Kepler-896 c
Astrophysical Synthesis & Habitability Characterization
Kepler-896 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-896, located approximately 7615.5 light-years (2334.93 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1293% across the stellar disk), this world measures 3.15 Earth radii (0.28 Jupiter radii) and has a measured mass of 10.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.78 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 20 km/s.
In its orbital architecture around Kepler-896, Kepler-896 c completes one full revolution every 29.542 Earth days at a semi-major axis of 0.1792 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 66 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 515 K (+242°C / +468°F) and receiving 16.56 S⊕ (~22,538 W/m²), Kepler-896 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-896 is classified as a stellar host with an effective photospheric temperature of 5,510 K, a radius of 0.803 R☉, a mass of 0.877 M☉, an estimated bolometric luminosity of 0.533 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.59 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, Kepler-896 shines at apparent V-band magnitude 15.457 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-896 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-896 c sharing its stellar neighborhood alongside Kepler-896 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-896 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,510 K |
| Stellar Radius | 0.8030 R☉ |
| Stellar Mass | 0.8770 M☉ |
| Bolometric Luminosity | 0.533 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | 7.590 Gyr |
| Apparent Magnitude | V: 15.457 · G: 15.431 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.179200 AU |
| Orbital Period | 29.542 days |
| Mean Orbital Velocity | 66 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 81.4400° |
| Mean Bulk Density | 1.78 g/cm³ (20 km/s vesc) |
| Insolation Flux | 16.5600 S⊕ (~22,538 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 7615.500 LY (2334.930 pc) |