Kepler-442 b
Astrophysical Synthesis & Habitability Characterization
Kepler-442 b is a confirmed super-earth exoplanet orbiting the star Kepler-442, located approximately 1193.6 light-years (365.97 parsecs) from the Solar System. First announced in 2015 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0422% across the stellar disk), this world measures 1.34 Earth radii and has a measured mass of 2.36 Earth masses. Combining its mass and radius yields a mean bulk density of 5.41 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.31 g⊕ (12.85 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around Kepler-442, Kepler-442 b completes one full revolution every 112.305 Earth days at a semi-major axis of 0.409 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 39.6 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.04 (ranging from 0.3926 AU at periapsis to 0.4254 AU at apoapsis), the planet experiences minimal orbital distance variation.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 241 K (-32°C / -26°F) and an incident stellar irradiance of 0.66 S⊕ (~898 W/m²), Kepler-442 b orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
The host star Kepler-442 is classified as a stellar host with an effective photospheric temperature of 4,402 K, a radius of 0.598 R☉, a mass of 0.609 M☉, an estimated bolometric luminosity of 0.12 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.9 Gyr and a metallicity of [Fe/H] = -0.37 dex (metal-poor relative to the Sun). From Earth, Kepler-442 shines at apparent V-band magnitude 15.322 (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-442 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,402 K |
| Stellar Radius | 0.5980 R☉ |
| Stellar Mass | 0.6090 M☉ |
| Bolometric Luminosity | 0.12 L☉ |
| Metallicity [Fe/H] | -0.370 dex |
| Stellar Age | 2.900 Gyr |
| Apparent Magnitude | V: 15.322 · G: 14.930 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.409000 AU |
| Orbital Period | 112.305 days |
| Mean Orbital Velocity | 39.6 km/s |
| Orbital Eccentricity (e) | 0.04000 |
| Orbital Inclination (i) | 89.9400° |
| Mean Bulk Density | 5.41 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 0.6600 S⊕ (~898 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 1193.600 LY (365.965 pc) |