Each element, such as hydrogen and iron, has a set of gaps-wavelengths that it absorbs rather than radiates. So if those wavelengths are missing from the spectrum, you know that that element is present in the star you are observing.
Experts are waiting 24/7 to provide step-by-step solutions in as fast as 30 minutes!*
*Response times vary by subject and question complexity. Median response time is 34 minutes and may be longer for new subjects.