Results 11 to 20 of about 612,500 (304)

Light Elements in the Universe

Frontiers in Astronomy and Space Sciences, 2021
Due to their production sites, as well as to how they are processed and destroyed in stars, the light elements are excellent tools to investigate a number of crucial issues in modern astrophysics: from stellar structure and non-standard processes at work
Sofia Randich, Laura Magrini
doaj   +1 more source

Non-LTE Abundances of Magnesium, Aluminum and Sulfur in OB Stars Near the Solar Circle [PDF]

, 2002
Non-LTE abundances of magnesium, aluminum and sulfur are derived for a sample of 23 low-v \sin i stars belonging to six northern OB associations of the Galactic disk within 1 kpc of the Sun.
Afflerbach, Andrievsky, Daflon, Daflon, Daflon, Deharveng, Dufton, Gies, Grevesse, Gummersbach, Heger, K. Butler, K. Cunha, McNamara, Mihalas, Przybilla, S. Daflon, Simpson, V. V. Smith, Vrancken, Vrancken, Vrancken   +21 more
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MANGANESE ABUNDANCES IN THE ATMOSPHERE OF CLUMP GIANTS

Odessa Astronomical Publications, 2013
The manganese abundances was determined in the atmospheres of clump giants stars whose election was made earlier based on their chemical composition and evolutionary tracks. The spectra of the studied stars were obtained using the facilities of the 1.93m
T. I. Gorbaneva
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Indirect Measurements of n- and p-Induced Reactions of Astrophysical Interest on Oxygen Isotopes

Frontiers in Astronomy and Space Sciences, 2020
Observations of abundances and isotopic ratio determinations in stars yield powerful constraints on stellar models. In particular, the oxygen isotopic ratios are of particular interest because they are affected not only by nucleosynthesis but also by ...
M. L. Sergi, M. L. Sergi, G. L. Guardo, G. L. Guardo, M. La Cognata, M. Gulino, M. Gulino, J. Mrazek, S. Palmerini, S. Palmerini, C. Spitaleri, C. Spitaleri, M. Wiescher   +12 more
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Structure formation cosmic rays: Identifying observational constraints [PDF]

Serbian Astronomical Journal, 2005
Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs) would essentially be primordial in composition, namely, mostly made of ...
Prodanović T., Fields B.D.
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Neon and Sulfur Abundances of Planetary Nebulae in the Magellanic Clouds [PDF]

, 2007
The chemical abundances of neon and sulfur for 25 planetary nebulae (PNe) in the Magellanic Clouds are presented. These abundances have been derived using mainly infrared data from the Spitzer Space Telescope.
Aller L. H., de Graauw T., Feldman U., Fluks M. A., Grevesse N., J. Bernard‐Salas, J. R. Houck, Monk D. J., P. W. Morris, Pena M., S. Gutenkunst, S. R. Pottasch, Zijlstra A. A.   +12 more
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Close Binaries and the Abundance Discrepancy Problem in Planetary Nebulae

Galaxies, 2018
Motivated by the recent establishment of a connection between central star binarity and extreme abundance discrepancies in planetary nebulae, we have carried out a spectroscopic survey targeting planetary nebula with binary central stars and previously ...
R. Wesson, D. Jones, J. García-Rojas, H. M. J. Boffin, R. L. M. Corradi   +4 more
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Calcareous Nannofossils Biostratigraphy of Late Cretaceous–Paleocene Successions from Northern Jordan and Their Implications for Basin Analysis

Geosciences, 2023
Local geological and tectonic processes have been pivotal in shaping the diverse sedimentation patterns observed in Jordan, forming sub-basins characterized by elevated organic matter content (TOC). This study aims to characterize the Maastrichtian basin,
Albesher Hussein, Osama M. Al-Tarawneh, Mohammad Alqudah   +2 more
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Chemical sensitivity to the ratio of the cosmic-ray ionization rates of He and H2 in dense clouds [PDF]

, 2006
Aim: To determine whether or not gas-phase chemical models with homogeneous and time-independent physical conditions explain the many observed molecular abundances in astrophysical sources, it is crucial to estimate the uncertainties in the calculated ...
Baldwin, Bergin, Boger, Charnley, Dalgarno, E. Herbst, F. Selsis, G. Massacrier, Glassgold, Graedel, Herbst, Le Bourlot, Le Bourlot, Le Teuff, Lee, Pagani, Pineau des Forets, Shalabiea, Smith, Snell, Terzieva, V. Wakelam, Wakelam, Wakelam, Wakelam   +24 more
core   +3 more sources

Chemical Composition of RR Lyn – an Eclipsing Binary System with Am and λ Boo Type Components [PDF]

Journal of Astronomy and Space Sciences, 2017
High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea.
Yeuncheol Jeong, Alexander V. Yushchenko, Dmytry N. Doikov, Vira F. Gopka, Volodymyr O. Yushchenko   +4 more
doaj   +1 more source