Kepler-825 c
Astrophysical Synthesis & Habitability Characterization
Kepler-825 c is a confirmed super-earth exoplanet orbiting the star Kepler-825, located approximately 2634.9 light-years (807.85 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0244% across the stellar disk), this world measures 1.84 Earth radii and has a measured mass of 4.04 Earth masses. Combining its mass and radius yields a mean bulk density of 3.58 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 16.6 km/s.
In its orbital architecture around Kepler-825, Kepler-825 c completes one full revolution every 8.182 Earth days at a semi-major axis of 0.0759 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 100.9 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 981 K (+708°C / +1306°F) and receiving 261.63 S⊕ (~356,076 W/m²), Kepler-825 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-825 is classified as a stellar host with an effective photospheric temperature of 5,976 K, a radius of 1.08 R☉, a mass of 1.03 M☉, an estimated bolometric luminosity of 1.335 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = -0.08 dex (near-solar heavy-element abundance). From Earth, Kepler-825 shines at apparent V-band magnitude 14.296 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-825 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-825 c sharing its stellar neighborhood alongside Kepler-825 b.
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-825 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,976 K |
| Stellar Radius | 1.0800 R☉ |
| Stellar Mass | 1.0300 M☉ |
| Bolometric Luminosity | 1.335 L☉ |
| Metallicity [Fe/H] | -0.080 dex |
| Stellar Age | 3.550 Gyr |
| Apparent Magnitude | V: 14.296 · G: 14.145 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.075900 AU |
| Orbital Period | 8.182 days |
| Mean Orbital Velocity | 100.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.1100° |
| Mean Bulk Density | 3.58 g/cm³ (16.6 km/s vesc) |
| Insolation Flux | 261.6280 S⊕ (~356,076 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2634.900 LY (807.850 pc) |