Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process

Abstract

Context. Thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal-poor stars for which measurements of detailed abundances exist. [...] These data hold important clues on the nature of the contribution of the first stellar generations to the enrichment of our Galaxy. Aims. We aim to explain the scatter in Sr, Ba, Y, and Eu abundance ratio diagrams unveiled by the metal-poor halo stars. Methods. We computed inhomogeneous chemical evolution models for the Galactic halo assuming different scenarios for the r-process site: the electron-capture supernovae (EC) and the magnetorotationally driven (MRD) supernovae scenario. We also considered models with and without the contribution of fast-rotating massive stars (spinstars) to an early enrichment by the s-process. A detailed comparison with the now large sample of stars with measured abundances of Sr, Ba, Y, Eu, and Fe is provided (both in terms of scatter plots and number distributions for several abundance ratios). Results. The scatter observed in these abundance ratios of the very metal-poor stars (with [Fe/H] < -2.5) can be explained by combining the s-process production in spinstars, and the r-process contribution coming from massive stars. For the r-process we have developed models for both the EC and the MRD scenario that match the observations. Conclusions. With the present observational and theoretical constraints we cannot distinguish between the EC and the MRD scenario in the Galactic halo. Independently of the r-process scenarios adopted, the production of elements by an s-process in spinstars is needed to reproduce the spread in abundances of the light neutron capture elements (Sr and Y) over heavy neutron capture elements (Ba and Eu). We provide a way to test our suggestions by means of the distribution of the Ba isotopic ratios in a [Ba/Fe] or [Sr/Ba] vs. [Fe/H] diagram.

arXiv comment14 pages, 7 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (49)

• The Progenitor Stars of Gamma-Ray Bursts
• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample
• Energy Input and Mass Redistribution by Supernovae in the Interstellar Medium
• The Rise of the s-Process in the Galaxy
• Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium
• Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way
• First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy
• The Chemical Composition and Age of the Metal-Poor Halo Star BD +17^\circ 3248
• The r-Process Enriched Low Metallicity Giant HD 115444
• The evolution of the Milky Way from its earliest phases : constraints on stellar nucleosynthesis
• The s process in asymptotic giant branch stars of low metallicity and the composition of carbon-enhanced metal-poor stars
• Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars
• First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants
• A holistic approach to carbon-enhanced metal-poor stars
• A strong case for fast stellar rotation at very low metallicities
• HE1327-2326, an unevolved star with [Fe/H]<-5.0. I. A Comprehensive Abundance Analysis
• Production of Light Element Primary Process nuclei in neutrino-driven winds
• Non-standard s process in low metallicity massive rotating stars
• The Frequency of Carbon-Enhanced Metal-Poor Stars in the Galaxy from the HERES sample
• The s process in massive stars at low metallicity. Effect of primary N14 from fast rotating stars
• Spectroscopic Studies of Very Metal-Poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements
• The stellar content of the Hamburg/ESO survey. IV. Selection of candidate metal-poor stars
• Nucleosynthesis in Electron Capture Supernovae of AGB Stars
• The r-process in proto-neutron-star wind revisited
• High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical Compositions
• New fission fragment distributions and r-process origin of the rare-earth elements
• Dynamical r-process studies within the neutrino-driven wind scenario and its sensitivity to the nuclear physics input
• New Extremely Metal-Poor Stars in the Galactic Halo
• Stellar Archaeology -- Exploring the Universe with Metal-Poor Stars
• s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
• The s-process in the Galactic halo: the fifth signature of spinstars in the early Universe?
• CS 30322-023: an ultra metal-poor TP-AGB star?
• The chemical evolution of Barium and Europium in the Milky Way
• A new imprint of fast rotators: low 12C/13C ratios in extremely metal-poor halo stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) IV. Detailed abundance analysis and age dating of the strongly r-process enhanced stars CS 29491-069 and HE 1219-0312
• An inhomogeneous model for the Galactic halo: a possible explanation for the spread observed in s- and r-process elements
• The Isotopic Mixture of Barium in the Metal-poor Subgiant HD 140283
• Carbon and Strontium Abundances of Metal-Poor Stars
• Chemical composition of carbon-rich, very metal-poor subgiant LP625-44 observed with the Subaru/HDS
• Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. IV. The alpha-Element-Enhanced Metal-Poor Star BS16934-002
• The Hobby-Eberly Telescope "Chemical Abundances of Stars in the Halo" (CASH) Project. I. The Lithium-, s-, and r-Enhanced Metal-Poor Giant HKII 17435-00532
• The barium isotopic mixture for the metal-poor subgiant star HD140283
• The stellar content of the Hamburg/ESO survey VI. The metallicity distribution of main-sequence turnoff stars in the Galactic halo
• Explaining the Sr and Ba Scatter in Extremely Metal-Poor Stars
• The Barium Isotopic Abundance in the Metal-Poor Star HD140283
• The barium isotopic fractions in five metal-poor stars
• The effects of stellar winds of fast-rotating massive stars in the earliest phases of the chemical enrichment of the Galaxy

