Disentangling the Galactic Halo with APOGEE. I. Chemical and Kinematical Investigation of Distinct Metal-poor Populations

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dc.contributor.authorHayes, Christian R.
dc.contributor.authorMajewski, Steven R.
dc.contributor.authorShetrone, Matthew
dc.contributor.authorFernandez-Alvar, Emma
dc.contributor.authorAllende Prieto, Carlos
dc.contributor.authorSchuster, William J.
dc.contributor.authorCarigi, Leticia
dc.contributor.authorCunha, Katia
dc.contributor.authorSmith, Verne V.
dc.contributor.authorSobeck, Jennifer
dc.contributor.authorAlmeida, Andres
dc.contributor.authorBeers, Timothy C.
dc.contributor.authorCarrera, Ricardo
dc.contributor.authorFernandez-Trincado, J. G.
dc.contributor.authorGarcia-Hernandez, D. A.
dc.contributor.authorGeisler, Doug
dc.contributor.authorLane, Richard R.
dc.contributor.authorLucatello, Sara
dc.contributor.authorMatthews, Allison M.
dc.contributor.authorMinniti, Dante
dc.contributor.authorNitschelm, Christian
dc.contributor.authorTang, Baitian
dc.contributor.authorTissera, Patricia B.
dc.contributor.authorZamora, Olga
dc.date.accessioned2025-01-23T21:23:28Z
dc.date.available2025-01-23T21:23:28Z
dc.date.issued2018
dc.description.abstractWe find two chemically distinct populations separated relatively cleanly in the [Fe/H]-[Mg/Fe] plane, but also distinguished in other chemical planes, among metal-poor stars (primarily with metallicities [Fe/H] < -0.9) observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and analyzed for Data Release 13 (DR13) of the Sloan Digital Sky Survey. These two stellar populations show the most significant differences in their [X/Fe] ratios for the alpha-elements, C+N, Al, and Ni. In addition to these populations having differing chemistry, the low metallicity high-Mg population (which we denote "the HMg population") exhibits a significant net Galactic rotation, whereas the low-Mg population (or "the LMg population") has halo-like kinematics with little to no net rotation. Based on its properties, the origin of the LMg population is likely an accreted population of stars. The HMg population shows chemistry (and to an extent kinematics) similar to the thick disk, and is likely associated with in situ formation. The distinction between the LMg and HMg populations mimics the differences between the populations of low-and high-a halo stars found in previous studies, suggesting that these are samples of the same two populations.
dc.fuente.origenWOS
dc.identifier.doi10.3847/1538-4357/aa9cec
dc.identifier.eissn1538-4357
dc.identifier.issn0004-637X
dc.identifier.urihttps://doi.org/10.3847/1538-4357/aa9cec
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/101283
dc.identifier.wosidWOS:000419455800004
dc.issue.numero1
dc.language.isoen
dc.revistaAstrophysical journal
dc.rightsacceso restringido
dc.subjectGalaxy: disk
dc.subjectGalaxy: evolution
dc.subjectGalaxy: formation
dc.subjectGalaxy: halo
dc.subjectstars: abundances
dc.titleDisentangling the Galactic Halo with APOGEE. I. Chemical and Kinematical Investigation of Distinct Metal-poor Populations
dc.typeartículo
dc.volumen852
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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