Kepler-543 b

Astrophysical Synthesis & Habitability Characterization

Kepler-543 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-543, located approximately 723.4 light-years (221.8 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.117% across the stellar disk), this world measures 2.5 Earth radii and has a measured mass of 6.8 Earth masses. Combining its mass and radius yields a mean bulk density of 2.4 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.09 g⊕ (10.69 m/s²), and an escape velocity of 18.4 km/s.

In its orbital architecture around Kepler-543, Kepler-543 b completes one full revolution every 13.9 Earth days at a semi-major axis of 0.1023 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 80.1 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 521 K (+248°C / +478°F) and receiving 23.08 S⊕ (~31,413 W/m²), Kepler-543 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-543 is classified as a stellar host with an effective photospheric temperature of 4,671 K, a radius of 0.67 R☉, a mass of 0.7 M☉, an estimated bolometric luminosity of 0.192 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.75 Gyr and a metallicity of [Fe/H] = -0.19 dex (metal-poor relative to the Sun). From Earth, Kepler-543 shines at apparent V-band magnitude 13.598 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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