What does the spectra of a star show?

The spectrum of a star reveals valuable information about its composition, temperature, density, and motion. By analyzing the absorption and emission lines in the spectrum, astronomers can identify the elements present in the star's atmosphere and their relative abundances. Additionally, the spectrum can indicate the star's temperature through the peak wavelength of emitted light, and any redshift or blueshift can provide insights into its velocity relative to Earth. Overall, a star's spectrum is a crucial tool for understanding its physical properties and behavior.