hydrogen line

(redirected from Hydrogen Lines)

hydrogen line

(21 cm line) See H I region.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

hydrogen line

[′hī·drə·jən ‚līn]
(spectroscopy)
A spectral line emitted by neutral hydrogen having a frequency of 1420 megahertz and a wavelength of 21 centimeters; radiation from this line is used in radio astronomy to study the amount and velocity of hydrogen in the Galaxy.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
He covers the role of singular solutions of quantal equations in atomic physics, the classical description of crossings of energy terms and of charge exchange, classical stationary states, understanding the role of the singular spin-spin interaction in the binding energy of two-electron atoms/ions, the last observed line in the spectral series of hydrogen lines in magnetized plasma: s revision of the Inglis-Tellor concept, and extrema in transition energies resulting not in satellites but in dips within spectral lines.
287 (1919), Uber den Einfluh eines elektrischen Feldes auf die Feinstruktur der Wasserstofflinien) On the influence of an electric field on the fine structure of hydrogen lines), Zeitschrift fur Physik, 3: 199-223.
AM CVn stars differ from most other cataclysmic variables (CVs) in the lack of hydrogen lines from their spectra.
A minor objection to the use of Stark broadening to explain the width of the hydrogen lines in the gaseous models rests on the fact that the appropriate experiments on hydrogen plasma do not exist.
On August 8, 1872, he photographed Vega through a 28-inch Cassegrain telescope of his own design and manufacture, showing four prominent hydrogen lines. No one would match this achievement for four years, by which time Draper had photographed the spectra of several dozen more stars.
surface temperature (K) O Blue >25,000 B Blue 11,000-25,000 A Blue 7,500-11,000 F Blue to White 6,000-7,500 G White to Yellow 5,000-6,000 K Orange to Red 3,500-5,000 M Red <3,500 Type Main characteristics Examples O Singly ionised helium, strong ultraviolet continuum 10 Lacertae B Neutral helium lines in absorption Rigel, Spica A Hydrogen lines at maximum strength Sirius, Vega F Metallic lines become noticeable Canopus, Procyon G Solar-type spectra Sun, Capella K Metallic lines dominate.
A sampling of topics: the microstructure of a sunspot penumbra, penumbral moving magnetic features, SOLIS-VSM solar vector magnetograms, multigrid methods for polarized radiative transfer, tunable narrow-band filter for imaging polarimetry, the diffraction limited spectro-polarimeter, a brief overview of the Second Solar Spectrum, polarizability factors for molecular bands, spectro-polarimetry of cool stars, molecular diagnostics of the internal structure of starspots and sunspots, and the effect of turbulent electric fields on the scattering polarization of hydrogen lines. No subject index.
Any appliance must have its hydrogen lines cleaned and purged before charging a metal hydride vessel; if not, contamination of the cartridge is almost a certainty.
The hydrogen lines ofthe Balmer series, and, as Babcock has recently shown, ofthe Paschen series as well, are very strong in the Sun, though the energy required to put an atom into condition to absorb these series is, respectively, 10.16 and 12.04 volts-higher than for any other solar absorption lines.
Its already inconspicuous hydrogen lines became weaker, whereas lines from elements such as scandium, rubidium, yttrium, zirconium, barium, and tin started to appear.