Spectroscopy obs. of RAVE J094921.8-161722 Virtual Observatory Resource

Authors
  1. Gull M.
  2. Frebel A.
  3. Cain M.G.
  4. Placco V.M.
  5. Ji A.P.
  6. Abate C.
  7. Ezzeddine R.,Karakas A.I.
  8. Hansen T.T.
  9. Sakari C.
  10. Holmbeck E.M.
  11. Santucci R.M.,Casey A.R.
  12. Beers T.C.
  13. Published by
    CDS
Abstract

We present a high-resolution (R~35000), high signal-to-noise ratio (S/N>200) Magellan/MIKE spectrum of the star RAVE J094921.8-161722, a bright (V=11.3) metal-poor red giant star with [Fe/H]=-2.2, identified as a carbon-enhanced metal-poor (CEMP) star from the RAVE survey. We report its detailed chemical abundance signature of light fusion elements and heavy neutron-capture elements. We find J0949-1617 to be a CEMP star with s-process enhancement that must have formed from gas enriched by a prior r-process event. Light neutron-capture elements follow a low-metallicity s-process pattern, while the heavier neutron-capture elements above Eu follow an r-process pattern. The Pb abundance is high, in line with an s-process origin. Thorium is also detected, as expected from an r-process origin, as Th is not produced in the s-process. We employ nucleosynthesis model predictions that take an initial r-process enhancement into account, and then determine the mass transfer of carbon and s-process material from a putative more massive companion onto the observed star. The resulting abundances agree well with the observed pattern. We conclude that J0949-1617 is the first bonafide CEMP-r+s star identified. This class of objects has previously been suggested to explain stars with neutron-capture element patterns that originate from neither the r- nor the s-process alone. We speculate that J0949-1617 formed in an environment similar to those of ultra-faint dwarf galaxies like TucanaIII and ReticulumII, which were enriched in r-process elements by one or multiple neutron star mergers at the earliest times.

Keywords
  1. Chemically peculiar stars
  2. Giant stars
  3. Line intensities
  4. Chemical abundances
  5. Radial velocity
  6. Optical astronomy
Bibliographic source Bibcode
2018ApJ...862..174G
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/862/174
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/862/174
Document Object Identifer DOI
doi:10.26093/cds/vizier.18620174

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History

2019-08-29T11:45:56Z
Resource record created
2019-08-29T11:45:56Z
Created
2020-02-14T06:14:23Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
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