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The Fraunhofer lines are a set of dark lines in the spectrum of sunlight that result from the absorption of specific wavelengths by elements in the Sun’s atmosphere. In the 19th century, during the analysis of these spectral lines, a unique set of spectral lines was observed that could not be attributed to any known elements on Earth. This led to the discovery of helium in 1868, long before it was found on Earth. Therefore, the element discovered through the study of Fraunhofer lines is Helium.