Explorations of the r-processes : Comparisons between calculations and observations of low-metallicity stars

  title={Explorations of the r-processes : Comparisons between calculations and observations of low-metallicity stars},
  author={Karl Ludwig Kratz and Khalil Farouqi and Bernd Pfeiffer and James W. Truran and Christopher Sneden and J. J. Cowan},
  journal={The Astrophysical Journal},
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 consistent with the solar system pattern. These comparisons suggest contributions from two distinct types of r-process synthesis events, a so-called main r-process for the elements above the second r-process peak and a weak r-process for the lighter neutron… Expand
r-Process Enhanced Halo Stars
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 ofExpand
Constraints on the Nature of the s- and r-processes
Abstract Neutron-capture (Z > 30) elements are detected in many very metal-poor halo stars, and so they must have been manufactured by some of the earliest element donors in our Galaxy's history. TheExpand
Observational nuclear astrophysics: neutron-capture element abundances in old, metal-poor stars
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 ofExpand
Study of isotopic fractions and abundances of the neutron-capture elements in HD 175305
The chemical abundances of metal-poor stars are excellent sources of information for setting new constraints on models of Galactic chemical evolution at low metallicities. In this paper we present anExpand
Nucleosynthesis in the early galaxy
Recent observations of r-process-enriched metal-poor star abundances reveal a nonuniform abundance pattern for elements -->Z ≤ 47. Based on noncorrelation trends between elemental abundances as aExpand
The r-process in Metal-poor Stars and Black Hole Formation
Nucleosynthesis of heavy nuclei in metal-poor stars is generally ascribed to the r-process, as the abundance pattern in many such stars agrees with the inferred Solar r-process abundances.Expand
P o S ( N I CI X ) 0 1 4 r-Process Enhanced Halo Stars
Abundance observations indicate the presence of rapid-neu tron capture ( i.e., r-process) elements in old Galactic halo and globular cluster stars. These obser vations provide insight into the natureExpand
High-resolution abundance analysis of very metal-poor r-I stars
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 importantExpand
r-process enhanced metal-poor stars
In this review we summarize the current state of some aspects of observational studies of low metallicity stars that have been enriched with products of rapid-neutron-capture (r-process)Expand
The End of Nucleosynthesis: Production of Lead and Thorium in the Early Galaxy
We examine the Pb and Th abundances in 27 metal-poor stars (−3.1 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from HubbleSpaceExpand


r-Process Abundances and Chronometers in Metal-poor Stars
Rapid neutron-capture (i.e., r-process) nucleosynthesis calculations, employing internally consistent and physically realistic nuclear physics input (quasi-particle random-phase approximation (QRPA)Expand
Probing the Neutron‐Capture Nucleosynthesis History of Galactic Matter
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 themselvesExpand
In this paper we follow the Galactic enrichment of three easily observed light n-capture elements: Sr, Y, and Zr. Input stellar yields have been first separated into their respective main and weakExpand
The Rise of the s-Process in the Galaxy
From newly obtained high-resolution, high signal-to-noise ratio spectra the abundances of the elements La and Eu have been determined over the stellar metallicity range -3 < [Fe/H] < +0.3 in 159Expand
r-Process in Neutron Star Mergers.
Sufficient material is ejected to explain the amount of r-process nuclei in the Galaxy by decompression of neutron star material, and the calculated abundances fit the observed solar r-pattern excellently for nuclei that include and are heavier than the A approximately 130 peak. Expand
Stellar abundances in the early galaxy and two r-process components
We present quantitative predictions for the abundances of r-process elements in stars formed very early in the Galactic history using a phenomenological two-component r-process model based on theExpand
Genesis of the Heaviest Elements in the Milky Way Galaxy
The stellar abundances indicate an increasing contribution from the slow neutron-capture process at higher metallicities in the Galaxy, and the detection of thorium in halo and globular cluster stars offers a promising, independent age-dating technique that can put lower limits on the age of the Galaxy. Expand
The Chemical Composition and Age of the Metal-poor Halo Star BD +17°3248*
We have combined new high-resolution spectra obtained with the Hubble Space Telescope (HST )a nd ground-based facilities to make a comprehensive new abundance analysis of the metal-poor, halo star BDExpand
The astrophysical r-process: A comparison of calculations following adiabatic expansion with classical calculations based on neutron densities and temperatures
The rapid neutron-capture process (r-process) encounters unstable nuclei far from β-stability. Therefore its observable features, like the abundances, witness (still uncertain) nuclear structure asExpand
The r-Process-enriched Low-Metallicity Giant HD?115444
New high-resolution, very high signal-to-noise spectra of ultra-metal-poor (UMP) giant stars HD 115444 and HD 122563 have been gathered with the High-Resolution Echelle Spectrometer of the McDonaldExpand