AST-091beginner

Emission, Absorption & Spectral Lines: Foundations

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: Foundations

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AST-090Blackbody Radiation: Advanced Connections→

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AST-092Emission, Absorption & Spectral Lines: Structures & Vocabulary→

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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.