Kepler-1822 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1822 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1822, located approximately 2927.6 light-years (897.6 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1196% across the stellar disk), this world measures 2.648 Earth radii and has a measured mass of 7.5 Earth masses. Combining its mass and radius yields a mean bulk density of 2.23 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.8 km/s.
In its orbital architecture around Kepler-1822, Kepler-1822 b completes one full revolution every 22.133 Earth days at a semi-major axis of 0.1416 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 69.6 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 507 K (+234°C / +453°F) and receiving 15.65 S⊕ (~21,300 W/m²), Kepler-1822 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1822 is classified as a stellar host with an effective photospheric temperature of 5,165 K, a radius of 0.702 R☉, a mass of 0.782 M☉, an estimated bolometric luminosity of 0.315 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.8 Gyr and a metallicity of [Fe/H] = -0.32 dex (metal-poor relative to the Sun). From Earth, Kepler-1822 shines at apparent V-band magnitude 15.804 (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-1822 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,165 K |
| Stellar Radius | 0.7020 R☉ |
| Stellar Mass | 0.7820 M☉ |
| Bolometric Luminosity | 0.315 L☉ |
| Metallicity [Fe/H] | -0.320 dex |
| Stellar Age | 0.800 Gyr |
| Apparent Magnitude | V: 15.804 · G: 15.569 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.141600 AU |
| Orbital Period | 22.133 days |
| Mean Orbital Velocity | 69.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9800° |
| Mean Bulk Density | 2.23 g/cm³ (18.8 km/s vesc) |
| Insolation Flux | 15.6500 S⊕ (~21,300 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2927.600 LY (897.597 pc) |