Kepler-312 c
Astrophysical Synthesis & Habitability Characterization
Kepler-312 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-312, located approximately 2601.8 light-years (797.72 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0388% across the stellar disk), this world measures 3.15 Earth radii (0.28 Jupiter radii) and has a measured mass of 10.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.78 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 20 km/s.
In its orbital architecture around Kepler-312, Kepler-312 c completes one full revolution every 19.747 Earth days at a semi-major axis of 0.153 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 84.3 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 754 K (+481°C / +898°F) and receiving 165.82 S⊕ (~225,686 W/m²), Kepler-312 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-312 is classified as a stellar host with an effective photospheric temperature of 6,115 K, a radius of 1.467 R☉, a mass of 1.314 M☉, an estimated bolometric luminosity of 2.7 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.88 Gyr and a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, Kepler-312 shines at apparent V-band magnitude 13.01 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-312 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-312 c sharing its stellar neighborhood alongside Kepler-312 b.
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-312 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,115 K |
| Stellar Radius | 1.4670 R☉ |
| Stellar Mass | 1.3140 M☉ |
| Bolometric Luminosity | 2.7 L☉ |
| Metallicity [Fe/H] | 0.150 dex |
| Stellar Age | 2.880 Gyr |
| Apparent Magnitude | V: 13.010 · G: 12.921 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.153000 AU |
| Orbital Period | 19.747 days |
| Mean Orbital Velocity | 84.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.0600° |
| Mean Bulk Density | 1.78 g/cm³ (20 km/s vesc) |
| Insolation Flux | 165.8240 S⊕ (~225,686 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2601.800 LY (797.720 pc) |