CHEMICAL TAGGING IN THE SDSS-III/APOGEE SURVEY: NEW IDENTIFICATIONS OF HALO STARS WITH GLOBULAR CLUSTER ORIGINS

CHEMICAL TAGGING IN THE SDSS-III/APOGEE SURVEY: NEW IDENTIFICATIONS OF HALO STARS WITH GLOBULAR CLUSTER ORIGINS

ABSTRACT We present new identifications of five red giant stars in the Galactic halo with chemical abundance patterns that indicate they originally formed in globular clusters. Using data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Survey available through Sloan Digital...

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Bibliographic Details
Published in:The Astrophysical journal 2016-07, Vol.825 (2), p.146-146
Main Authors: Martell, Sarah L., Shetrone, Matthew D., Lucatello, Sara, Schiavon, Ricardo P., Mészáros, Szabolcs, Prieto, Carlos Allende, Hernández, D. A. García, Beers, Timothy C., Nidever, David L
Format: Article
Language:eng
Subjects:
Apogees
Galactic halos
Galaxy: formation
Galaxy: halo
Galaxy: stellar content
Globular clusters
Halos
Red giant stars
Sky surveys (astronomy)
Stars
stars: abundances
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Summary:ABSTRACT We present new identifications of five red giant stars in the Galactic halo with chemical abundance patterns that indicate they originally formed in globular clusters. Using data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Survey available through Sloan Digital Sky Survey (SDSS) Data Release 12, we first identify likely halo giants, and then search those for the well-known chemical tags associated with globular clusters, specifically enrichment in nitrogen and aluminum. We find that 2% of the halo giants in our sample have this chemical signature, in agreement with previous results. Following the interpretation in our previous work on this topic, this would imply that at least 13% of halo stars originally formed in globular clusters. Recent developments in the theoretical understanding of globular cluster formation raise questions about that interpretation, and we concede the possibility that these migrants represent a small fraction of the halo field. There are roughly as many stars with the chemical tags of globular clusters in the halo field as there are in globular clusters, whether or not they are accompanied by a much larger chemically untaggable population of former globular cluster stars.
ISSN:0004-637X
1538-4357