Question

Why is bohr's model of the atom often called the planetary model

Answer 1

In the Bohr Model the neutrons and protons occupy a dense central region called a nucleus, and the electrons orbit the nucleus much like the planets orbiting the Sun (but the orbits are not confined to a plane as is approximately true in the Solar System).

Answer 2

its called planetary due to the fact that the electrons are arranged in circular orbits around the nucleus of the atom.