Kepler-931 b
Astrophysical Synthesis & Habitability Characterization
Kepler-931 b is a confirmed super-earth exoplanet orbiting the star Kepler-931, located approximately 1598.2 light-years (490 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0227% across the stellar disk), this world measures 1.33 Earth radii and has a measured mass of 2.33 Earth masses. Combining its mass and radius yields a mean bulk density of 5.46 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around Kepler-931, Kepler-931 b completes one full revolution every 8.038 Earth days at a semi-major axis of 0.0719 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 97.3 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 744 K (+471°C / +880°F) and receiving 72.44 S⊕ (~98,591 W/m²), Kepler-931 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-931 is classified as a stellar host with an effective photospheric temperature of 5,241 K, a radius of 0.81 R☉, a mass of 0.86 M☉, an estimated bolometric luminosity of 0.444 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.68 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-931 shines at apparent V-band magnitude 14.643 (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-931 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,241 K |
| Stellar Radius | 0.8100 R☉ |
| Stellar Mass | 0.8600 M☉ |
| Bolometric Luminosity | 0.444 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 4.680 Gyr |
| Apparent Magnitude | V: 14.643 · G: 14.488 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.071900 AU |
| Orbital Period | 8.038 days |
| Mean Orbital Velocity | 97.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.2900° |
| Mean Bulk Density | 5.46 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 72.4400 S⊕ (~98,591 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1598.200 LY (490.000 pc) |