Kepler-746 b
Astrophysical Synthesis & Habitability Characterization
Kepler-746 b is a confirmed terrestrial exoplanet orbiting the star Kepler-746, located approximately 1467.7 light-years (450 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.012% across the stellar disk), this world measures 1.11 Earth radii and has a measured mass of 1.41 Earth masses. Combining its mass and radius yields a mean bulk density of 5.68 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.14 g⊕ (11.18 m/s²), and an escape velocity of 12.6 km/s.
In its orbital architecture around Kepler-746, Kepler-746 b completes one full revolution every 3.482 Earth days at a semi-major axis of 0.0435 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 135.9 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 1156 K (+883°C / +1621°F) and receiving 421.61 S⊕ (~573,811 W/m²), Kepler-746 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-746 is classified as a stellar host with an effective photospheric temperature of 5,418 K, a radius of 0.93 R☉, a mass of 0.91 M☉, an estimated bolometric luminosity of 0.669 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.71 Gyr and a metallicity of [Fe/H] = 0.09 dex (metal-rich relative to the Sun). From Earth, Kepler-746 shines at apparent V-band magnitude 13.785 (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-746 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,418 K |
| Stellar Radius | 0.9300 R☉ |
| Stellar Mass | 0.9100 M☉ |
| Bolometric Luminosity | 0.669 L☉ |
| Metallicity [Fe/H] | 0.090 dex |
| Stellar Age | 8.710 Gyr |
| Apparent Magnitude | V: 13.785 · G: 13.611 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.043500 AU |
| Orbital Period | 3.482 days |
| Mean Orbital Velocity | 135.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7100° |
| Mean Bulk Density | 5.68 g/cm³ (12.6 km/s vesc) |
| Insolation Flux | 421.6100 S⊕ (~573,811 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1467.700 LY (450.000 pc) |