Kepler-53 c
Astrophysical Synthesis & Habitability Characterization
Kepler-53 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-53, located approximately 4455.5 light-years (1366.07 parsecs) from the Solar System. First announced in 2012 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1066% across the stellar disk), this world measures 3.17 Earth radii (0.28 Jupiter radii) and has a measured mass of 36 Earth masses (0.11 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.23 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 3.58 g⊕ (35.11 m/s²), and an escape velocity of 37.7 km/s.
In its orbital architecture around Kepler-53, Kepler-53 c completes one full revolution every 38.558 Earth days at a semi-major axis of 0.22091 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 62.3 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 550 K (+277°C / +531°F) and receiving 23.18 S⊕ (~31,543 W/m²), Kepler-53 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-53 is classified as a stellar host with an effective photospheric temperature of 5,858 K, a radius of 0.89 R☉, a mass of 0.98 M☉, an estimated bolometric luminosity of 0.837 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.3 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-53 shines at apparent V-band magnitude 15.367 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-53 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-53 c sharing its stellar neighborhood alongside Kepler-53 d, Kepler-53 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-53 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,858 K |
| Stellar Radius | 0.8900 R☉ |
| Stellar Mass | 0.9800 M☉ |
| Bolometric Luminosity | 0.837 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 0.300 Gyr |
| Apparent Magnitude | V: 15.367 · G: 15.388 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.220910 AU |
| Orbital Period | 38.558 days |
| Mean Orbital Velocity | 62.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.9100° |
| Mean Bulk Density | 6.23 g/cm³ (37.7 km/s vesc) |
| Insolation Flux | 23.1760 S⊕ (~31,543 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4455.500 LY (1366.070 pc) |