How do astronomers determine the chemical composition of stars?

• A. By analyzing the emission spectrum of light from the stars
• B. By observing the brightness of the stars
• C. By calculating the distance to the stars
• D. By measuring the temperature of the stars

Answer: (A)

Verified step by step guidance

1. Understand that the chemical composition of stars is determined by studying the light they emit or absorb.
2. Learn that when light from a star passes through a prism or diffraction grating, it splits into a spectrum of colors, which can show distinct lines called spectral lines.
3. Recognize that these spectral lines correspond to specific wavelengths of light absorbed or emitted by different elements, acting like fingerprints for each element.
4. Know that astronomers analyze these emission or absorption lines in the star's spectrum to identify which elements are present in the star's atmosphere.
5. Conclude that by comparing the observed spectral lines with known lines from elements on Earth, astronomers can determine the star's chemical composition.