Kepler-1312 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1312 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1312, located approximately 975.5 light-years (299.1 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0438% across the stellar disk), this world measures 2.1 Earth radii and has a measured mass of 5.06 Earth masses. Combining its mass and radius yields a mean bulk density of 3.01 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.4 km/s.
In its orbital architecture around Kepler-1312, Kepler-1312 b completes one full revolution every 5.448 Earth days at a semi-major axis of 0.06053 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 120.9 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 978 K (+705°C / +1301°F) and receiving 219.12 S⊕ (~298,218 W/m²), Kepler-1312 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1312 is classified as a stellar host with an effective photospheric temperature of 5,719 K, a radius of 0.92 R☉, a mass of 0.99 M☉, an estimated bolometric luminosity of 0.812 L☉. Stellar evolution modeling indicates an estimated stellar age of 2 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-1312 shines at apparent V-band magnitude 12.491 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1312 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-1312 b sharing its stellar neighborhood alongside Kepler-1312 c.
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-1312 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,719 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 0.9900 M☉ |
| Bolometric Luminosity | 0.812 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 2.000 Gyr |
| Apparent Magnitude | V: 12.491 · G: 12.378 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.060530 AU |
| Orbital Period | 5.448 days |
| Mean Orbital Velocity | 120.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.7100° |
| Mean Bulk Density | 3.01 g/cm³ (17.4 km/s vesc) |
| Insolation Flux | 219.1170 S⊕ (~298,218 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 975.500 LY (299.104 pc) |