Kepler-1896 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1896 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1896, located approximately 5652 light-years (1732.91 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0814% across the stellar disk), this world measures 3.099 Earth radii (0.28 Jupiter radii) and has a measured mass of 9.8 Earth masses. Combining its mass and radius yields a mean bulk density of 1.82 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 19.9 km/s.
In its orbital architecture around Kepler-1896, Kepler-1896 b completes one full revolution every 44.87 Earth days at a semi-major axis of 0.2529 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 61.3 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 536 K (+263°C / +505°F) and receiving 19.50 S⊕ (~26,540 W/m²), Kepler-1896 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1896 is classified as a stellar host with an effective photospheric temperature of 6,122 K, a radius of 0.996 R☉, a mass of 1.07 M☉, an estimated bolometric luminosity of 1.25 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, Kepler-1896 shines at apparent V-band magnitude 15.844 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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-1896 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,122 K |
| Stellar Radius | 0.9960 R☉ |
| Stellar Mass | 1.0700 M☉ |
| Bolometric Luminosity | 1.25 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 15.844 · G: 15.700 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.252900 AU |
| Orbital Period | 44.87 days |
| Mean Orbital Velocity | 61.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6700° |
| Mean Bulk Density | 1.82 g/cm³ (19.9 km/s vesc) |
| Insolation Flux | 19.5000 S⊕ (~26,540 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 5652.000 LY (1732.910 pc) |