The study of stars is called Astronomy. Astronomy is the study of everything in the universe. It is the study of the Sun, moon, stars, planets, comets, dust, gas, galaxies, and other non-earthly bodies. The main focus of astronomy is the observation of earthly bodies.
Astronomy is one of the oldest natural science, history has it in a record that astronomy was recorded by methodical observation of the night sky. Professionally, astronomy is split into observational and theoretical branches.
Observational astronomy is focused on gathering data from the observations of astronomical objects. While theoretical astronomy is based on the development of analytical or computer models to describe an astronomical object. Astronomy is broken down into subfields which include, planetary astronomers, solar astronomers, stellar astronomers, galactic astronomers and so on.