Neutron star binary orbits in their host potential: effect on early r-process enrichment

Abstract

Coalescing neutron star binary (NSB) systems are primary candidates for $r$-process enrichment of galaxies. The recent detection of $r$-process elements in ultra-faint dwarf (UFD) galaxies and the abundances measured in classical dwarfs challenges the NSB merger scenario both in terms of coalescence time scales and merger locations. In this paper, we focus on the dynamics of NSBs in the gravitational potentials of different types of host galaxies and on its impact on the subsequent galactic enrichment. We find that, for a $\sim t^{-1}$ delay time distribution, even when receiving a low kick ($\sim 10\mathrm{km}{\mathrm{s}}^{-1}$) from the second supernova explosion, in shallow dwarf galaxy potentials NSBs tend to merge with a large off-set from the host galaxy. This results in a significant geometrical dilution of the amount of produced $r-$process elements that fall back and pollute the host galaxy gas reservoir. The combination of dilution and small number statistics produces a large scatter in the expected $r$-process enrichment within a single UFD or classical dwarf galaxy. Comparison between our results and observed europium abundances reveals a tension that even a systematic choice of optimistic parameters in our models cannot release. Such a discrepancy could point to the need of additional $r$-process production sites that suffer less severe dilution or to a population of extremely fast merging binaries.

18 pages, 11 figures, MNRAS accepted

References in corpus (47)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The Gaia mission
• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• Multi-messenger Observations of a Binary Neutron Star Merger
• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. II. UV, Optical, and Near-IR Light Curves and Comparison to Kilonova Models
• Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
• A kilonova as the electromagnetic counterpart to a gravitational-wave source
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
• Formation of Double Neutron Star Systems
• Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. III. Optical and UV Spectra of a Blue Kilonova From Fast Polar Ejecta
• The Evolution of Compact Binary Star Systems
• Neutrino-driven winds from neutron star merger remnants
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. V. Rising X-ray Emission from an Off-Axis Jet
• Neutron Star Mergers and Nucleosynthesis of Heavy Elements
• Kilonova from post-merger ejecta as an optical and near-infrared counterpart of GW170817
• First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy
• The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
• The dynamical mass ejection from binary neutron star mergers: Radiation-hydrodynamics study in general relativity
• AT2017gfo: an anisotropic and three-component kilonova counterpart of GW170817
• The stellar halo of the Galaxy
• Neutron-capture elements in the very metal-poor star HD122563
• The rotation curves shapes of late-type dwarf galaxies
• Analytical representations of unified equations of state of neutron-star matter
• Complete element abundances of nine stars in the r-process galaxy Reticulum II
• On r-process nucleosynthesis from matter ejected in binary neutron starmergers
• An R-process enhanced star in the dwarf galaxy Tucana III
• The role of neutron star mergers in the chemical evolution of the Galactic halo
• VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy
• The Star Formation Histories of Local Group Dwarf Galaxies III. Characterizing Quenching in Low-Mass Galaxies
• Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process
• The Gravitational waves merger time distribution of binary neutron star systems
• Nucleosynthesis in Magnetically Driven Jets from Collapsars
• r-process Production Sites as inferred from Eu Abundances in Dwarf Galaxies
• Natal Kicks and Time Delays in Merging Neutron Star Binaries - Implications for r-process nucleosynthesis in Ultra Faint Dwarfs and in the Milky Way
• Nine New Metal-Poor Stars on the Subgiant and Red Horizontal Branches with High Levels of r-process Enhancement
• A new delay time distribution for merging neutron stars tested against Galactic and cosmic data
• Distribution of High-Mass X-ray Binaries in the Milky Way
• Chemical Abundance Analysis of Tucana III, the Second $r$-process Enhanced Ultra-Faint Dwarf Galaxy
• Simulating Neutron Star Mergers as r-process Sources in Ultra Faint Dwarf Galaxies
• An inefficient dwarf: Chemical abundances and the evolution of the Ursa Minor dwarf spheroidal galaxy
• Models for the 3-D axisymmetric gravitational potential of the Milky Way Galaxy - A detailed modelling of the Galactic disk
• On the Impact of Neutron Star Binaries Natal-Kick Distribution on the Galactic r-process Enrichment

Cited by in corpus (21)

• Origin of the Heaviest Elements: the Rapid Neutron-Capture Process
• Kilonovae
• Numerical Relativity Simulations of the Neutron Star Merger GW170817: Long-Term Remnant Evolutions, Winds, Remnant Disks, and Nucleosynthesis
• GW170817$-$the first observed neutron star merger and its kilonova: implications for the astrophysical site of the r-process
• Evidence from Disrupted Halo Dwarfs that $r$-process Enrichment via Neutron Star Mergers is Delayed by $\gtrsim 500$ Myrs
• Mapping dynamical ejecta and disk masses from numerical relativity simulations of neutron star mergers
• Can Neutron-Star Mergers Explain the r-process Enrichment in Globular Clusters?
• Evidence for $\gtrsim 4$ Gyr timescales of neutron star mergers from Galactic archaeology
• Collapsar R-Process Yields Can Reproduce [Eu/Fe] Abundance Scatter in Metal-Poor Stars
• Evolution of neutron capture elements in dwarf galaxies
• Modelling the chemical evolution of Zr, La, Ce and Eu in the Galactic discs and bulge
• Collapsars as Sites of r-process Nucleosynthesis: Systematic Near-Infrared Follow-up of Type Ic-BL Supernovae
• Neutron-capture elements in dwarf galaxies I: Chemical clocks & the short timescale of the r-process
• Neutron stars mergers in a stochastic chemical evolution model: impact of time delay distributions
• Stellar Signatures of Inhomogeneous Big Bang Nucleosynthesis
• Dynamical evolution of massive perturbers in realistic multi-component galaxy models I: implementation and validation
• Binary neutron star merger in common envelope jet supernovae
• The impact of turbulent mixing on the galactic r-process enrichment by binary neutron star mergers
• Europium enrichment and hierarchical formation of the Galactic halo
• Did a Kilonova Set Off in Our Galactic Backyard 3.5 Myr ago?
• Towards a paradigm change in the main heavy r-process nucleosynthesis sites