Kepler-102 e
Astrophysical Synthesis & Habitability Characterization
Kepler-102 e is a confirmed sub-neptune exoplanet orbiting the star Kepler-102, located approximately 351.6 light-years (107.8 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0755% across the stellar disk), this world measures 2.17 Earth radii and has a measured mass of 4.7 Earth masses. Combining its mass and radius yields a mean bulk density of 2.54 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1 g⊕ (9.81 m/s²), and an escape velocity of 16.5 km/s.
In its orbital architecture around Kepler-102, Kepler-102 e completes one full revolution every 16.146 Earth days at a semi-major axis of 0.1162 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.089 carries the world between 0.1059 AU at periapsis and 0.1265 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 590 K (+317°C / +603°F) and receiving 20.30 S⊕ (~27,628 W/m²), Kepler-102 e orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-102 is classified as a stellar host with an effective photospheric temperature of 4,909 K, a radius of 0.724 R☉, a mass of 0.803 M☉, an estimated bolometric luminosity of 0.273 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.1 Gyr and a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, Kepler-102 shines at apparent V-band magnitude 12.072 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-102 system is a multi-planet architecture hosting 5 confirmed worlds, with Kepler-102 e sharing its stellar neighborhood alongside Kepler-102 b, Kepler-102 c, Kepler-102 d, Kepler-102 f.
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-102 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,909 K |
| Stellar Radius | 0.7240 R☉ |
| Stellar Mass | 0.8030 M☉ |
| Bolometric Luminosity | 0.273 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | 1.100 Gyr |
| Apparent Magnitude | V: 12.072 · G: 11.478 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.116200 AU |
| Orbital Period | 16.146 days |
| Mean Orbital Velocity | 78.3 km/s |
| Orbital Eccentricity (e) | 0.08900 |
| Orbital Inclination (i) | 89.4880° |
| Mean Bulk Density | 2.54 g/cm³ (16.5 km/s vesc) |
| Insolation Flux | 20.3000 S⊕ (~27,628 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 351.600 LY (107.796 pc) |