Aluminium-enriched metal-poor stars buried in the inner Galaxy

José G. Fernández-Trincado, Timothy C. Beers, Dante Minniti, Baitian Tang, Sandro Villanova, Doug Geisler, Angeles Pérez-Villegas, Katherine Vieira

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Stars with higher levels of aluminium and nitrogen enrichment are often key pieces in the chemical makeup of multiple populations in almost all globular clusters (GCs). There is also compelling observational evidence that some Galactic components could be partially built from dissipated GCs. The identification of such stars among metal-poor field stars may therefore provide insight into the composite nature of the Milky Way (MW) bulge and inner stellar halo, and could also reveal other chemical peculiarities. Here, based on APOGEE spectra, we report the discovery of 29 mildly metal-poor ([Fe/H] -0.7) stars with stellar atmospheres strongly enriched in aluminium (Al-rich stars: [Al/Fe] +0.5), well above the typical Galactic levels, located within the solar radius toward the bulge region, which lies in highly eccentric orbits (e 0.6). We find many similarities for almost all of the chemical species measured in this work with the chemical patterns of GCs, and therefore we propose that they have likely been dynamically ejected into the bulge and inner halo from GCs formed in situ and/or GCs formed in different progenitors of known merger events experienced by the MW, such as the Gaia-Sausage-Enceladus and/or Sequoia.

Original languageEnglish
Article numberL4
JournalAstronomy and Astrophysics
Volume643
DOIs
Publication statusPublished - 1 Nov 2020

Keywords

  • Galaxy: bulge
  • Galaxy: kinematics and dynamics
  • Galaxy: stellar content
  • Globular clusters: general
  • Stars: abundances
  • Stars: chemically peculiar

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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