Which astronomer proposed the heliocentric model in his 1543 work De revolutionibus?

Nicolaus Copernicus proposed the heliocentric model in his 1543 work De revolutionibus orbium coelestium.

Copernicus argued that Earth rotates on its axis and travels around the Sun, rather than the Sun and planets revolving around a stationary Earth. His model challenged the dominant Ptolemaic system, which placed Earth at the center and used complex combinations of circles to explain planetary motion.

De revolutionibus was published in Nuremberg in 1543, the year Copernicus died. The book still retained some ancient assumptions, including circular planetary orbits, so it did not immediately provide the accuracy later achieved by Johannes Kepler's elliptical-orbit model. Galileo's telescopic observations subsequently supplied influential evidence for heliocentrism.

Copernicus did not invent the idea that the Sun could be central; ancient Greek thinkers had proposed related concepts. His achievement was developing and publishing a comprehensive mathematical heliocentric system in Renaissance Europe.