Kepler-1638 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1638 b is a confirmed super-earth exoplanet orbiting the star Kepler-1638, located approximately 4975.6 light-years (1525.52 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0326% across the stellar disk), this world measures 1.87 Earth radii and has a measured mass of 4.16 Earth masses. Combining its mass and radius yields a mean bulk density of 3.51 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.19 g⊕ (11.67 m/s²), and an escape velocity of 16.7 km/s.
In its orbital architecture around Kepler-1638, Kepler-1638 b completes one full revolution every 259.337 Earth days at a semi-major axis of 0.745 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 31.3 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.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 304 K (+31°C / +88°F) and an incident stellar irradiance of 2.76 S⊕ (~3,756 W/m²), Kepler-1638 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-1638 is classified as a stellar host with an effective photospheric temperature of 5,710 K, a radius of 0.95 R☉, a mass of 0.97 M☉, an estimated bolometric luminosity of 0.861 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.37 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-1638 shines at apparent V-band magnitude 14.769 (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-1638 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,710 K |
| Stellar Radius | 0.9500 R☉ |
| Stellar Mass | 0.9700 M☉ |
| Bolometric Luminosity | 0.861 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 4.370 Gyr |
| Apparent Magnitude | V: 14.769 · G: 14.748 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.745000 AU |
| Orbital Period | 259.337 days |
| Mean Orbital Velocity | 31.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9954° |
| Mean Bulk Density | 3.51 g/cm³ (16.7 km/s vesc) |
| Insolation Flux | 2.7600 S⊕ (~3,756 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 4975.600 LY (1525.520 pc) |