Kepler-152 c
Astrophysical Synthesis & Habitability Characterization
Kepler-152 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-152, located approximately 1438.6 light-years (441.09 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0916% across the stellar disk), this world measures 2.39 Earth radii and has a measured mass of 6.3 Earth masses. Combining its mass and radius yields a mean bulk density of 2.54 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 18.2 km/s.
In its orbital architecture around Kepler-152, Kepler-152 c completes one full revolution every 88.255 Earth days at a semi-major axis of 0.356 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 43.9 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.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.390 R⊕, Kepler-152 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star Kepler-152 is classified as a stellar host with an effective photospheric temperature of 5,088 K, a radius of 0.724 R☉, a mass of 0.779 M☉, an estimated bolometric luminosity of 0.315 L☉. Stellar evolution modeling indicates an estimated stellar age of 2 Gyr and a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, Kepler-152 shines at apparent V-band magnitude 14.379 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-152 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-152 c sharing its stellar neighborhood alongside Kepler-152 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-152 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,088 K |
| Stellar Radius | 0.7240 R☉ |
| Stellar Mass | 0.7790 M☉ |
| Bolometric Luminosity | 0.315 L☉ |
| Metallicity [Fe/H] | -0.120 dex |
| Stellar Age | 2.000 Gyr |
| Apparent Magnitude | V: 14.379 · G: 14.244 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.356000 AU |
| Orbital Period | 88.255 days |
| Mean Orbital Velocity | 43.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.3700° |
| Mean Bulk Density | 2.54 g/cm³ (18.2 km/s vesc) |
| Insolation Flux | 2.5700 S⊕ (~3,498 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1438.600 LY (441.090 pc) |