Kepler16

Kepler-16 is a binary star system in the constellation Cygnus, located about 200 light-years from Earth. The system consists of Kepler-16A, a K-type main-sequence star, and Kepler-16B, an M-type red dwarf. The two stars orbit each other with a period of about 41 days and are separated by roughly 0.2–0.3 astronomical units, producing a distinctive double-sunset appearance from certain vantage points.

In 2011, the Kepler space telescope detected transits that revealed a planet orbiting the binary, designated Kepler-16b. It was the first confirmed planet to reside in a circumbinary orbit, meaning it circles around both stars. The discovery demonstrated that planets can form and maintain stable orbits in binary-star systems, expanding the known diversity of planetary systems.

Kepler-16b is a gas giant with a mass similar to Saturn and a radius comparable to Jupiter. It completes an orbit around the binary roughly every 229 days, at a distance of about 0.6 astronomical units from the barycenter. The arrangement provides a dynamic environment in which the planet experiences varying illumination from the two stars, influencing its climate and potential observable characteristics.

The Kepler-16 system is frequently cited as the archetype of circumbinary planets and is informally nicknamed the “Tatooine” planet in popular culture. As a landmark discovery, it has informed subsequent studies of planet formation, orbital dynamics, and transit photometry in systems with multiple stars.