Question

How can astronomers determine a star’s chemical composition?

Answer 1

The Stars are the huge celestial bodies that are made up mostly of hydrogen and helium and produce the light and the heat from the churning nuclear forges inside the cores.

Complete step by step answer:
The astronomers determine the chemical composition of stars, planets, and other objects by Spectroscopy. The process uses the instruments with a grating which spreads out the light from an object by the wavelength. The process of spread-out light is called a spectrum. Each element will have a unique fingerprint that can be looked at by the astronomers in the spectrum of the object. By identifying and analyzing these fingerprints, the astronomers can determine what it is made up of. The fingerprint appears to be the absorption of light.
Spectroscopy is the method used by astronomers to determine the chemical composition, mass and, also the temperature of the objects in the observable universe. They will take a spectrum of the object by using a spectrograph and is based on the principle that each element’s absorption lines are unique at a particular wavelength.
Thus the astronomers can measure the position of the lines and then determine which elements are present in the object. Even, the amount of light that is absorbed will also give information about how much of each element is present in it.

Note:
1. Constellation is the term that is used by astronomers to refer to an area of the sky.
2. Like human beings, stars also will be born and grow, become old and die.