Final answer:
Scientists use spectroscopic analysis to figure out the composition of a star's outer layer by analyzing its spectrum. This provides information about the star's temperature, chemical composition, atmospheric pressure, and motion. By understanding the chemical makeup of stars, astronomers can form theories about their evolution.
Step-by-step explanation:
Scientists use different spectra to figure out the composition of a star's outer layer through spectroscopic analysis. By analyzing the spectrum of a star, astronomers can measure its temperature, chemical composition, atmospheric pressure, and motion.
The spectrum of a star contains clear information about the chemical makeup of the star, allowing scientists to understand what the star is made of and how it evolved.