emission line

Quick Reference

A bright line in a spectrum at a particular wavelength, given out by hot or excited atoms. Emission lines can appear superimposed on a normal absorption spectrum, as caused by hot gas around a star, or they can appear on their own, as in the spectrum of a nebula excited by radiation from a nearby hot star. They can be used to determine the temperature, pressure, and chemical composition of the emitting gas.

Subjects: Astronomy and Astrophysics.

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