期刊
ASTROPHYSICAL JOURNAL LETTERS
卷 886, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.3847/2041-8213/ab5286
关键词
Chemically peculiar stars; Stellar dynamics; Galaxy stellar content; Galaxy stellar halos; Silicon stars; High resolution spectroscopy; Stellar abundances; Stellar kinematics
资金
- FONDECYT [3180210, 1170518, 1170121]
- European COST Action [CA16117, 41736]
- Physics Frontier Center/JINA Center for the Evolution of the Elements (JINA-CEE) - US National Science Foundation [PHY 14-30152]
- National Natural Science Foundation of China [U1931102]
- hundred-talent project of Sun Yat-sen University
- FAPESP [2017/15893-1]
- DGAPA-PAPIIT grant [IG100319]
- UNAM/PAPIIT grant [IN105916]
- BASAL Center for Astrophysics and Associated Technologies (CATA) [AFB 170002]
- Ministry for the Economy, Development and Tourism, Programa Iniciativa Cientifica Milenio grant [IC120009]
- Region de Franche-Comte
- Institut des Sciences de l'Univers (INSU)
- Centre national d'etudes spatiales (CNES) [0101973]
- UTINAM Institute of the Universite de Franche-Comte - Region de Franche-Comte
- UTINAM Institute of the Universite de Franche-Comte - Institut des Sciences de l'Univers (INSU)
- Alfred P. Sloan Foundation
- U.S. Department of Energy Office of Science
- Center for High-Performance Computing at the University of Utah
- Brazilian Participation Group
- Carnegie Institution for Science
- Carnegie Mellon University
- Chilean Participation Group
- French Participation Group
- Harvard-Smithsonian Center for Astrophysics
- Instituto de Astrofisica de Canarias
- Johns Hopkins University
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo
- Lawrence Berkeley National Laboratory
- Leibniz Institut fur Astrophysik Potsdam (AIP)
- Max-Planck-Institut fur Astronomie (MPIA Heidelberg)
- Max-Planck-Institut fur Astrophysik (MPA Garching)
- Max-Planck-Institut fur Extraterrestrische Physik (MPE)
- National Astronomical Observatory of China
- New Mexico State University
- New York University
- University of Dame
- Observatorio Nacional/MCTI
- Ohio State University
- Pennsylvania State University
- Shanghai Astronomical Observatory
- United Kingdom Participation Group
- Universidad Nacional Autonoma de Mexico
- University of Arizona
- University of Colorado Boulder
- University of Oxford
- University of Portsmouth
- University of Utah
- University of Virginia
- University of Washington
- University of Wisconsin
- Vanderbilt University
- Yale University
We report the discovery of a unique collection of metal-poor giant stars that exhibit anomalously high levels of Si-28, clearly above typical Galactic levels. Our sample spans a narrow range of metallicities, peaking at ?1.07;;0.06, and exhibits abundance ratios of [Si, Al/Fe] that are as extreme as those observed in Galactic globular clusters (GCs), and Mg is slightly less overabundant. In almost all the sources we used, the elemental abundances were redetermined from high-resolution spectra, which were reanalyzed assuming LTE. Thus, we compiled the main element families, namely, the light elements (C, N), ?-elements (O, Mg, Si), iron-peak element (Fe), s-process elements (Ce, Nd), and the light odd-Z element (Al). We also provide dynamical evidence that most of these stars lie on tight (inner) halo-like and retrograde orbits passing through the bulge. Such kinds of objects have been found in present-day halo GCs, providing the clearest chemical signature of past accretion events in the (inner) stellar halo of the galaxy, possibly formed as the result of dissolved halo GCs. Their chemical composition is, in general, similar to that of typical GC populations, although several differences exist.
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