Kepler-1635 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1635 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1635, located approximately 3488.1 light-years (1069.45 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1541% across the stellar disk), this world measures 3.64 Earth radii (0.32 Jupiter radii) and has a measured mass of 12.9 Earth masses. Combining its mass and radius yields a mean bulk density of 1.47 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.97 g⊕ (9.51 m/s²), and an escape velocity of 21.1 km/s.
In its orbital architecture around Kepler-1635, Kepler-1635 b completes one full revolution every 469.631 Earth days (1.29Julian years) at a semi-major axis of 1.12664 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 26.1 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.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 3.640 R⊕, Kepler-1635 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-1635 is classified as a stellar host with an effective photospheric temperature of 5,347 K, a radius of 0.85 R☉, a mass of 0.89 M☉, an estimated bolometric luminosity of 0.53 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.9 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1635 shines at apparent V-band magnitude 15.82 (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-1635 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,347 K |
| Stellar Radius | 0.8500 R☉ |
| Stellar Mass | 0.8900 M☉ |
| Bolometric Luminosity | 0.53 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 4.900 Gyr |
| Apparent Magnitude | V: 15.820 · G: 15.693 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.126640 AU |
| Orbital Period | 469.631 days |
| Mean Orbital Velocity | 26.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6100° |
| Mean Bulk Density | 1.47 g/cm³ (21.1 km/s vesc) |
| Insolation Flux | 0.4000 S⊕ (~544 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3488.100 LY (1069.450 pc) |