Spectral classification is a method used by astronomers to categorize stars based on their light spectra. This classification system divides stars into different classes, primarily O, B, A, F, G, K, and M, which represent their temperature and color. Each class is further divided into subclasses, allowing for a more detailed understanding of a star's properties. The spectra of stars reveal important information about their composition, temperature, and luminosity. By analyzing the absorption lines in a star's spectrum, scientists can determine the presence of various elements and molecules, helping to uncover the star's age and evolutionary stage.