Kepler-443 b
Astrophysical Synthesis & Habitability Characterization
Kepler-443 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-443, located approximately 2616.7 light-years (802.27 parsecs) from the Solar System. First announced in 2015 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0915% across the stellar disk), this world measures 2.33 Earth radii and has a measured mass of 6.04 Earth masses. Combining its mass and radius yields a mean bulk density of 2.63 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 18 km/s.
In its orbital architecture around Kepler-443, Kepler-443 b completes one full revolution every 177.669 Earth days at a semi-major axis of 0.495 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 30.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.11 carries the world between 0.4406 AU at periapsis and 0.5495 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.330 R⊕, Kepler-443 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star Kepler-443 is classified as a stellar host with an effective photospheric temperature of 4,723 K, a radius of 0.706 R☉, a mass of 0.738 M☉, an estimated bolometric luminosity of 0.223 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-443 shines at apparent V-band magnitude 16.207 (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-443 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,723 K |
| Stellar Radius | 0.7060 R☉ |
| Stellar Mass | 0.7380 M☉ |
| Bolometric Luminosity | 0.223 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 16.207 · G: 15.901 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.495000 AU |
| Orbital Period | 177.669 days |
| Mean Orbital Velocity | 30.3 km/s |
| Orbital Eccentricity (e) | 0.11000 |
| Orbital Inclination (i) | 89.9400° |
| Mean Bulk Density | 2.63 g/cm³ (18 km/s vesc) |
| Insolation Flux | 0.8600 S⊕ (~1,170 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2616.700 LY (802.271 pc) |