AST-092beginner

Emission, Absorption & Spectral Lines: Structures & Vocabulary

Spectral lines are narrow wavelength features produced when atoms, ions, or molecules exchange energy in quantized transitions. Spectroscopy lets astronomers determine what distant objects are made of without sampling them physically and provides some of the most precise measurements of radial velocity.

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Emission, Absorption & Spectral Lines: Structures & Vocabulary

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AST-091Emission, Absorption & Spectral Lines: Foundations→

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AST-093Emission, Absorption & Spectral Lines: Physical Mechanisms→

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Spectral lines are narrow wavelength features produced when atoms, ions, or molecules exchange energy in quantized transitions.

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An electron or molecule absorbs a photon when the photon energy matches an allowed upward transition.

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Laboratory spectra identify the rest wavelengths of elements and molecules.