Proxima Centauri b Proxima Centauri b Proxima Centauri b (also called Proxima b or Alpha Centauri Cb) is an exoplanet orbiting in the habitable zone of the red dwarf star Proxima Centauri, which is the closest star to the Sun and part of a triple star system. It is located about 4.2 light-years (1.3 parsecs, 40 trillion km, or 25 trillion miles) from Earth in the constellation of Centaurus, making it the closest known exoplanet to the Solar System. Proxima Centauri b orbits the star at a distance of roughly with an orbital period of approximately 11.2 Earth days, and has an estimated
Unit distance graph graph so that the edges are exactly the unit distance pairs, may greatly differ from each other: the 2"n"-vertex crown graph may be embedded in four dimensions so that all its edges have unit length, but requires at least "n" − 2 dimensions to be embedded so that the edges are the only unit-distance pairs . It is NP-hard, and more specifically complete for the existential theory of the reals, to test whether a given graph is a unit distance graph, or is a strict unit distance graph . It is also NP-complete to determine whether a unit distance graph