Chemical compositions of kinematically selected outer halo stars

Lan Zhang, Miho Ishigaki, Wako Aoki, Gang Zhao, Masashi Chiba

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Chemical abundances of 26 metal-poor dwarfs and giants are determined from high-resolution and high signal-to-noise ratio spectra obtained with the Subaru/High Dispersion Spectrograph. The sample is selected so that most of the objects have outer-halo kinematics. Self-consistent atmospheric parameters were determined by an iterative procedure based on spectroscopic analysis. Abundances of 13 elements, including α-elements (Mg, Si, Ca, Ti), odd-Z light elements (Na, Sc), iron-peak elements (Cr, Mn, Fe, Ni, Zn), and neutron-capture elements (Y, Ba), are determined by two independent data reduction and local thermodynamic equillibrium analysis procedures, confirming the consistency of the stellar parameters and abundances results. We find a decreasing trend of [α/Fe] with increasing [Fe/H] for the range of -3.5< [Fe/H] <-1, as found by Stephens & Boesgaard. [Zn/Fe] values of most objects in our sample are slightly lower than the bulk of halo stars previously studied. These results are discussed as possible chemical properties of the outer halo in the Galaxy.

Original languageEnglish
Pages (from-to)1095-1113
Number of pages19
JournalAstrophysical Journal
Volume706
Issue number2
DOIs
Publication statusPublished - 2009 Dec 1

Keywords

  • Galaxy: Abundances
  • Galaxy: Evolution
  • Galaxy: Halo
  • Stars: Abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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