Stellar astrophysics is the branch of astronomy that studies the properties, behavior, and evolution of stars. It focuses on understanding how stars form from clouds of gas and dust, how they generate energy through nuclear fusion, and how they evolve over time. Key concepts include the life cycles of stars, from their birth in nebulae to their eventual death as supernovae or white dwarfs. This field also examines the physical processes that govern stellar structures, such as temperature, luminosity, and mass. By studying different types of stars, including red giants and neutron stars, scientists can learn more about the universe's history and the fundamental laws of physics.