Kepler-1331 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1331 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1331, located approximately 1041.1 light-years (319.2 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0195% across the stellar disk), this world measures 1.05 Earth radii and has a measured mass of 1.16 Earth masses. Combining its mass and radius yields a mean bulk density of 5.53 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 11.8 km/s.
In its orbital architecture around Kepler-1331, Kepler-1331 b completes one full revolution every 0.789 Earth days at a semi-major axis of 0.0142 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 195.8 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 1244 K (+971°C / +1780°F) and receiving 547.29 S⊕ (~744,867 W/m²), Kepler-1331 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1331 is classified as a stellar host with an effective photospheric temperature of 4,508 K, a radius of 0.69 R☉, a mass of 0.72 M☉, an estimated bolometric luminosity of 0.176 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.17 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-1331 shines at apparent V-band magnitude 15.58 (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-1331 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,508 K |
| Stellar Radius | 0.6900 R☉ |
| Stellar Mass | 0.7200 M☉ |
| Bolometric Luminosity | 0.176 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 4.170 Gyr |
| Apparent Magnitude | V: 15.580 · G: 15.032 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.014200 AU |
| Orbital Period | 0.789 days |
| Mean Orbital Velocity | 195.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.5000° |
| Mean Bulk Density | 5.53 g/cm³ (11.8 km/s vesc) |
| Insolation Flux | 547.2940 S⊕ (~744,867 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1041.100 LY (319.197 pc) |