Spectroscopy obs. of RAVE J094921.8-161722

DOI

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.

Identifier
DOI http://doi.org/10.26093/cds/vizier.18620174
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/862/174
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/862/174
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/862/174
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/862/174
Provenance
Creator Gull M.; Frebel A.; Cain M.G.; Placco V.M.; Ji A.P.; Abate C.; Ezzeddine R.,Karakas A.I.; Hansen T.T.; Sakari C.; Holmbeck E.M.; Santucci R.M.,Casey A.R.; Beers T.C.
Publisher CDS
Publication Year 2019
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy