Kepler-1957 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1957 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1957, located approximately 1503.2 light-years (460.9 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0126% across the stellar disk), this world measures 0.944 Earth radii and has a measured mass of 0.79 Earth masses. Combining its mass and radius yields a mean bulk density of 5.18 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.89 g⊕ (8.73 m/s²), and an escape velocity of 10.2 km/s.

In its orbital architecture around Kepler-1957, Kepler-1957 b completes one full revolution every 2.187 Earth days at a semi-major axis of 0.0299 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 148.8 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 1099 K (+826°C / +1519°F) and receiving 345.07 S⊕ (~469,640 W/m²), Kepler-1957 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1957 is classified as a stellar host with an effective photospheric temperature of 4,904 K, a radius of 0.772 R☉, a mass of 0.745 M☉, an estimated bolometric luminosity of 0.309 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-1957 shines at apparent V-band magnitude 15.13 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).