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Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first…

Astrophysics · Physics 2007-05-23 John J Cowan , Christopher Sneden , James W Truran , Debra L Burris

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

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…

Solar and Stellar Astrophysics · Physics 2014-07-21 Hongjie Li , Wenjuan Ma , Wenyuan Cui , Bo Zhang

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

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…

Astrophysics · Physics 2009-11-11 Bo Zhang , Kun Ma , Guide Zhou

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

Abundances of heavier elements (barium and beyond) in many neutron-capture-element-rich halo stars accurately replicate the solar system r-process pattern. However, abundances of lighter neutron-capture elements in these stars are not…

The very metal-poor star HE 0338-3945 shows a double-enhanced pattern of the neutron-capture elements. The study to this sample could make people gain a better understanding of s- and r-process nucleosynthesis at low metallicity. Using a…

Solar and Stellar Astrophysics · Physics 2010-10-22 Wenyuan Cui , Jiang Zhang , Zizhong Zhu , Bo Zhang

We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this…

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…

Solar and Stellar Astrophysics · Physics 2015-06-11 Hongjie Li , Shuai Liang , Wenyuan Cui , Bo Zhang

Heavy elements, those produced by neutron-capture reactions, have traditionally shown no star-to-star dispersion in all but a handful of metal-poor globular clusters (GCs). Recent detections of low [Pb/Eu] ratios or upper limits in several…

Astrophysics of Galaxies · Physics 2011-05-11 Ian U. Roederer

We present new observational benchmarks of rapid neutron-capture process (r-process) nucleosynthesis for elements at and between the first (A ~ 80) and second (A ~ 130) peaks. Our analysis is based on archival ultraviolet and optical…

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,…

Solar and Stellar Astrophysics · Physics 2018-04-04 François Spite , Monique Spite , Beatriz Barbuy , Piercarlo Bonifacio , Elisabetta Caffau , Patrick François

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

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

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 2017-08-23 J. J. Cowan , C. Sneden

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

Object LAMOST J020623.21+494127.9 (program star) in the thin disk of the Milky Way (MW) is reported as a highly r-process-enhanced (RPE) r-II star with[Eu/Fe]= +1.32 and [Fe/H]= -0.54. The chemical profile of the star reflects the intrinsic…

Solar and Stellar Astrophysics · Physics 2025-05-13 Muhammad Zeshan Ashraf , Wenyuan Cui , Hongjie Li

We obtained a high resolution, high signal-to-noise UV-blue spectrum of the extremely metal-poor red giant HD88609 to determine the abundances of heavy elements. Nineteen neutron-capture elements are detected in the spectrum. Our analysis…

Astrophysics · Physics 2009-06-23 Satoshi Honda , Wako Aoki , Yuhri Ishimaru , Shinya Wanajo

The CH star CS 31062-050 ([Fe/H]=-2.42) is one of the most useful stars yet discovered for evaluating the s-process in metal-poor stars. It is very abundant in heavy elements (e.g., [La/Fe]=2.2), and its relatively cool temperature and low…

Astrophysics · Physics 2009-11-10 Jennifer A. Johnson , Michael Bolte