Kepler-339 c
Astrophysical Synthesis & Habitability Characterization
Kepler-339 c is a confirmed terrestrial exoplanet orbiting the star Kepler-339, located approximately 2011.2 light-years (616.64 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0173% across the stellar disk), this world measures 1.15 Earth radii and has a measured mass of 7.3 Earth masses. Combining its mass and radius yields a mean bulk density of 26.47 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 5.52 g⊕ (54.13 m/s²), and an escape velocity of 28.2 km/s.
In its orbital architecture around Kepler-339, Kepler-339 c completes one full revolution every 6.988 Earth days at a semi-major axis of 0.069 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 107.4 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 914 K (+641°C / +1186°F) and receiving 101.84 S⊕ (~138,606 W/m²), Kepler-339 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-339 is classified as a stellar host with an effective photospheric temperature of 5,631 K, a radius of 0.802 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.58 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.98 Gyr and a metallicity of [Fe/H] = 0.033 dex (near-solar heavy-element abundance). From Earth, Kepler-339 shines at apparent V-band magnitude 14.706 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-339 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-339 c sharing its stellar neighborhood alongside Kepler-339 b, Kepler-339 d.
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-339 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,631 K |
| Stellar Radius | 0.8020 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.58 L☉ |
| Metallicity [Fe/H] | 0.033 dex |
| Stellar Age | 0.980 Gyr |
| Apparent Magnitude | V: 14.706 · G: 14.513 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.069000 AU |
| Orbital Period | 6.988 days |
| Mean Orbital Velocity | 107.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9200° |
| Mean Bulk Density | 26.47 g/cm³ (28.2 km/s vesc) |
| Insolation Flux | 101.8410 S⊕ (~138,606 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2011.200 LY (616.637 pc) |