Can Neutron-star Mergers Explain the r-process Enrichment in Globular Clusters?

  title={Can Neutron-star Mergers Explain the r-process Enrichment in Globular Clusters?},
  author={Michael Zevin and Kyle Kremer and Daniel M. Siegel and Scott Coughlin and Benny T.-H. Tsang and Christopher P. L. Berry and Vicky Kalogera},
  journal={The Astrophysical Journal},
Star-to-star dispersion of r-process elements has been observed in a significant number of old, metal-poor globular clusters. We investigate early-time neutron-star mergers as the mechanism for this enrichment. Through both numerical modeling and analytical arguments, we show that neutron-star mergers cannot be induced through dynamical interactions early in the history of the cluster, even when the most liberal assumptions about neutron-star segregation are assumed. Therefore, if neutron-star… 

Figures and Tables from this paper

On the Rate of Neutron Star Binary Mergers from Globular Clusters
The first detection of gravitational waves from a neutron star - neutron star (NS-NS) merger, GW170817, and the increasing number of observations of short gamma-ray bursts (SGRBs) have greatly
R-process enrichment in ultrafaint dwarf galaxies
We study the enrichment and mixing of r-process elements in ultrafaint dwarf galaxies (UFDs). We assume that r-process elements are produced by neutron-star mergers (NSMs), and examine multiple
GW170817 --the first observed neutron star merger and its kilonova: Implications for the astrophysical site of the r-process
  • D. Siegel
  • Physics
    The European Physical Journal A
  • 2019
Abstract.The first neutron star (NS) merger observed by advanced LIGO and Virgo, GW170817, and its fireworks of electromagnetic counterparts across the entire electromagnetic spectrum marked the
Internal R-process Abundance Spread of M15 and a Single Stellar Population Model
The member stars in globular cluster M15 show a substantial spread in the abundances of r-process elements. We argue that a rare and prolific r-process event enriched the natal cloud of M15 in an
Collapsar R-process Yields Can Reproduce [Eu/Fe] Abundance Scatter in Metal-poor Stars
It is unclear if neutron star mergers can explain the observed r-process abundances of metal-poor stars. Collapsars, defined here as rotating massive stars whose collapse results in a rapidly
Forward Modeling of Double Neutron Stars: Insights from Highly Offset Short Gamma-Ray Bursts
We present a detailed analysis of two well-localized, highly-offset short gamma-ray bursts---GRB 070809 and GRB 090515---investigating the kinematic evolution of their progenitors from compact object
The Stars in M15 Were Born with the r-process
High-resolution spectroscopy of stars on the red giant branch (RGB) of the globular cluster M15 has revealed a large (~1 dex) dispersion in the abundances of r-process elements, like Ba and Eu.
Heavy Double Neutron Stars: Birth, Midlife, and Death
Radio pulsar observations probe the lives of Galactic double neutron star (DNS) systems while gravitational waves enable us to study extragalactic DNS in their final moments. By combining
The expansion of stripped-envelope stars: Consequences for supernovae and gravitational-wave progenitors
Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars
On the origin of GW190425
The LIGO/Virgo collaborations recently announced the detection of a likely binary neutron star merger, GW190425. The total mass of GW190425 is significantly larger than the masses of Galactic double


The main astronomical source of r-process elements has not yet been identified. One plausible site is neutron star mergers (NSMs), but from perspective of the Galactic chemical evolution, it has been
Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy
We quantify the stellar abundances of neutron-rich r-process nuclei in cosmological zoom-in simulations of a Milky Way-mass galaxy from the Feedback In Realistic Environments project. The galaxy is
Formation of Globular Clusters with Internal Abundance Spreads in r-Process Elements: Strong Evidence for Prolonged Star Formation
Several globular clusters (GCs) in the Galaxy are observed to show internal abundance spreads in r-process elements (e.g., Eu). We here propose a new scenario which explains the origin of these GCs
Neutron star binary orbits in their host potential: effect on early r-process enrichment
Coalescing neutron star binary (NSB) systems are primary candidates for r-process enrichment of galaxies. The recent detection of r-process elements in ultrafaint dwarf (UFD) galaxies and the
On Neutron Star Mergers as the Source of r-process-enhanced Metal-poor Stars in the Milky Way
We model the history of Galactic r-process enrichment using high-redshift, high-resolution zoom cosmological simulations of a Milky Way (MW) type halo. We assume that all r-process sources are
Simulating neutron star mergers as r-process sources in ultrafaint dwarf galaxies
To explain the high observed abundances of r-process elements in local ultra- faint dwarf (UFD) galaxies, we perform cosmological zoom simulations that include r-process production from neutron star
Neutron Star Mergers Might Not Be the Only Source of r-process Elements in the Milky Way
Probing the origin of r-process elements in the universe represents a multidisciplinary challenge. We review the observational evidence that probes the properties of r-process sites, and address them
r-process Enrichment of the Ultra-faint Dwarf Galaxies by Fast-merging Double-neutron Stars
The recent aLIGO/aVirgo discovery of gravitational waves from the neutron star merger (NSM) GW170817 and the follow up kilonova observations have shown that NSMs produce copious amount of r-process
Formation and evolution of compact binaries in globular clusters – II. Binaries with neutron stars
In this paper, the second of a series, we study the stellar dynamical and evolutionary processes leading to the formation of compact binaries containing neutron stars (NSs) in dense globular
Compact Stellar Binary Assembly in the First Nuclear Star Clusters and r-Process Synthesis in the Early Universe
Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical