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Question

Describe the three types of visible spectra that astronomers observe, and the conditions that produce each type of visible spectra.

Answer 1

Emission spectra - is the relative intensity of electromagnetic radiation of each frequency it emits when it is heated (or more generally when it is excited).

Absorption spectra - shows the fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies. An absorption spectrum is, in a sense, the opposite of an emission spectrum.

Refraction spectra - is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye.

Answer 2

Emission spectra

Absorption spectra

Refraction spectra