Kepler-153 c
Astrophysical Synthesis & Habitability Characterization
Kepler-153 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-153, located approximately 1498.3 light-years (459.37 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0676% across the stellar disk), this world measures 2.53 Earth radii and has a measured mass of 6.94 Earth masses. Combining its mass and radius yields a mean bulk density of 2.36 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.5 km/s.
In its orbital architecture around Kepler-153, Kepler-153 c completes one full revolution every 46.902 Earth days at a semi-major axis of 0.237 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 55 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 458 K (+185°C / +365°F) and receiving 6.42 S⊕ (~8,740 W/m²), Kepler-153 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-153 is classified as a stellar host with an effective photospheric temperature of 5,404 K, a radius of 0.892 R☉, a mass of 0.756 M☉, an estimated bolometric luminosity of 0.609 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.8 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, Kepler-153 shines at apparent V-band magnitude 14.388 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-153 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-153 c sharing its stellar neighborhood alongside Kepler-153 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-153 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,404 K |
| Stellar Radius | 0.8920 R☉ |
| Stellar Mass | 0.7560 M☉ |
| Bolometric Luminosity | 0.609 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 13.800 Gyr |
| Apparent Magnitude | V: 14.388 · G: 14.249 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.237000 AU |
| Orbital Period | 46.902 days |
| Mean Orbital Velocity | 55 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4900° |
| Mean Bulk Density | 2.36 g/cm³ (18.5 km/s vesc) |
| Insolation Flux | 6.4220 S⊕ (~8,740 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1498.300 LY (459.368 pc) |