Kepler-828 b
Astrophysical Synthesis & Habitability Characterization
Kepler-828 b is a confirmed super-earth exoplanet orbiting the star Kepler-828, located approximately 1876.4 light-years (575.32 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0323% across the stellar disk), this world measures 1.51 Earth radii and has a measured mass of 2.89 Earth masses. Combining its mass and radius yields a mean bulk density of 4.63 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.27 g⊕ (12.45 m/s²), and an escape velocity of 15.5 km/s.
In its orbital architecture around Kepler-828, Kepler-828 b completes one full revolution every 0.568 Earth days at a semi-major axis of 0.01228 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 235.3 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.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1848 K (+1575°C / +2867°F) and receiving 1,835.16 S⊕ (~2,497,651 W/m²), Kepler-828 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-828 is classified as a stellar host with an effective photospheric temperature of 5,039 K, a radius of 0.77 R☉, a mass of 0.81 M☉, an estimated bolometric luminosity of 0.343 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.57 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, Kepler-828 shines at apparent V-band magnitude 15.374 (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-828 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,039 K |
| Stellar Radius | 0.7700 R☉ |
| Stellar Mass | 0.8100 M☉ |
| Bolometric Luminosity | 0.343 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 4.570 Gyr |
| Apparent Magnitude | V: 15.374 · G: 15.044 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.012280 AU |
| Orbital Period | 0.568 days |
| Mean Orbital Velocity | 235.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.4900° |
| Mean Bulk Density | 4.63 g/cm³ (15.5 km/s vesc) |
| Insolation Flux | 1835.1590 S⊕ (~2,497,651 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1876.400 LY (575.322 pc) |