Kepler-847 b
Astrophysical Synthesis & Habitability Characterization
Kepler-847 b is a confirmed terrestrial exoplanet orbiting the star Kepler-847, located approximately 1673.5 light-years (513.1 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0197% across the stellar disk), this world measures 1.18 Earth radii and has a measured mass of 1.76 Earth masses. Combining its mass and radius yields a mean bulk density of 5.91 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.26 g⊕ (12.36 m/s²), and an escape velocity of 13.7 km/s.
In its orbital architecture around Kepler-847, Kepler-847 b completes one full revolution every 2.343 Earth days at a semi-major axis of 0.0315 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 146.2 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 1054 K (+781°C / +1438°F) and receiving 292.31 S⊕ (~397,834 W/m²), Kepler-847 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-847 is classified as a stellar host with an effective photospheric temperature of 4,940 K, a radius of 0.77 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.317 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.89 Gyr and a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, Kepler-847 shines at apparent V-band magnitude 14.998 (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-847 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,940 K |
| Stellar Radius | 0.7700 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.317 L☉ |
| Metallicity [Fe/H] | 0.150 dex |
| Stellar Age | 3.890 Gyr |
| Apparent Magnitude | V: 14.998 · G: 14.780 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.031500 AU |
| Orbital Period | 2.343 days |
| Mean Orbital Velocity | 146.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7000° |
| Mean Bulk Density | 5.91 g/cm³ (13.7 km/s vesc) |
| Insolation Flux | 292.3100 S⊕ (~397,834 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1673.500 LY (513.103 pc) |