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相关论文: Study of Neutron-Capture Element Abundances in Met…

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The chemical abundances of metal-poor stars are an excellent test bed by which to set new constraints on models of neutron-capture processes at low metallicity. Some r-process-rich (hereafter r-rich) metal-poor stars, such as HD221170, show…

太阳与恒星天体物理 · 物理学 2010-10-25 Jiang Zhang , Wenyuan Cui , Bo Zhang

The chemical abundances of the metal-poor stars in the stellar stream provide important information for setting constraints on models of neutron-capture processes. The study of these stars could give us a better understanding of r-process…

太阳与恒星天体物理 · 物理学 2015-06-11 Hongjie Li , Shuai Liang , Wenyuan Cui , Bo Zhang

We determine the abundances of neutron-capture elements from Sr to Eu for five very-metal-poor stars (-3<[Fe/H]<-2) in the Milky Way halo to reveal the origin of light neutron-capture elements. Previous spectroscopic studies have shown…

太阳与恒星天体物理 · 物理学 2017-03-03 Misa Aoki , Yuhri Ishimaru , Wako Aoki , Shinya Wanajo

Many works have attempted to investigate the astrophysical origin of the neutron-capture elements in the metalpoor star HD 140283. However, no definite conclusions have been drawn. In this work, using the abundancedecomposed approach, we…

太阳与恒星天体物理 · 物理学 2015-11-17 Ping Niu , Wenyuan Cui , Bo Zhang

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. Recent observations of the r-process-enriched star BD +17 3248 include new abundance…

太阳与恒星天体物理 · 物理学 2011-06-07 John J. Cowan , Ian U. Roederer , Christopher Sneden , James E. Lawler

We measured new abundances of so-called light neutron-capture of first peak elements using local thermodynamic equilibrium (LTE) 1D analysis; this analysis resulted in a sample of 11 very metal-poor stars, from [Fe/H]=-2.5 to [Fe/H]=-3.4,…

太阳与恒星天体物理 · 物理学 2018-04-04 François Spite , Monique Spite , Beatriz Barbuy , Piercarlo Bonifacio , Elisabetta Caffau , Patrick François

The astrophysical origin of the rapid neutron-capture process (r-process), which produces about half of the elements heavier than iron, remains uncertain. The oldest, most metal-poor stars preserve the chemical signatures of early…

We present the abundance analyses for the neutron-capture elements, and discuss the observed abundance distributions in very metal-poor stars with excesses of r-process elements. As has been found by previous abundance studies, the…

天体物理学 · 物理学 2009-11-10 S. Honda , W. Aoki , T. Kajino , H. Ando , T. C. Beers , H. Izumiura , K. Sadakane , M. Takada-Hidai

The chemical abundances of metal-poor stars provide a great deal of information regarding the individual nucleosynthetic processes that created the observed elements and the overall process of chemical enrichment of the galaxy since the…

星系天体物理 · 物理学 2015-06-17 Heather R. Jacobson , Anna Frebel

To better characterize the abundance patterns produced by the r-process, we have derived new abundances or upper limits for the heavy elements zinc (Zn), yttrium (Y), lanthanum (La), europium (Eu), and lead (Pb). Our sample of 161…

太阳与恒星天体物理 · 物理学 2015-05-20 I. U. Roederer , J. J. Cowan , A. I. Karakas , K. -L. Kratz , M. Lugaro , J. Simmerer , K. Farouqi , C. Sneden

The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s+r stars, since they show…

天体物理学 · 物理学 2009-11-11 Bo Zhang , Kun Ma , Guide Zhou

Recent observations of r-process-enriched metal-poor star abundances reveal a non-uniform abundance pattern for elements $Z\leq47$. Based on non-correlation trends between elemental abundances as a function of Eu-richness in a large sample…

天体物理学 · 物理学 2009-11-13 F. Montes , T. C. Beers , J. Cowan , T. Elliot , K. Farouqi , R. Gallino , M. Heil , K. -L. Kratz , B. Pfeiffer , M. Pignatari , H. Schatz

We present our chemical abundance investigation of the metal-poor ([Fe/H]=-1.60 dex), r-process-enriched ([Eu/Fe]=0.73 dex) halo star HD 20 using novel and archival high-resolution spectra at outstanding signal-to-noise ratios. By combining…

In a brief review of abundances neutron-capture elements (Z > ~30) in metal-poor halo stars, attention is called to their star-to-star scatter, the dominance of r-process synthesis at lowest metallicities, the puzzle of the lighter members…

天体物理学 · 物理学 2016-11-03 C. Sneden , J. J. Cowan , J. W. Truran

We present new abundance determinations of neutron-capture elements Ge, Zr, Os, Ir, and Pt in a sample of 11 metal-poor (-3.1 <= [Fe/H] <= -1.6) Galactic halo giant stars, based on Hubble Space Telescope UV and Keck I optical…

The abundance patterns of metal-poor stars provide us a wealth of chemical information about various stages of the chemical evolution of the Galaxy. In particular, these stars allow us to study the formation and evolution of the elements…

天体物理学 · 物理学 2009-04-14 Anna Frebel

We present a nearly complete rapid neutron-capture process (r-process) chemical inventory of the metal-poor ([Fe/H] = -1.46 +/- 0.10) r-process-enhanced ([Eu/Fe] = +1.32 +/- 0.08) halo star HD 222925. This abundance set is the most complete…

The chemical abundances of metal-poor stars provide important clues to explore stellar formation history and set significant constraints on models of the r-process. In this work, we find that the abundance patterns of the light and iron…

太阳与恒星天体物理 · 物理学 2014-07-21 Hongjie Li , Wenjuan Ma , Wenyuan Cui , Bo Zhang

Rapid neutron-capture (i.e., r-process) nucleosynthesis calculations, employing internally consistent and physically realistic nuclear physics input (QRPA beta-decay rates and the ETFSI-Q nuclear mass model), have been made. These…

Moderately r-process-enriched stars (r-I) are at least four times as common as those that are greatly enriched in r-process elements (r-II), and the abundances in their atmospheres are important tools for obtaining a better understanding of…

太阳与恒星天体物理 · 物理学 2015-06-19 C. Siqueira-Mello , V. Hill , B. Barbuy , M. Spite , F. Spite , T. C. Beers , E. Caffau , P. Bonifacio , R. Cayrel , P. François , H. Schatz , S. Wanajo
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