Spectral Type A stars are a category of stars characterized by their strong hydrogen lines in their spectra. They typically have surface temperatures ranging from about 7,500 to 10,000 Kelvin, giving them a bluish-white color. These stars are often more massive than the Sun and can be found in various stages of their life cycle, including main sequence stars and giants. Examples of Spectral Type A stars include Sirius A, the brightest star in the night sky, and Vega, a prominent star in the constellation Lyra. These stars are important for studying stellar evolution and the chemical composition of the universe.