Composition of Stars
To learn what stars are made of, astronomers study the light from stars. When you look at white light through
a glass prism, you see a rainbow of colors called a spectrum (plural, spectra). The spectrum consists of millions of colors, including red, orange, yellow, green, blue, and violet. Astronomers use an instrument called a spectroscope to separate a star’s light into a spectrum. The spectrum gives astronomers information about the composition and temperature of a star.
Types of Spectra
A hot, solid object, such as the glowing wire inside a light bulb, gives off a continuous spectrum. A continuous spectrum shows all of the colors. However, hot gases emit only certain wavelengths of light, or colors. When a chemical element emits light, only some colors in the spectrum show up. All of the other colors are missing. The colors that appear are called emission lines. Every element has a unique set of bright emission lines that act like a fingerprint for that element.
Types of Stars
