Fraunhofer lines

American  

plural noun

Astronomy.

1. the dark lines of the solar spectrum.

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Fraunhofer lines British  

/ ˈfraunhoːfər /

plural noun

1. a set of dark lines appearing in the continuous emission spectrum of the sun. It is caused by the absorption of light of certain wavelengths coming from the hotter region of the sun by elements in the cooler outer atmosphere

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Etymology

Origin of Fraunhofer lines

First recorded in 1830–40; named after J. von Fraunhofer

Example Sentences

The real existence of this atmosphere, which is totally distinct from the beds of ignited vapours producing the Fraunhofer lines, is not open to doubt, although its nature is still a matter of conjecture.

From A Popular History of Astronomy During the Nineteenth Century Fourth Edition by Clerke, Agnes M. (Agnes Mary)

In astronomical and astrophysical matter italicize: The lower-case letters designating certain Fraunhofer lines: a, b, g, h.

From The Uses of Italic A Primer of Information Regarding the Origin and Uses of Italic Letters by Hamilton, Frederick W. (Frederick William)

This first discovery was quickly followed up by the identification of numerous bright rays in the spectra of other metallic bodies with others of the hitherto mysterious Fraunhofer lines.

From A Popular History of Astronomy During the Nineteenth Century Fourth Edition by Clerke, Agnes M. (Agnes Mary)

Proceed to focus by sliding the outer tube to and fro until the colors are quite clear and distinct, and at same time screw down the slit until the Fraunhofer lines appear.

From Scientific American Supplement, No. 821, September 26, 1891 by Various

This photograph completely confirms Young’s discovery, and shows the prominent Fraunhofer lines bright, the bright lines of the chromosphere spectrum being especially conspicuous.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" by Various