Kepler-152 b
Astrophysical Synthesis & Habitability Characterization
Kepler-152 b 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 0.1248% across the stellar disk), this world measures 2.79 Earth radii and has a measured mass of 8.2 Earth masses. Combining its mass and radius yields a mean bulk density of 2.08 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 19.2 km/s.
In its orbital architecture around Kepler-152, Kepler-152 b completes one full revolution every 18.208 Earth days at a semi-major axis of 0.124 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 74.1 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 551 K (+278°C / +532°F) and receiving 21.08 S⊕ (~28,695 W/m²), Kepler-152 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
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 b sharing its stellar neighborhood alongside Kepler-152 c.
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) | 0.124000 AU |
| Orbital Period | 18.208 days |
| Mean Orbital Velocity | 74.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.7700° |
| Mean Bulk Density | 2.08 g/cm³ (19.2 km/s vesc) |
| Insolation Flux | 21.0840 S⊕ (~28,695 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1438.600 LY (441.090 pc) |