Be stars are a type of massive star that are characterized by their high luminosity and temperature. They are typically found in the main sequence phase of stellar evolution and are much larger than our Sun. These stars burn their nuclear fuel at a rapid rate, leading to a short lifespan compared to smaller stars. The classification of Be stars is based on their spectral characteristics, which show strong emission lines of hydrogen and other elements. This emission is often due to a surrounding disk of gas and dust, which can be ejected from the star itself. Be stars are important for studying stellar evolution and the dynamics of stellar environments.