Cited by in corpus (73)

• Chemical evolution with rotating massive star yields: I. The solar neighbourhood and the s-process elements
• The r-process nucleosynthesis in the various jet-like explosions of magnetorotational core-collapse supernovae
• Galactic evolution of rapid neutron capture process abundances: the inhomogeneous approach
• From Nuclei to the Cosmos: Tracing Heavy-Element Production with the Oldest Stars
• The History of R-Process Enrichment in the Milky Way
• The role of neutron star mergers in the chemical evolution of the Galactic halo
• The EMBLA Survey -- Metal-poor stars in the Galactic bulge
• Relative contributions of the weak, main and fission-recycling r-process
• The first stars: CEMP--no stars and signatures of spinstars
• The first carbon-enhanced metal-poor star found in the Sculptor dwarf spheroidal
• On the formation of neutron stars via accretion-induced collapse in binaries
• r-process Production Sites as inferred from Eu Abundances in Dwarf Galaxies
• The early days of the Sculptor dwarf spheroidal galaxy
• A new delay time distribution for merging neutron stars tested against Galactic and cosmic data
• High-resolution abundance analysis of red giants in the globular cluster NGC 6522
• The s Process and Beyond
• Cosmic Neutron Star Merger Rate and Gravitational Waves constrained by the R Process Nucleosynthesis
• Galactic Chemical Evolution: the Impact of the 13C-pocket Structure on the s-process Distribution
• Abundances of carbon-enhanced metal-poor stars as constraints on their formation
• Code dependencies of pre-supernova evolution and nucleosynthesis in massive stars: Evolution to the end of core helium burning
• Origin of neutron capture elements with the Gaia-ESO survey: the evolution of s- and r-process elements across the Milky Way
• Phosphorus-rich stars with unusual abundances are challenging theoretical predictions
• Abundance patterns of the light neutron-capture elements in very and extremely metal-poor stars
• The chemical evolution of r-process elements from neutron star mergers: the role of a 2-phase interstellar medium
• The Gaia-ESO Survey: A new approach to chemically characterising young open clusters II. Abundances of the neutron-capture elements Cu, Sr, Y, Zr, Ba, La, and Ce
• Enrichment of Zinc in galactic chemodynamical evolution models
• An inefficient dwarf: Chemical abundances and the evolution of the Ursa Minor dwarf spheroidal galaxy
• High-resolution abundance analysis of red giants in the metal-poor bulge globular cluster HP~1
• The detailed chemical abundance patterns of accreted halo stars from the optical to infrared
• The R-Process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
• Neutron star binary orbits in their host potential: effect on early r-process enrichment
• Evolution of neutron capture elements in dwarf galaxies
• Constraints on stellar rotation from the evolution of Sr and Ba in the Galactic halo
• Modelling the chemical evolution of Zr, La, Ce and Eu in the Galactic discs and bulge
• Origin of highly $r$-process-enhanced stars in a cosmological zoom-in simulation of a Milky Way-like galaxy
• Simulating Metal Mixing of Both Common and Rare Enrichment Sources in a Low Mass Dwarf Galaxy
• The Origin of the Heaviest Metals in Most Ultra-Faint Dwarf Galaxies
• Enrichment of Strontium in Dwarf Galaxies
