Kepler-845 b
Astrophysical Synthesis & Habitability Characterization
Kepler-845 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-845, located approximately 1405.9 light-years (431.05 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0622% across the stellar disk), this world measures 2.04 Earth radii and has a measured mass of 4.82 Earth masses. Combining its mass and radius yields a mean bulk density of 3.13 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.16 g⊕ (11.38 m/s²), and an escape velocity of 17.2 km/s.
In its orbital architecture around Kepler-845, Kepler-845 b completes one full revolution every 0.928 Earth days at a semi-major axis of 0.01668 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 195.6 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 1361 K (+1088°C / +1990°F) and receiving 772.50 S⊕ (~1,051,370 W/m²), Kepler-845 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-845 is classified as a stellar host with an effective photospheric temperature of 4,913 K, a radius of 0.75 R☉, a mass of 0.79 M☉, an estimated bolometric luminosity of 0.294 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.79 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-845 shines at apparent V-band magnitude 14.903 (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-845 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,913 K |
| Stellar Radius | 0.7500 R☉ |
| Stellar Mass | 0.7900 M☉ |
| Bolometric Luminosity | 0.294 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 4.790 Gyr |
| Apparent Magnitude | V: 14.903 · G: 14.639 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.016680 AU |
| Orbital Period | 0.928 days |
| Mean Orbital Velocity | 195.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 76.1500° |
| Mean Bulk Density | 3.13 g/cm³ (17.2 km/s vesc) |
| Insolation Flux | 772.4980 S⊕ (~1,051,370 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1405.900 LY (431.051 pc) |