Kepler-240 c
Astrophysical Synthesis & Habitability Characterization
Kepler-240 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-240, located approximately 2436.1 light-years (746.93 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0745% across the stellar disk), this world measures 2.2 Earth radii and has a measured mass of 102.3 Earth masses (0.32 Jupiter masses). Combining its mass and radius yields a mean bulk density of 52.98 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 21.14 g⊕ (207.31 m/s²), and an escape velocity of 76.3 km/s.
In its orbital architecture around Kepler-240, Kepler-240 c completes one full revolution every 7.954 Earth days at a semi-major axis of 0.074 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 101.2 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 696 K (+423°C / +793°F) and receiving 59.84 S⊕ (~81,440 W/m²), Kepler-240 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-240 is classified as a stellar host with an effective photospheric temperature of 4,985 K, a radius of 0.739 R☉, a mass of 0.868 M☉, an estimated bolometric luminosity of 0.303 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.91 Gyr and a metallicity of [Fe/H] = 0.41 dex (metal-rich relative to the Sun). From Earth, Kepler-240 shines at apparent V-band magnitude 15.953 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-240 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-240 c sharing its stellar neighborhood alongside Kepler-240 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-240 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,985 K |
| Stellar Radius | 0.7390 R☉ |
| Stellar Mass | 0.8680 M☉ |
| Bolometric Luminosity | 0.303 L☉ |
| Metallicity [Fe/H] | 0.410 dex |
| Stellar Age | 1.910 Gyr |
| Apparent Magnitude | V: 15.953 · G: 15.662 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.074000 AU |
| Orbital Period | 7.954 days |
| Mean Orbital Velocity | 101.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2400° |
| Mean Bulk Density | 52.98 g/cm³ (76.3 km/s vesc) |
| Insolation Flux | 59.8380 S⊕ (~81,440 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2436.100 LY (746.927 pc) |