Kepler-875 b
Astrophysical Synthesis & Habitability Characterization
Kepler-875 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-875, located approximately 4052.9 light-years (1242.62 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0574% across the stellar disk), this world measures 2.9 Earth radii and has a measured mass of 8.75 Earth masses. Combining its mass and radius yields a mean bulk density of 1.98 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.4 km/s.
In its orbital architecture around Kepler-875, Kepler-875 b completes one full revolution every 27.507 Earth days at a semi-major axis of 0.1771 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 70 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 569 K (+296°C / +565°F) and receiving 41.43 S⊕ (~56,388 W/m²), Kepler-875 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-875 is classified as a stellar host with an effective photospheric temperature of 5,958 K, a radius of 1.11 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.393 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.39 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-875 shines at apparent V-band magnitude 15.357 (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-875 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,958 K |
| Stellar Radius | 1.1100 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 1.393 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 3.390 Gyr |
| Apparent Magnitude | V: 15.357 · G: 15.210 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.177100 AU |
| Orbital Period | 27.507 days |
| Mean Orbital Velocity | 70 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.7900° |
| Mean Bulk Density | 1.98 g/cm³ (19.4 km/s vesc) |
| Insolation Flux | 41.4310 S⊕ (~56,388 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4052.900 LY (1242.620 pc) |