how do spectrographs help astronomers classify stars?\n○ they determine the size of stars.\n○ they evaluate…

how do spectrographs help astronomers classify stars?\n○ they determine the size of stars.\n○ they evaluate the color of stars.\n○ they measure the brightness of stars.\n○ they analyze the composition of stars.
Answer
Brief Explanations:
Spectrographs split starlight into spectra, where dark/bright lines correspond to specific elements present in the star. By analyzing these spectral lines, astronomers can identify the star's chemical composition, which is a key factor in stellar classification. Other options: size is determined via interferometry or eclipsing binaries, color via photometry, brightness via photometers.
Answer:
They analyze the composition of stars.