Kepler-1307 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1307 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1307, located approximately 3309.2 light-years (1014.62 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.044% across the stellar disk), this world measures 2.47 Earth radii and has a measured mass of 6.66 Earth masses. Combining its mass and radius yields a mean bulk density of 2.44 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.09 g⊕ (10.69 m/s²), and an escape velocity of 18.4 km/s.
In its orbital architecture around Kepler-1307, Kepler-1307 b completes one full revolution every 18.016 Earth days at a semi-major axis of 0.1369 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.7 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 768 K (+495°C / +923°F) and receiving 41.19 S⊕ (~56,053 W/m²), Kepler-1307 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1307 is classified as a stellar host with an effective photospheric temperature of 5,884 K, a radius of 1.08 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.254 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.07 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1307 shines at apparent V-band magnitude 15.636 (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-1307 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,884 K |
| Stellar Radius | 1.0800 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 1.254 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 4.070 Gyr |
| Apparent Magnitude | V: 15.636 · G: 15.380 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.136900 AU |
| Orbital Period | 18.016 days |
| Mean Orbital Velocity | 82.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9600° |
| Mean Bulk Density | 2.44 g/cm³ (18.4 km/s vesc) |
| Insolation Flux | 41.1850 S⊕ (~56,053 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3309.200 LY (1014.620 pc) |