Kepler-822 b
Astrophysical Synthesis & Habitability Characterization
Kepler-822 b is a confirmed super-earth exoplanet orbiting the star Kepler-822, located approximately 2806.2 light-years (860.39 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0226% across the stellar disk), this world measures 1.77 Earth radii and has a measured mass of 3.78 Earth masses. Combining its mass and radius yields a mean bulk density of 3.76 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.21 g⊕ (11.87 m/s²), and an escape velocity of 16.3 km/s.
In its orbital architecture around Kepler-822, Kepler-822 b completes one full revolution every 3.223 Earth days at a semi-major axis of 0.04078 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 137.7 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 1239 K (+966°C / +1771°F) and receiving 535.19 S⊕ (~728,391 W/m²), Kepler-822 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-822 is classified as a stellar host with an effective photospheric temperature of 5,928 K, a radius of 1.08 R☉, a mass of 1.06 M☉, an estimated bolometric luminosity of 1.292 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-822 shines at apparent V-band magnitude 14.75 (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-822 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,928 K |
| Stellar Radius | 1.0800 R☉ |
| Stellar Mass | 1.0600 M☉ |
| Bolometric Luminosity | 1.292 L☉ |
| Metallicity [Fe/H] | 0.040 dex |
| Stellar Age | 3.550 Gyr |
| Apparent Magnitude | V: 14.750 · G: 14.597 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.040780 AU |
| Orbital Period | 3.223 days |
| Mean Orbital Velocity | 137.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.6700° |
| Mean Bulk Density | 3.76 g/cm³ (16.3 km/s vesc) |
| Insolation Flux | 535.1880 S⊕ (~728,391 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2806.200 LY (860.391 pc) |