Emission line stars

Emission line stars are a type of star that emits specific wavelengths of light, leading to bright lines—called emission lines—in their spectrum. This occurs when certain elements in the star’s atmosphere absorb energy and re-emit it, typically in the form of light. These stars are often young and hot, featuring strong stellar winds. Common examples include giant and supergiant stars, where significant energy and activity result in these distinctive spectral lines. Studying emission line stars helps astronomers understand stellar evolution and the chemical composition of the universe.