Results 51 to 60 of about 3,453 (176)
Cosmic Ray propagation in the interstellar medium
, 2014 International audienceThe transport of galactic cosmic rays from the sources to the Earth in the interstellar medium is an essential process for the understanding of several observations: abundances of secondary nuclei produced by spallation reactions ...
Marcowith, Alexandre
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The isotopic abundances of interstellar oxygen
The Astrophysical Journal, 1981 The relative abundance of /sup 17/O and /sup 18/O is found to be remarkably uniform in the giant molecular clouds of our Galaxy, varying by less than approx.5% between the galactic center and the most distant (approx.12 kpc) sources. This uniformity is seen to reflect the close similarity in the galactic distributions of the processes by which these ...
openaire +1 more source
The abundant elements in interstellar dust
The Astrophysical Journal, 1994 We explore the incorporation of the cosmically abundant species O, C, N, Mg, Si, Fe, and S into interstellar dust. Column densities based on Goddard High Resolution Spectrograph 3.5 km/s resolution measurements from the literature for eight individual absorbing regions toward five lines of sight are used.
Ulysses J. Sofia +2 more
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Helium and Hydrogen Abundances in the Heliosphere and the Local Interstellar Medium
, 2014 International audienceThe sun is generally thought to have the same helium abundance as that in the solar nebula from which it was formed 4.6 billion years ago. In contrast, the interstellar medium reflects current galactic conditions.
Vincent, Frédéric, Ben-Jaffel, Lotfi
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Meteorite Parent Body Aqueous Alteration Simulations of Interstellar Residue Analogs
, 2023 Some families of carbonaceous chondrites are rich in prebiotic organics that may have contributed to the origin of life on Earth and elsewhere. However, the formation and chemical evolution of complex soluble organic molecules from interstellar ...
José C. Aponte +11 more
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Interstellar Abundances in the Magellanic Clouds
, 2007 Introduction Studies of the interstellar medium (ISM) in the Magellanic Clouds (MC) offer the prospect of interesting comparisons both with the ISM in our own Galaxy and with the absorption-line systems (ALS) seen in the spectra of distant QSO's ...
Daniel Welty University
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, 2012 Context. Early B-type stars are ideal indicators for present-day cosmic abundances since they preserve their pristine abundances and typically do not migrate far beyond their birth environments over their short lifetimes, in contrast to older stars like ...
N. Przybilla +3 more
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Infrared Spectroscopy of Interstellar Dust
, 2009 IR spectroscopy is the premier tool to study the composition of interstellar dust. Broad absorption and emission bands provide direct identification of the solid compounds present in space and allow measurement of accurate abundances. Systematic studies
A.G.G.M. Tielens
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Interstellar abundances of oxygen and nitrogen
The Astrophysical Journal, 1983 Neutral nitrogen and oxygen column densities or limits are derived for 53 path lengths through the diffuse interstellar medium and compared with column densities of neutral hydrogen. For neither N nor O is a systematic increase of depletion found as reddening increases.
D. G. York +6 more
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First measurement of Mg isotope abundances at high redshifts and accurate estimate of Δα/α
, 2011 Aims. Abundances of the Mg isotopes Mg-24, Mg-25, and Mg-26 can be used to test models of chemical enrichment of interstellar/ intergalactic gas clouds.
J. L. Hou +7 more
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