Kepler-157 b
Astrophysical Synthesis & Habitability Characterization
Kepler-157 b is a confirmed super-earth exoplanet orbiting the star Kepler-157, located approximately 2523.5 light-years (773.71 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0134% across the stellar disk), this world measures 1.32 Earth radii and has a measured mass of 2.3 Earth masses. Combining its mass and radius yields a mean bulk density of 5.51 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around Kepler-157, Kepler-157 b completes one full revolution every 1.732 Earth days at a semi-major axis of 0.028 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 175.8 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 1546 K (+1273°C / +2323°F) and receiving 1,572.31 S⊕ (~2,139,913 W/m²), Kepler-157 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-157 is classified as a stellar host with an effective photospheric temperature of 5,774 K, a radius of 1.044 R☉, a mass of 0.95 M☉, an estimated bolometric luminosity of 1.087 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.59 Gyr and a metallicity of [Fe/H] = -0.059 dex (near-solar heavy-element abundance). From Earth, Kepler-157 shines at apparent V-band magnitude 14.206 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-157 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-157 b sharing its stellar neighborhood alongside Kepler-157 d, Kepler-157 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-157 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,774 K |
| Stellar Radius | 1.0440 R☉ |
| Stellar Mass | 0.9500 M☉ |
| Bolometric Luminosity | 1.087 L☉ |
| Metallicity [Fe/H] | -0.059 dex |
| Stellar Age | 7.590 Gyr |
| Apparent Magnitude | V: 14.206 · G: 14.037 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.028000 AU |
| Orbital Period | 1.732 days |
| Mean Orbital Velocity | 175.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.2400° |
| Mean Bulk Density | 5.51 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 1572.3090 S⊕ (~2,139,913 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2523.500 LY (773.713 pc) |