Kepler-1543 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1543 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1543, located approximately 3006.5 light-years (921.78 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0227% across the stellar disk), this world measures 2.71 Earth radii and has a measured mass of 7.8 Earth masses. Combining its mass and radius yields a mean bulk density of 2.16 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 19 km/s.

In its orbital architecture around Kepler-1543, Kepler-1543 b completes one full revolution every 6.967 Earth days at a semi-major axis of 0.0867 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 135.4 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 1774 K (+1501°C / +2734°F) and receiving 375.65 S⊕ (~511,261 W/m²), Kepler-1543 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1543 is classified as a stellar host with an effective photospheric temperature of 6,561 K, a radius of 1.65 R☉, a mass of 1.39 M☉, an estimated bolometric luminosity of 4.526 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.91 Gyr and a metallicity of [Fe/H] = 0.07 dex (metal-rich relative to the Sun). From Earth, Kepler-1543 shines at apparent V-band magnitude 13.495 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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