The Essential Stellar Guide

by Angel Alguera, Gerald Davis, Brandon Jackson

How Do We Identify Elements In Stars?

To find out what a star is made out of, we will have to go into how the light spectrum works.


Every natural element has its own unique light spectrum pattern. In order to find out the light spectrum of a light source, scientists use a device called a spectroscope, a device that, when aligned correctly to the light source, separates the light into its respective colors. The colors are then reflected inside the spectroscope and spread out based on their wavelength. The resulting spectrum will be either a continuous, emission, or absorption spectrum.


Since stars emits light, scientists can use a spectroscope to find out the spectrum pattern of a star's light and find out what elements are present in a star.

How Is This Useful to Astronomers?

By knowing a star's elemental composition, scientists are able to find out more about how the star was made as well as the composition of planets orbiting it. The spectrum from the star can also reveal other important data such as its temperature, size, and motion.

Using the Sun as an Example

Since the Sun emits light like any other star in the universe, we can use a spectroscope to identify its elements.


When the light from the sun hits a spectroscope, the resulting spectrum will be an absorption spectrum, which looks like a continuous spectrum with black lines appearing.


Through this method, scientists have been able to find out the 3 most abundant elements of the Sun, which are:


  • Hydrogen (H, 73%)
  • Helium (He, 25%)
  • Carbon (C, 0.20%)

Examples of Spectrums