2009/07/31 by Lan Zhang, Miho Ishigaki, Wako Aoki +2 · 1 citation
Physics and Astronomy · #Abundance of the chemical elements #Astronomical spectroscopy #Astronomy and Astrophysical Research #Chemical composition #Data reduction #Galactic halo #Halo #Metallicity #Scientific Research and Discoveries #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1088/0004-637x/706/2/1095
published as Astrophys.J.706:1095-1113,2009 · 50 pages, 15 figures, Accepted for publication by ApJ
arxiv created 2009/10/09 · openalex publication_date 2009/11/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.