Each different kind of object provides astronomers with unique clues about the birth and evolution of stars, how galaxies form, what powers quasars, and what lies between the stars in our Milky Way galaxy. Stars are classified by astronomers based on their spectra, that is, how bright they appear at different wavelengths or colors. O stars have lines produced by helium prominent in their spectra. They appear whitish in color and have surface temperatures between 30,000 and 40,000 degrees. Stars are classified by astronomers based on their spectra, that is, how bright they appear at different wavelengths or colors.
B stars have lines produced by helium prominent in their spectra.
They appear bluish in color and have surface temperatures between 10,000 and 30,000 degrees. Stars are classified by astronomers based on their spectra, that is, how bright they appear at different wavelengths or colors. A stars have many lines from hydrogen in the spectra, and appear bluish-yellow in color. A stars have surface temperatures between 7,000 and 10,000 degrees. Stars are classified by astronomers based on their spectra, that is, how bright they appear at different wavelengths or colors.