hydrogen line


Also found in: Wikipedia.

hydrogen line

(21 cm line) See H I region.

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.
References in periodicals archive ?
Under the circumstances, hydrogen line shapes may be providing important clues with respect to the interaction between molecular hydrogen and larger condensed structures in the chromosphere.
Using the FUNcube Dongle and budget alternatives for hydrogen line reception
In the meantime Laurence Newell has offered to use the Spectracyber hydrogen line receiver purchased for this project with one of his own dishes to provide data for the website.
Frequencies around the hydrogen line are supposed to be protected for radio astronomy, so terrestrial interference is less severe than elsewhere across the radio spectrum.
05-hertz channels near the supposed "magic" frequency of the 21-centimeter hydrogen line and its second harmonic, at 1.
A low-noise amplifier for the 21-cm hydrogen line may be built or purchased for about $100.
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.
AM CVn stars differ from most other cataclysmic variables (CVs) in the lack of hydrogen lines from their spectra.
On August 8, 1872, he photographed Vega through a 28-inch Cassegrain telescope of his own design and manufacture, showing four prominent hydrogen lines.
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.
Tenders are invited for globe valves for hydrogen lines
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.