Kepler-896 b
Astrophysical Synthesis & Habitability Characterization
Kepler-896 b 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 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.082% across the stellar disk), this world measures 2.53 Earth radii and has a measured mass of 6.94 Earth masses. Combining its mass and radius yields a mean bulk density of 2.36 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.5 km/s.
In its orbital architecture around Kepler-896, Kepler-896 b completes one full revolution every 144.547 Earth days at a semi-major axis of 0.56378 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 42.4 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.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.530 R⊕, Kepler-896 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star Kepler-896 is classified as a stellar host with an effective photospheric temperature of 5,262 K, a radius of 0.81 R☉, a mass of 0.84 M☉, an estimated bolometric luminosity of 0.451 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.01 Gyr and a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). 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 b sharing its stellar neighborhood alongside Kepler-896 c.
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) | 5,262 K |
| Stellar Radius | 0.8100 R☉ |
| Stellar Mass | 0.8400 M☉ |
| Bolometric Luminosity | 0.451 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | 5.010 Gyr |
| Apparent Magnitude | V: 15.457 · G: 15.431 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.563780 AU |
| Orbital Period | 144.547 days |
| Mean Orbital Velocity | 42.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.5700° |
| Mean Bulk Density | 2.36 g/cm³ (18.5 km/s vesc) |
| Insolation Flux | 1.9900 S⊕ (~2,708 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 7615.500 LY (2334.930 pc) |