English
Related papers

Related papers: Neutron-Capture Element Trends in the Halo

200 papers

We present new abundance observations of neutron-capture elements in Galactic stars. These include new Hubble Space Telescope (HST) detections of the elements Ge, Zr and Pt in a group of 11 halo stars. Correlations between these elements…

Astrophysics · Physics 2007-05-23 John J. Cowan , Christopher Sneden

Neutron-capture elements in low metallicity Galactic halo stars vary widely both in overall contents and detailed abundance patterns. This review discusses recent observational results on the n-capture elements, discussing the implications…

Astrophysics · Physics 2009-11-07 C. Sneden , J. J. Cowan , J. E. Lawler

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the…

Astrophysics · Physics 2009-09-29 J. J. Cowan , C. Sneden , J. E. Lawler , E. A. Den Hartog

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…

Astrophysics of Galaxies · Physics 2015-06-17 Heather R. Jacobson , Anna Frebel

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy,…

Astrophysics · Physics 2009-11-06 J. J. Cowan , C. Sneden , J. W. Truran

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…

Astrophysics · Physics 2009-11-10 S. Honda , W. Aoki , T. Kajino , H. Ando , T. C. Beers , H. Izumiura , K. Sadakane , M. Takada-Hidai

This work describes a study of elemental abundances for 30 metal-poor stars whose chemical abundances provide excellent information for setting constraints on models of neutron-capture processes. Based on the abundances of main r- and weak…

Solar and Stellar Astrophysics · Physics 2015-06-12 Hongjie Li , Xiaojing Shen , Shuai Liang , Wenyuan Cui , Bo Zhang

In a short review of neutron-capture elemental abundances in Galactic halo stars, emphasis is placed on the use of these elements to estimate the age of the Galactic halo. Two prominent characteristics of neutron-capture elements in halo…

Astrophysics · Physics 2009-11-07 C. Sneden , J. E. Lawler , J. J. Cowan

New abundances for neutron-capture (n-capture) elements in a large sample of metal-poor giants from the Bond survey are presented. The spectra were acquired with the KPNO 4-m echelle and coude feed spectrographs, and have been analyzed…

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…

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…

Solar and Stellar Astrophysics · Physics 2011-06-07 John J. Cowan , Ian U. Roederer , Christopher Sneden , James E. Lawler

During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of…

Astrophysics · Physics 2007-05-23 John J. Cowan , Christopher Sneden

We present new Hubble Space Telescope (HST) abundance observations of the neutron-capture elements Ge, Zr, Os and Pt in a group of 11 Galactic halo stars, including the well studied r-process rich CS 22892-052 and the r-process poor, bright…

Astrophysics · Physics 2007-05-23 John J. Cowan , Christopher Sneden

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…

Solar and Stellar Astrophysics · Physics 2017-03-03 Misa Aoki , Yuhri Ishimaru , Wako Aoki , Shinya Wanajo

Neutron-capture elements, those with Z > 35, are the least well-understood in terms of nucleosynthesis and formation environments. The rapid neutron-capture, or r-process, elements are formed in the environments and/or remnants of massive…

Solar and Stellar Astrophysics · Physics 2016-06-22 Jamie C. Overbeek , Eileen D. Friel , Heather R. Jacobson

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…

Solar and Stellar Astrophysics · Physics 2010-10-25 Jiang Zhang , Wenyuan Cui , Bo Zhang

Neutron-capture-enhanced, metal-poor stars are of central importance to developing an understanding of the operation of the r-process in the early Galaxy, thought to be responsible for the formation of roughly half of all elements beyond…

Astrophysics · Physics 2009-11-10 T. C. Beers , P. S. Barklem , N. Christlieb , V. Hill

The framework for the interpretation of neutron-capture elements observed in Population II stars, established 20-25 years ago, is that these stars primarily exhibit r-process signatures, due to the inefficiency of the s-process at low…

Astrophysics · Physics 2009-11-07 Sean G. Ryan

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…

The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and…

Astrophysics · Physics 2009-11-07 J. W. Truran , J. J. Cowan , C. A. Pilachowski , C. Sneden
‹ Prev 1 2 3 10 Next ›