• Looking for imprints of the first stellar generations in metal-poor bulge field stars
• Manganese spread in Ursa Minor as a proof of sub-classes of type Ia supernovae
• The cerium content of the Milky Way as revealed by Gaia DR3 GSP-Spec abundances
• The formation of the Milky Way halo and its dwarf satellites: A NLTE-1D abundance analysis. V. The Sextans galaxy
• Neutron stars mergers in a stochastic chemical evolution model: impact of time delay distributions
• 2D chemical evolution models II. Effects of multiple spiral arm patterns on O, Eu, Fe and Ba abundance gradients
• Inhomogeneous Galactic Chemical Evolution: Modelling Ultra-Faint Dwarf Galaxies of the Large Magellanic Cloud
• The Gaia-ESO survey: placing constraints on the origin of r-process elements
• Chrono-chemodynamical analysis of the globular cluster NGC 6355: Looking for the fundamental bricks of the Bulge
• Time evolution of Ce as traced by APOGEE using giant stars observed with the Kepler, TESS and K2 missions
• Observational constraints on the origin of the elements. VI. Origin and evolution of neutron-capture elements as probed by the Gaia-ESO survey
• Explaining the ${}^{12}\text{C}{/}^{13}\text{C}$ ratio in the Galactic halo: the contribution from shell mergers in primordial massive stars
• Nucleosynthesis signatures of neutrino-driven winds from proto-neutron stars: a perspective from chemical evolution models
• The Pristine Inner Galaxy Survey (PIGS) IX. The largest detailed chemical analysis of very metal-poor stars in the Sagittarius dwarf galaxy
• Chemical Evolution of R-process Elements in Stars (CERES). III. Chemical abundances of neutron capture elements from Ba to Eu
• Observational constraints on the origin of the elements. IX. 3D NLTE abundances of metals in the context of Galactic Chemical Evolution Models and 4MOST
• Heavy elements in old very metal-rich stars
• Neutrino-driven Core-collapse Supernova Yields in Galactic Chemical Evolution
• Unlocking the mystery of Sr synthesis in the early Galaxy through analysis of barium isotopes in very metal-poor stars
• Does the chemical signature of TYC 8442-1036-1 originate from a rotating massive star that died in a faint explosion?
• The origin of elements: the need for UV spectra
• Neutron-Capture Element Signatures in Globular Clusters: Insights from the Gaia-ESO Survey
• MINCE III. Detailed chemical analysis of the UVES sample
• The oldest stars of the bulge: new information on the ancient Galaxy
• The neutron-capture and alpha-elements abundance ratios scatter in old stellar populations. Cosmological simulations of the stellar halo
• Dependence of the Sr-to-Ba and Sr-to-Eu Ratio on the Nuclear Equation of State in Metal Poor Halo Stars
• Modelling the chemical evolution of the Milky Way
• How does the stellar disk of the Milky Way get its gas?
• Th/Eu abundance ratio of red giants in the Kepler Field
• Barium lines in high-quality spectra of two metal-poor giants in the Galactic halo
• Universality and variability of the heavy r-process element abundance pattern from a nonequilibrium approach
• The COMBS Survey -- III. The Chemodynamical Origins of Metal-Poor Bulge Stars
• Closing remarks and Outlook
• Detailed Abundance Determination of Metal-Poor Stars with X-Shooter I. Unusual Chemistry in Halo Stars
• UVES analysis of red giants in the bulge globular cluster NGC 6522