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We study galactic enrichment with rapid neutron capture (r-process) elements in cosmological, magnetohydrodynamical simulations of a Milky Way-mass galaxy. We include a variety of enrichment models, based on either neutron star mergers or a…

Astrophysics of Galaxies · Physics 2022-03-30 Freeke van de Voort , Rüdiger Pakmor , Rebekka Bieri , Robert J. J. Grand

Neutron star mergers (NSM) are likely to be the main production sites for the rapid (r-) neutron capture process elements. We study the r-process enrichment of the stellar halo of the Milky Way through NSM, by tracing the typical r-process…

Astrophysics of Galaxies · Physics 2018-12-19 Pim van Oirschot , Gijs Nelemans , Onno Pols , Else Starkenburg

Small stellar systems like dwarf galaxies are suggested to be the main building blocks of our Galaxy by numerical simulations in Lambda CDM models. The existence of star streams like Sagittarius tidal stream indicates that dwarf galaxies…

Solar and Stellar Astrophysics · Physics 2019-05-13 Qian-Fan Xing , Gang Zhao , Wako Aoki , Satoshi Honda , Hai-Ning Li , Miho N. Ishigaki , Tadafumi Matsuno

The abundance of elements synthesized by the rapid neutron-capture process (r-process elements) of extremely metal-poor (EMP) stars in the Local Group galaxies gives us clues to clarify the early evolutionary history of the Milky Way halo.…

Astrophysics of Galaxies · Physics 2017-01-18 Yutaka Hirai , Yuhri Ishimaru , Takayuki R. Saitoh , Michiko S. Fujii , Jun Hidaka , Toshitaka Kajino

Chemical abundances and abundance ratios measured in galaxies provide precious information about the mechanisms, modes and time scales of the assembly of cosmic structures. Yet, the nucleogenesis and chemical evolution of elements heavier…

Astrophysics of Galaxies · Physics 2019-12-04 Donatella Romano , Francesca Matteucci , Zhi-Yu Zhang , Rob J. Ivison , Paolo Ventura

Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a…

Astrophysics of Galaxies · Physics 2019-08-16 B. Wehmeyer , C. Frohlich , B. Côté , M. Pignatari , F. -K. Thielemann

In this series of lectures I discuss the basic principles and the modelling of the chemical evolution of galaxies. In particular, I present models for the chemical evolution of the Milky Way galaxy and compare them with the available…

Astrophysics · Physics 2007-05-23 F. Matteucci

The astrophysical origins of $r$-process elements remain elusive. Neutron star mergers (NSMs) and special classes of core-collapse supernovae (rCCSNe) are leading candidates. Due to these channels' distinct characteristic timescales…

The chemical abundances of metal-poor stars are an excellent test bed by which to set new constraints on models of neutron-capture processes at low metallicity. Some r-process-rich (hereafter r-rich) metal-poor stars, such as HD221170, show…

Solar and Stellar Astrophysics · Physics 2010-10-25 Jiang Zhang , Wenyuan Cui , Bo Zhang

Understanding the origin of the elements has been a decades long pursuit, with many open questions still remaining. Old stars found in the Milky Way and its dwarf satellite galaxies can provide answers because they preserve clean elemental…

Solar and Stellar Astrophysics · Physics 2018-11-14 Anna Frebel

A long-standing scientific puzzle has been to explain the origin of the heaviest elements in the Universe and, more particularly, the production of the elements heavier than iron up to uranium. The rapid neutron capture process (or…

High Energy Astrophysical Phenomena · Physics 2023-03-14 Ina K. B. Kullmann

The role of compact binary mergers as the main production site of r-process elements is investigated by combining stellar abundances of Eu observed in the Milky Way, galactic chemical evolution (GCE) simulations, binary population synthesis…

Whether binary neutron star mergers are the only astrophysical site of rapid neutron-capture process ($r$-process) nucleosynthesis remains unknown. Collapsars associated with long gamma-ray bursts (GRBs) and hypernovae are promising…

High Energy Astrophysical Phenomena · Physics 2023-08-09 Long Li , Shu-Qing Zhong , Zi-Gao Dai

By adopting a chemical evolution model for the Milky Way already reproducing the evolution of several chemical elements, we compare our theoretical results with accurate and new stellar data of neutron capture elements and we are able to…

Astrophysics · Physics 2007-08-31 Gabriele Cescutti

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 (e.g., M5 and M15). In this scenario,…

Astrophysics of Galaxies · Physics 2017-07-26 Kenji Bekki , Takuji Tsujimoto

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 themselves and the star formation and…

Astrophysics · Physics 2009-11-07 J. W. Truran , J. J. Cowan , C. A. Pilachowski , C. Sneden

A brief overview of the r-process is given with an emphasis on the observational implications for this process. The conditions required for the major production of the heavy r-process elements (r-elements) with mass numbers A >130 are…

Astrophysics · Physics 2008-09-18 Yong-Zhong Qian

Neutron star mergers have been long considered as promising sites of heavy $r$-process nucleosynthesis. We overview observational evidence supporting this scenario including: the total amount of $r$-process elements in the Galaxy, extreme…

High Energy Astrophysical Phenomena · Physics 2018-10-17 Kenta Hotokezaka , Paz Beniamini , Tsvi Piran

Compact binary mergers involving at least one neutron star are promising sites for the synthesis of $\textit{r}$-process elements found in stars and planets. However, mergers can take place at significant offsets from their host galaxies,…

Astrophysics of Galaxies · Physics 2022-11-09 Benjamin Amend , Jonathan Zrake , Dieter H. Hartmann

One-zone Galactic Chemical Evolution (GCE) models have provided useful insights on a great wealth of average abundance patterns in many environments, especially for the Milky Way and its satellites. However, the scatter of such abundance…

Astrophysics of Galaxies · Physics 2023-04-12 Jinning Liang , Eda Gjergo , Xilong Fan