Searching for r-process-enhanced stars in the LAMOST Survey I: The Method

Abstract

The abundance patterns of $r$-process-enhanced stars contain key information required to constrain the astrophysical site(s) of $r$-process nucleosynthesis, and to deepen our understanding of the chemical evolution of our Galaxy. In order to expand the sample of known $r$-process-enhanced stars, we have developed a method to search for candidates in the LAMOST medium-resolution ($R\sim 7500$) spectroscopic survey by matching the observed spectra to synthetic templates around the Eu II line at 6645.1 AA. We obtain a sample of 13 metal-poor ($-2.35<[Fe/H]<-0.91$) candidates from 12,209 unique stars with 32,774 medium-resolution spectra. These candidates will be further studied by high-resolution follow-up observations in the near future. Extensions of this effort to include larger samples of stars, in particular at lower metallicity, using the strength of the Ba II line at 6496.9 AA, are described.

arXiv comment12 pages, 6 figures

References in corpus (34)

• The chemical composition of the Sun
• The First Data Release (DR1) of the LAMOST general survey
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: I. Nucleosynthesis and Abundance Ratios
• The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample
• Identification of strontium in the merger of two neutron stars
• The extreme r-element rich, iron-poor halo giant CS31082-001: Implications for the r-process site(s) and radioactive cosmochronology
• R-process enrichment from a single event in an ancient dwarf galaxy
• Collapsars as a major source of r-process elements
• Neutron Star Mergers and Nucleosynthesis of Heavy Elements
• Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger
• The r-process nucleosynthesis in the various jet-like explosions of magnetorotational core-collapse supernovae
• The Abundances of Neutron Capture Species in the Very Metal-Poor Globular Cluster M15: An Uniform Analysis of RGB and RHB Stars
• The long-term evolution of neutron star merger remnants - I. The impact of r-process nucleosynthesis
• Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger
• Nucleosynthesis-relevant conditions in neutrino-driven supernova outflows. I. Spherically symmetric hydrodynamic simulations
• From Nuclei to the Cosmos: Tracing Heavy-Element Production with the Oldest Stars
• The r-process in proto-neutron-star wind revisited
• R-process Nucleosynthesis from Three-Dimensional Magnetorotational Core-Collapse Supernovae
• The LAMOST Stellar Parameter Pipeline at Peking University --- LSP3
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• The $R$-Process Alliance: First Release from the Southern Search for $r$-Process-Enhanced Stars in the Galactic Halo
• Detailed Chemical Abundances in the r-Process-Rich Ultra-Faint Dwarf Galaxy Reticulum 2
• The Hamburg/ESO R-process Enhanced Star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• Dynamical Relics of the Ancient Galactic Halo
• An R-process enhanced star in the dwarf galaxy Tucana III
• Chemical Abundances in the Ultra-Faint Dwarf Galaxies Grus I and Triangulum II: Neutron-Capture Elements as a Defining Feature of the Faintest Dwarfs
• The R-Process Alliance: 2MASS J09544277+5246414, the Most Actinide-Enhanced R-II Star Known
• The Hamburg/ESO R-process Enhanced Star survey (HERES) X. HE 2252-4225, one more r-process enhanced and actinide-boost halo star
• Lithium-rich Giants in LAMOST Survey. I. The Catalog
• Chemical Abundance Analysis of Tucana III, the Second $r$-process Enhanced Ultra-Faint Dwarf Galaxy
• Metal-Poor Stars Observed with the Southern African Large Telescope

Cited by in corpus (5)

• Overview of the LAMOST survey in the first decade
• Neutron star mergers as the astrophysical site of the r-process in the Milky Way and its satellite galaxies
• Discovery of an Extremely r-process-enhanced Thin-disk Star with [Eu/H] = +0.78
• Correlation between U/Th and Pb/Os abundance ratios and its application in nuclear cosmochronology
• Investigating non-LTE abundances of Neodymium (Nd) in metal-poor FGK stars