Kepler-864 b
Astrophysical Synthesis & Habitability Characterization
Kepler-864 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-864, located approximately 6597.8 light-years (2022.9 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0484% across the stellar disk), this world measures 2.4 Earth radii and has a measured mass of 6.35 Earth masses. Combining its mass and radius yields a mean bulk density of 2.53 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 18.2 km/s.
In its orbital architecture around Kepler-864, Kepler-864 b completes one full revolution every 5.834 Earth days at a semi-major axis of 0.0687 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 128.1 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 1143 K (+870°C / +1598°F) and receiving 464.77 S⊕ (~632,545 W/m²), Kepler-864 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-864 is classified as a stellar host with an effective photospheric temperature of 5,754 K, a radius of 1 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 0.983 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.68 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-864 shines at apparent V-band magnitude 15.898 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-864 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-864 b sharing its stellar neighborhood alongside Kepler-864 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-864 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,754 K |
| Stellar Radius | 1.0000 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 0.983 L☉ |
| Metallicity [Fe/H] | 0.040 dex |
| Stellar Age | 4.680 Gyr |
| Apparent Magnitude | V: 15.898 · G: 15.782 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.068700 AU |
| Orbital Period | 5.834 days |
| Mean Orbital Velocity | 128.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 84.6000° |
| Mean Bulk Density | 2.53 g/cm³ (18.2 km/s vesc) |
| Insolation Flux | 464.7650 S⊕ (~632,545 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 6597.800 LY (2022.900 pc) |