Kepler-82 b
Astrophysical Synthesis & Habitability Characterization
Kepler-82 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-82, located approximately 2949.5 light-years (904.33 parsecs) from the Solar System. First announced in 2012 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1727% across the stellar disk), this world measures 4.07 Earth radii (0.36 Jupiter radii) and has a measured mass of 12.15 Earth masses. Combining its mass and radius yields a mean bulk density of 0.99 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.73 g⊕ (7.16 m/s²), and an escape velocity of 19.3 km/s.
In its orbital architecture around Kepler-82, Kepler-82 b completes one full revolution every 26.44 Earth days at a semi-major axis of 0.1683 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 69.2 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0033 (ranging from 0.1677 AU at periapsis to 0.1689 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 562 K (+289°C / +552°F) and receiving 19.56 S⊕ (~26,618 W/m²), Kepler-82 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-82 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,401 K, a radius of 0.898 R☉, a mass of 0.91 M☉, an estimated bolometric luminosity of 0.616 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.41 Gyr and a metallicity of [Fe/H] = 0.211 dex (metal-rich relative to the Sun). From Earth, Kepler-82 shines at apparent V-band magnitude 15.131 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-82 system is a multi-planet architecture hosting 5 confirmed worlds, with Kepler-82 b sharing its stellar neighborhood alongside Kepler-82 d, Kepler-82 e, Kepler-82 c, Kepler-82 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-82 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,401 K |
| Stellar Radius | 0.8980 R☉ |
| Stellar Mass | 0.9100 M☉ |
| Bolometric Luminosity | 0.616 L☉ |
| Metallicity [Fe/H] | 0.211 dex |
| Stellar Age | 1.410 Gyr |
| Apparent Magnitude | V: 15.131 · G: 15.138 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.168300 AU |
| Orbital Period | 26.44 days |
| Mean Orbital Velocity | 69.2 km/s |
| Orbital Eccentricity (e) | 0.00330 |
| Orbital Inclination (i) | 89.0520° |
| Mean Bulk Density | 0.99 g/cm³ (19.3 km/s vesc) |
| Insolation Flux | 19.5580 S⊕ (~26,618 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2949.500 LY (904.326 pc) |