cosmic abundance

"Cosmic Abundance of Elements, using Solar System as Standard"click for a larger image
"Cosmic Abundance of Elements, using Solar System as Standard"

cosmic abundance

The relative proportion of each element found in the Universe. The standard cosmic abundance is based on that of the Solar System, determined from observations of the relative line strengths in the spectrum of solar radiation, from geological surveys of the Earth, and from analysis of meteorites (see table). The solar abundance in terms of numbers of atoms gives 90.8% hydrogen, 9.1% helium, and 0.1% other elements. Abundances deduced for most stars from their spectra usually agree quite well with the standard, although old stars tend to have rather less of the heavy elements (see population I, population II) and there are a number of odd stars with abundances quite unlike the rest. The abundances deduced from the absorption and emission lines of the interstellar medium do not agree so well, principally in that there is an apparent shortage of refractory elements such as iron. It is likely that these elements are present, however, but are bound up with the cosmic dust.

cosmic abundance

[′käz·mik ə′bən·dəns]
(astronomy)
The amount of a substance believed to be present in the entire universe, relative to other substances.
References in periodicals archive ?
This measurement is supremely important because from it, researchers can infer the cosmic abundance of baryons, which include the protons and neutrons that make up all atomic nuclei.
Even in its most primitive form, which does not include inflation, the Big Bang theory correctly predicts the cosmic abundance of helium and deuterium and the temperature of the radiation left over from the birth of the universe.
The researchers also report that their model can account for the cosmic abundance of hydrogen, helium, and deuterium.
5 to 100 -- matches the cosmic abundance predicted by the Big Bang theory.
Cosmic abundances as records of stellar evolution and nucleosynthesis in honor of David L.
Symposium on Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis.
Hogan of the University of Washington in Seattle points out that theories of how the first, light elements in the universe formed predict quite accurately the observed cosmic abundances of hydrogen, helium, and heavier elements.
Yet cosmic abundances do not always match the solar mixture.