Universality and variability of the heavy r-process element abundance pattern from a nonequilibrium approach

Abstract

A striking feature in the observed chemical composition of the majority of stars is the universality of the relative abundances of the heavy elements, although some outliers exist. We demonstrate that a nonequilibrium freeze-out approach provides a natural way of accounting for the typical abundance pattern and its variation. Here, we use a phenomenological method to characterize the coarse-grained distribution of heavy $r$-process elements in several astrophysical objects. The Lagrange parameters show only minor fluctuations when comparing different stars. Larger deviations are observed in stars with low metallicity. The variations in the Lagrange parameters for these stars are presented. The determination of the Lagrange parameters can be instrumental in identifying possible sources for the formation of heavy elements. In particular, density fluctuations are considered as a source for the production of heavy elements in the early Universe.

23 pages, 6 figures, 4 tables

References in corpus (58)

• The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries
• Origin of the Heaviest Elements: the Rapid Neutron-Capture Process
• Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers
• Identification of strontium in the merger of two neutron stars
• Collapsars as a major source of r-process elements
• Neutron Star Mergers and Nucleosynthesis of Heavy Elements
• Neutron Star Mergers Might not be the Only Source of r-Process Elements in the Milky Way
• Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars
• R-Process Abundances and Chronometers in Metal-Poor Stars
• The Origin of r-Process Elements in the Milky Way
• The Role of Fission in Neutron Star Mergers and its Impact on the r-Process Peaks
• Galactic evolution of rapid neutron capture process abundances: the inhomogeneous approach
• From Nuclei to the Cosmos: Tracing Heavy-Element Production with the Oldest Stars
• Symmetry energy impact in simulations of core-collapse supernovae
• On the nuclear robustness of the r process in neutron-star mergers
• Neutron Star Mergers as sites of r-process Nucleosynthesis and Short Gamma-Ray Bursts
• Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy
• The History of R-Process Enrichment in the Milky Way
• SkyNet: A modular nuclear reaction network library
• Neutron-capture elements in the very metal-poor star HD88609: another st ar with excesses of light neutron-capture elements
• The role of neutron star mergers in the chemical evolution of the Galactic halo
• Enrichment of r-process elements in dwarf spheroidal galaxies in chemo-dynamical evolution model
• Neutron Star Mergers as the Origin of r-Process Elements in the Galactic Halo Based on the Sub-halo Clustering Scenario
• The R-Process Alliance: A Comprehensive Abundance Analysis of HD 222925, a Metal-Poor Star with an Extreme R-Process Enhancement of [Eu/H] = -0.14
• Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process
• How many nucleosynthesis processes exist at low metallicity?
• End-to-end kilonova models of neutron-star mergers with delayed black-hole formation
• Cold r-Process in Neutrino-Driven Winds
• Galactic Simulations of r-process Elemental Abundances
• Actinide-rich and Actinide-poor $r$-Process Enhanced Metal-Poor Stars do not Require Separate $r$-Process Progenitors
• On the origin of the Galactic thin and thick discs, their abundance gradients and the diagnostic potential of their abundance ratios
• r-process enrichment of ultra-faint dwarf galaxies by fast merging double neutron stars
• Element abundance patterns in stars indicate fission of nuclei heavier than uranium
• The state of matter in simulations of core-collapse supernovae -- Reflections and recent developments
• Stochastic Chemical Evolution of Galactic Subhalos and the Origin of r-Process Elements
• Nuclear Partition Functions at Temperatures Exceeding 10^10 K
• Neutron star mergers as the astrophysical site of the r-process in the Milky Way and its satellite galaxies
• Using failed supernovae to constrain the Galactic r-process element production
• The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks
• The R-Process Alliance: J1521-3538, a very metal-poor, extremely r-process-enhanced star with [Eu/Fe]=+2.2, and the class of r-III stars
• The SAGA Survey. IV. The Star Formation Properties of 101 Satellite Systems around Milky Way-mass Galaxies
• On Neutron Star Mergers as the Source of r-process Enhanced Metal Poor Stars in the Milky Way
• r-process Abundance Patterns in the Globular Cluster M92
• Decoding the compositions of four bright $r$-process-enhanced stars
• Synthesis of thorium and uranium in asymptotic giant branch stars
• Chemical Evolution of R-process Elements in Stars (CERES): IV. An observational run-up of the third r-process peak with Hf, Os, Ir, and Pt
• Reanalysis of neutron-capture elements in the benchmark r-rich star CS 31082-001
• Impact of nuclear matter properties on the nucleosynthesis and the kilonova from binary neutron star merger ejecta
• Employing ternary fission of ${}^{242}$Pu as a probe of very neutron rich matter
• Inference of multi-channel r-process element enrichment in the Milky Way using binary neutron star merger observations
• Correlation between U/Th and Pb/Os abundance ratios and its application in nuclear cosmochronology
• Primordial black-hole formation and heavy r-process element synthesis from the cosmological QCD transition. Two aspects of an inhomogeneous early Universe
• An Actinide-boost Star Discovered in the Gaia-Sausage-Enceladus
• Heavy element abundances from a universal primordial distribution
• Nucleosynthesis and the chemical enrichment of galaxies
• Metal-Poor Stars in the Milky Way System
• Complete survey of r-process conditions: the (un-)robustness of the r-process(-es)
• Mergers Fall Short: Non-merger Channels Required for Galactic Heavy Element Production