How do astronomers use the pattern of absorption lines to determine the chemical composition of a star?

Answer

The pattern acts as a unique signature, or celestial fingerprint, for every element.

The position of the dark lines matches known elemental patterns, allowing astronomers to identify the specific atoms and ions present in the star's outer atmosphere.

How do astronomers use the pattern of absorption lines to determine the chemical composition of a star?

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What do spectra tell us about stars? - YouTube

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