Fraunhofer lines

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Fraun·ho·fer lines

 (froun′hō′fər)
pl.n.
A set of several hundred dark lines appearing against the bright background of the continuous solar spectrum and produced by absorption of light by the cooler gases in the sun's outer atmosphere at frequencies corresponding to the atomic transition frequencies of these gases.

[After Joseph von Fraunhofer (1787-1826), German physicist.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Fraunhofer lines

(German ˈfraunhoːfər)
pl n
(Anatomy) 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
[named after J. von Fraunhofer (1787–1826), German physicist]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

Fraunhofer lines

Dark lines seen on the Sun and other stars, named after their 1814 Bavarian discoverer.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
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References in periodicals archive ?
It achieves this by checking its laser frequency against spectral absorption lines of an internal gas cell.
Once calibrated, the elements represented by the dips in the graph (the absorption lines caused by elements in the star's atmosphere) are easy to determine.
Normal stellar explosions emit light with special spectral signs or absorption lines produced by certain elements that absorb the wavelength.
"Linares and collaborators circumvent this problem by using high-quality optical spectra from the Gran Telescopio Canarias and other telescopes to identify, for the first time, absorption lines from both the cool side and the hot side of the companion star.
Based on the width of the absorption lines and the intensity, the total pressure and the CO2 concentration in the package is determined.
While competitive laser-based instruments operate in the near-infrared range, the Delta Ray platform was designed to operate in the mid-infrared range because absorption lines are about 8,000 times stronger than the NIR.
The number of emission lines increased significantly, while most absorption lines detected earlier became weaker or disappeared.
Their presence has been revealed through the detection of hydrogen absorption lines in the spectra of distant quasars.
For a given reference cell of length [L.sub.ref] the dynamic length range [r.sub.L,max] that can be covered can be remarkably exceeded if one probes two different absorption lines, giving rise to the modified expression [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], thus considering different individual line strengths [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] for two different lines of the same gas probed in the two cells.
[sup.57]Fe Mossbauer spectra of polycrystals of (I) and (II) are a single doublets; with the parameters (quadrupole splitting [delta][E.sub.Q] = 0.913(4) mm/s, isomer shift [[delta].sub.Fe] = 0.085(2) mm/s, width of absorption lines 0.272(1) mm/s for (I) and [delta][E.sub.Q] = 1.009(3) mm/s, dFe = 0.076(2) mm/s, width of absorption lines 0.250(1) mm/s for (II) at temperature 85 K).