Results 201 to 210 of about 271,788 (231)

Molecular Abundances in Galaxies

AIP Conference Proceedings, 2006
Two topics are discussed here. The first is an observational study on molecular abundance in nearby (< 10 Mpc) gas‐rich galaxies based on our ammonia survey and on data in literature. As a result, a systematically peculiar molecular abundance was found in a famous starburst galaxy M 82 regarding the formation mechanisms of molecules.
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The evolution of abundances in the galaxy

AIP Conference Proceedings, 1989
This very brief review of the evolution of the abundances in our Galaxy first recalls the main observational facts regarding such abundances which have to be taken into account by any model of chemical evolution of our Galaxy. After having defined what are the crucial parameters which define such models, the emphasis is made on two approaches: the ...
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Nebulae and abundances in galaxies

Publications of the Astronomical Society of the Pacific, 1986
Some current problems related to abundances in H II regions are briefly reviewed. For H II regions with measured electron temperatures, the discrepancy in O/H between the sun and the Orion Nebula is stressed. Studies of abundance and temperature variations within H II regions in NGC 604 are summarized.
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Lithium abundance at the formation of the Galaxy

Nature, 1982
The observed abundance of lithium in population I stars (young stars)1 seems to have been stable during the past 5 × 109 yr (ref. 2). This stability has been used previously1,3 to estimate the abundance of lithium at the time of formation of the Galaxy and at pre-galactic times1,3. But because the basis for this estimate was not completely satisfactory,
M. Spite, F. Spite
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Chemical Abundances in Galaxies

1988
This article is intended as a brief overview of chemical abundances in galaxies other than our own. Attention is concentrated on global properties of ellipticals and spirals, and the methods by which abundances are estimated. References are predominantly to work which has appeared since the review of Pagel and Edmunds (1981).
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He abundances in disc galaxies

Astronomy & Astrophysics, 2019
We investigate how the stellar and gas-phase He abundances evolve as a function of time within simulated star-forming disc galaxies with different star formation histories. We make use of a cosmological chemodynamical simulation for galaxy formation and evolution, which includes star formation as well as energy and chemical enrichment feedback from ...
Vincenzo, F., Miglio, A., Kobayashi, C., Mackereth, J. T., Montalban, J.   +4 more
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3D gas-phase elemental abundances across the formation histories of Milky Way-mass galaxies in the FIRE simulations: initial conditions for chemical tagging

Monthly Notices of the Royal Astronomical Society, 2021
Xiangcheng Ma, Robert Feldmann, Claude-André Faucher-Giguère   +2 more
exaly  

Chemical Abundances and Galaxy Evolution

1984
The chemical abundance characteristics of two comparatively structurally simple classes of galaxies, the ellipticals and irregulars, are briefly reviewed. Neither of these types of galaxies have properties which are fully consistent with the quantitative predictions of basic chemical evolution models. Possible sources for discrepancies are discussed in
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Abundance Gradients in Spiral Galaxies

1997
The study of HII regions in the disks of spiral galaxies has given us important information about their physical conditions. In particular the study of their chemical abundances soon showed the existence of negative gradients with higher abundance towards the centre of a galaxy (e.g. Pagel and Edmunds 1981; McCall 1982; Diaz 1989; Dinerstein 1990).
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Chemical abundances in Seyfert galaxies – VI. Empirical abundance calibration

Monthly Notices of the Royal Astronomical Society, 2021
Oli Luiz Dors Junior
exaly