R-Process Alliance: 1st release in Galactic halo

DOI

This paper presents the detailed abundances and r-process classifications of 125 newly identified metal-poor stars as part of an ongoing collaboration, the R-Process Alliance. The stars were identified as metal-poor candidates from the RAdial Velocity Experiment (RAVE) and were followed up at high spectral resolution (R~31500) with the 3.5m telescope at Apache Point Observatory. The atmospheric parameters were determined spectroscopically from FeI lines, taking into account non-LTE corrections and using differential abundances with respect to a set of standards. Of the 125 new stars, 124 have [Fe/H]{<}-1.5, 105 have [Fe/H]{<}-2.0, and 4 have [Fe/H]{<}-3.0. Nine new carbon-enhanced metal-poor stars have been discovered, three of which are enhanced in r-process elements. Abundances of neutron-capture elements reveal 60 new r-I stars (with +0.3<=[Eu/Fe]<=+1.0 and [Ba/Eu]+1.0). Nineteen stars are found to exhibit a "limited-r" signature ([Sr/Ba]>+0.5, [Ba/Eu]<0). For the r-II stars, the second- and third-peak main r-process patterns are consistent with the r-process signature in other metal-poor stars and the Sun. The abundances of the light, {alpha}, and Fe-peak elements match those of typical Milky Way (MW) halo stars, except for one r-I star that has high Na and low Mg, characteristic of globular cluster stars. Parallaxes and proper motions from the second Gaia data release yield UVW space velocities for these stars that are consistent with membership in the MW halo. Intriguingly, all r-II and the majority of r-I stars have retrograde orbits, which may indicate an accretion origin.

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Identifier
DOI http://doi.org/10.26093/cds/vizier.18680110
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/868/110
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/868/110
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/868/110
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/868/110
Provenance
Creator Sakari C.M.; Placco V.M.; Farrell E.M.; Roederer I.U.; Wallerstein G.,Beers T.C.; Ezzeddine R.; Frebel A.; Hansen T.; Holmbeck E.M.; Sneden C.,Cowan J.J.; Venn K.A.; Davis C.E.; Matijevic G.; Wyse R.F.G.,Bland-Hawthorn J.; Chiappini C.; Freeman K.C.; Gibson B.K.; Grebel E.K.,Helmi A.; Kordopatis G.; Kunder A.; Navarro J.; Reid W.; Seabroke G.,Steinmetz M.; Watson F.
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; Galactic and extragalactic Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy