Elevated r-process Enrichment in Gaia Sausage and Sequoia*

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dc.contributor.authorAguado, David S.
dc.contributor.authorBelokurov, Vasily
dc.contributor.authorMyeong, G. C.
dc.contributor.authorEvans, N. Wyn
dc.contributor.authorKobayashi, Chiaki
dc.contributor.authorSbordone, Luca
dc.contributor.authorChaname, Julio
dc.contributor.authorNavarrete, Camila
dc.contributor.authorKoposov, Sergey E.
dc.date.accessioned2025-01-20T23:55:00Z
dc.date.available2025-01-20T23:55:00Z
dc.date.issued2021
dc.description.abstractThe Gaia Sausage (GS) and the Sequoia represent the major accretion events that formed the stellar halo of the Milky Way. A detailed chemical study of these main building blocks provides a pristine view of the early steps of the Galaxy's assembly. We present the results of the analysis of the UVES high-resolution spectroscopic observations at the 8.2 m VLT of nine Sausage/Sequoia members selected kinematically using Gaia DR2. We season this set of measurements with archival data from Nissen & Schuster and GALAH DR3 (2020). Here, we focus on the neutron-capture process by analyzing Sr, Y, Ba, and Eu behavior. We detect clear enhancement in Eu abundance ([Eu/Fe] similar to 0.6-0.7) indicative of large prevalence of the r-process in the stellar n-capture makeup. We are also able to trace the evolution of the heavy element production across a wide range of metallicity. The barium to europium changes from a tight, flat sequence with [Ba/Eu] = -0.7 reflecting dominant contribution from exploding massive stars, to a clear upturn at higher iron abundances, betraying the onset of contamination from asymptotic giant branch (AGB) ejecta. Additionally, we discover two clear sequences in the [Fe/H]-[Ba/Fe] plane likely caused by distinct levels of s-process pollution and mixing within the GS progenitor.
dc.fuente.origenWOS
dc.identifier.doi10.3847/2041-8213/abdbb8
dc.identifier.eissn2041-8213
dc.identifier.issn2041-8205
dc.identifier.urihttps://doi.org/10.3847/2041-8213/abdbb8
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/95065
dc.identifier.wosidWOS:000616786900001
dc.issue.numero1
dc.language.isoen
dc.revistaAstrophysical journal letters
dc.rightsacceso restringido
dc.subjectPopulation II stars
dc.subjectGalaxy formation
dc.subjectHalo stars
dc.subjectMilky Way stellar halo
dc.subjectNuclear astrophysics
dc.subjectNuclear abundances
dc.subjectGalaxy chemical evolution
dc.subjectChemical abundances
dc.subjectDwarf galaxies
dc.titleElevated r-process Enrichment in Gaia Sausage and Sequoia*
dc.typeartículo
dc.volumen908
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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