Kepler-841 b
Astrophysical Synthesis & Habitability Characterization
Kepler-841 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-841, located approximately 3258.2 light-years (998.96 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.3504% across the stellar disk), this world measures 5.23 Earth radii (0.47 Jupiter radii) and has a measured mass of 23.8 Earth masses. Combining its mass and radius yields a mean bulk density of 0.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.87 g⊕ (8.53 m/s²), and an escape velocity of 23.9 km/s.
In its orbital architecture around Kepler-841, Kepler-841 b completes one full revolution every 124.42 Earth days at a semi-major axis of 0.479 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 41.9 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 416 K (+143°C / +289°F) and receiving 1.65 S⊕ (~2,243 W/m²), Kepler-841 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-841 is classified as a stellar host with an effective photospheric temperature of 5,324 K, a radius of 0.81 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.473 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, Kepler-841 shines at apparent V-band magnitude 15.791 (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-841 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,324 K |
| Stellar Radius | 0.8100 R☉ |
| Stellar Mass | 0.8500 M☉ |
| Bolometric Luminosity | 0.473 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 4.470 Gyr |
| Apparent Magnitude | V: 15.791 · G: 15.744 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.479000 AU |
| Orbital Period | 124.42 days |
| Mean Orbital Velocity | 41.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 0.92 g/cm³ (23.9 km/s vesc) |
| Insolation Flux | 1.6480 S⊕ (~2,243 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3258.200 LY (998.961 pc) |