Kepler-656 c
Astrophysical Synthesis & Habitability Characterization
Kepler-656 c is a confirmed super-earth exoplanet orbiting the star Kepler-656, located approximately 2903.9 light-years (890.35 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0184% across the stellar disk), this world measures 1.41 Earth radii and has a measured mass of 2.57 Earth masses. Combining its mass and radius yields a mean bulk density of 5.06 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.29 g⊕ (12.65 m/s²), and an escape velocity of 15.1 km/s.
In its orbital architecture around Kepler-656, Kepler-656 c completes one full revolution every 5.254 Earth days at a semi-major axis of 0.0602 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 124.6 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 975 K (+702°C / +1296°F) and receiving 213.25 S⊕ (~290,233 W/m²), Kepler-656 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-656 is classified as a stellar host with an effective photospheric temperature of 5,550 K, a radius of 0.954 R☉, a mass of 1.05 M☉, an estimated bolometric luminosity of 0.775 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.4 Gyr and a metallicity of [Fe/H] = 0.46 dex (metal-rich relative to the Sun). From Earth, Kepler-656 shines at apparent V-band magnitude 15.549 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-656 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-656 c sharing its stellar neighborhood alongside Kepler-656 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-656 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,550 K |
| Stellar Radius | 0.9540 R☉ |
| Stellar Mass | 1.0500 M☉ |
| Bolometric Luminosity | 0.775 L☉ |
| Metallicity [Fe/H] | 0.460 dex |
| Stellar Age | 2.400 Gyr |
| Apparent Magnitude | V: 15.549 · G: 15.337 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.060200 AU |
| Orbital Period | 5.254 days |
| Mean Orbital Velocity | 124.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 83.6100° |
| Mean Bulk Density | 5.06 g/cm³ (15.1 km/s vesc) |
| Insolation Flux | 213.2500 S⊕ (~290,233 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2903.900 LY (890.352 pc) |