (853.275 pc) |