What classification system is used for stars based on their spectral characteristics?

The classification system used for stars based on their spectral characteristics is known as stellar classification. This system classifies stars primarily according to their temperature, which affects their color and spectral lines. The main spectral types are O, B, A, F, G, K, and M, arranged from the hottest to the coolest stars. Each class is further divided into subclasses using numbers, allowing for a detailed characterization of stellar properties.

This system is fundamental in astrophysics because it helps in understanding the physical processes occurring within stars, their lifecycle, and their evolution. In addition, spectral classification aids in determining other vital parameters such as luminosity and chemical composition, which are essential for studying the universe and its formation.

Other terms like stellar categorization, ranking, and designation are not standard in the scientific community for this specific classification system and do not encompass the rigorous methodology and detailed characteristics that stellar classification provides. Thus, stellar classification is the well-accepted and recognized term in the context of classifying stars based on their spectra.