Kepler-368 c
Astrophysical Synthesis & Habitability Characterization
Kepler-368 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-368, located approximately 2514.6 light-years (770.98 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.031% across the stellar disk), this world measures 3.88 Earth radii (0.35 Jupiter radii) and has a measured mass of 14.3 Earth masses. Combining its mass and radius yields a mean bulk density of 1.35 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 21.5 km/s.
In its orbital architecture around Kepler-368, Kepler-368 c completes one full revolution every 72.379 Earth days at a semi-major axis of 0.36 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 54.1 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 575 K (+302°C / +576°F) and receiving 28.68 S⊕ (~39,035 W/m²), Kepler-368 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-368 is classified as a stellar host with an effective photospheric temperature of 5,502 K, a radius of 2.019 R☉, a mass of 1.165 M☉, an estimated bolometric luminosity of 3.352 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.46 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-368 shines at apparent V-band magnitude 12.946 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-368 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-368 c sharing its stellar neighborhood alongside Kepler-368 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-368 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,502 K |
| Stellar Radius | 2.0190 R☉ |
| Stellar Mass | 1.1650 M☉ |
| Bolometric Luminosity | 3.352 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 6.460 Gyr |
| Apparent Magnitude | V: 12.946 · G: 12.838 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.360000 AU |
| Orbital Period | 72.379 days |
| Mean Orbital Velocity | 54.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.9500° |
| Mean Bulk Density | 1.35 g/cm³ (21.5 km/s vesc) |
| Insolation Flux | 28.6810 S⊕ (~39,035 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2514.600 LY (770.978 pc) |