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Related papers: The R-Process Alliance: Chemo-Dynamically Tagged G…

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The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars (with metallicities down to [Fe/H]\sim-5.5) are relics from the…

Astrophysics of Galaxies · Physics 2015-05-30 Anna Frebel

RR Lyrae stars in the Milky Way are good tracers to study the kinematic behaviour and spatial distribution of older stellar populations. A recently established well documented sample of 217 RR Lyr stars with V<12.5 mag, has been used to…

Astrophysics · Physics 2009-11-11 Gisela Maintz , Klaas S. de Boer

Probing the origin of r-process elements in the universe represents a multi-disciplinary challenge. We review the observational evidence that probe the properties of r-process sites, and address them using galactic chemical evolution…

We search for the existence of chemically-distinct stellar components in the solar neighbourhood using published data. Extending earlier work, we show that when the abundances of Fe, alpha elements, and the r-process element Eu are…

Astrophysics of Galaxies · Physics 2015-05-19 Julio F. Navarro , Mario G. Abadi , Kim A. Venn , Kenneth C. Freeman , Borja Anguiano

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 enriched with r-process elements by binary…

Astrophysics of Galaxies · Physics 2015-06-22 Freeke van de Voort , Eliot Quataert , Philip F. Hopkins , Dusan Keres , Claude-Andre Faucher-Giguere

Context. In recent years, the R-Process Alliance (RPA) has conducted a successful search for stars enhanced in elements produced by the rapid neutron-capture (r-)process. In particular, the RPA has uncovered a number of stars strongly…

The third r-process peak (Os, Ir, Pt) is poorly understood due to observational challenges, with spectral lines located in the blue or near-ultraviolet region of stellar spectra. These challenges need to be overcome for a better…

The Galactic halo is supposed to form from merging with nearby dwarf galaxies. In order to probe different components of the Galactic halo, we have applied the Gaussian Mixture Models method to a selected sample of metal poor stars with…

Astrophysics of Galaxies · Physics 2021-06-23 Xilong Liang , Yuqin Chen , Jingkun Zhao , Gang Zhao

We applied Stars' Galactic Origin (StarGO) algorithm in 7D space (i.e., [Fe/H], [Mg/Fe], [Al/Fe], $L_{z}$, $J_{r}$, $J_{z}$, $E$) to analyze stars in the inner halo with APOGEE DR17. We identified some known substructures, including…

Astrophysics of Galaxies · Physics 2025-04-03 Zhongcheng Li , Cuihua Du , Haoyang Liu , Dashuang Ye

During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of…

Astrophysics · Physics 2007-05-23 John J. Cowan , Christopher Sneden

We have compiled a sample of 699 stars from the recent literature with detailed chemical abundance information (spanning -4.2 < [Fe/H] < +0.3), and we compute their space velocities and Galactic orbital parameters. We identify members of…

Astrophysics · Physics 2009-11-13 Ian U. Roederer

We present chemodynamical links between the present-day Milky Way halo field star population and Galactic globular clusters (GCs) using a dataset that combines information from the $\rm{\it Gaia}$ space mission and the Sloan Digital Sky…

Astrophysics of Galaxies · Physics 2020-05-27 Michael Hanke , Andreas Koch , Zdenek Prudil , Eva K. Grebel , Ulrich Bastian

We present the results of analysis of ``snapshot'' spectra of 253 metal-poor halo stars -3.8 < [Fe/H] < -1.5 obtained in the HERES survey. The spectra are analysed using an automated line profile analysis method based on the Spectroscopy…

Stellar halos around galaxies contain key information about their formation and assembly history. Using simulations, we can trace the origins of different stellar populations in these halos, contributing to our understanding of galaxy…

We study turbulent gas diffusion affects on $r$-process abundances in Milky Way stars, by a combination of an analytical approach and a Monte Carlo simulation. Higher $r$-process event rates and faster diffusion, lead to more efficient…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Paz Beniamini , Kenta Hotokezaka

We analyze the anisotropy profile of the Milky Way's smooth, diffuse stellar halo using SDSS/SEGUE blue horizontal branch stars and SDSS/SEGUE and LAMOST K giants. These intrinsically luminous stars allow us to probe the halo to…

Astrophysics of Galaxies · Physics 2021-10-04 Sarah A. Bird , Xiang-Xiang Xue , Chao Liu , Juntai Shen , Chris Flynn , Chengqun Yang , Gang Zhao , Hai-Jun Tian

In the $\Lambda$CDM paradigm the Galactic stellar halo is predicted to harbor the accreted debris of smaller systems. To identify these systems, the H3 Spectroscopic Survey, combined with $Gaia$, is gathering 6D phase-space and chemical…

We describe the basic features of a Monte Carlo model specifically designed to follow the inhomogenous chemical evolution of the Galactic halo, taking into account the effects of local enrichment and mixing of the halo gas, and with…

Astrophysics · Physics 2007-05-23 C. Travaglio , A. Burkert , D. Galli

Highly r-process-enhanced stars are rare and usually metal-poor ([Fe/H] < - 1.0), and mainly populate the Milky Way halo and dwarf galaxies. This study presents the discovery of a relatively bright (V = 12.72), highly r-process-enhanced…

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