Kepler-337 c
Astrophysical Synthesis & Habitability Characterization
Kepler-337 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-337, located approximately 2211.3 light-years (677.98 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0114% across the stellar disk), this world measures 2.05 Earth radii and has a measured mass of 4.86 Earth masses. Combining its mass and radius yields a mean bulk density of 3.11 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.16 g⊕ (11.38 m/s²), and an escape velocity of 17.2 km/s.
In its orbital architecture around Kepler-337, Kepler-337 c completes one full revolution every 9.693 Earth days at a semi-major axis of 0.093 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 104.4 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 1017 K (+744°C / +1371°F) and receiving 376.21 S⊕ (~512,022 W/m²), Kepler-337 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-337 is classified as a stellar host with an effective photospheric temperature of 5,684 K, a radius of 1.761 R☉, a mass of 1.081 M☉, an estimated bolometric luminosity of 2.904 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.94 Gyr and a metallicity of [Fe/H] = 0.07 dex (metal-rich relative to the Sun). From Earth, Kepler-337 shines at apparent V-band magnitude 12.799 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-337 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-337 c sharing its stellar neighborhood alongside Kepler-337 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-337 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,684 K |
| Stellar Radius | 1.7610 R☉ |
| Stellar Mass | 1.0810 M☉ |
| Bolometric Luminosity | 2.904 L☉ |
| Metallicity [Fe/H] | 0.070 dex |
| Stellar Age | 7.940 Gyr |
| Apparent Magnitude | V: 12.799 · G: 12.708 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.093000 AU |
| Orbital Period | 9.693 days |
| Mean Orbital Velocity | 104.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.3900° |
| Mean Bulk Density | 3.11 g/cm³ (17.2 km/s vesc) |
| Insolation Flux | 376.2100 S⊕ (~512,022 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2211.300 LY (677.975 pc) |