A differential chemical abundance scale for the globular cluster M5

Abstract

We present LTE chemical abundances for five red giants and one AGB star in the Galactic globular cluster (GC) M5 based on high resolution spectroscopy using the MIKE spectrograph on the Magellan 6.5-m Clay telescope. Our results are based on a line-by-line differential abundance analysis relative to the well-studied red giant Arcturus. The stars in our sample that overlap with existing studies in the literature are consistent with published values for [Fe/H] and agree to within typically 0.04 dex for the alpha-elements. Most deviations can be assigned to varying analysis techniques in the literature. This strengthens our newly established differential GC abundance scale and advocates future use of this method. In particular, we confirm a mean [Fe I/H] of -1.33 +- 0.03 (stat.) +- 0.03 (sys.) dex and also reproduce M5's enhancement in the alpha-elements (O,Mg,Si,Ca,Ti) at +0.4 dex, rendering M5 a typical representative of the Galactic halo. Over-ionization of Fe I in the atmospheres of these stars by non-LTE effects is found to be less than 0.07 dex. Five of our six stars show O-Na-Al-Mg abundance patterns consistent with pollution by proton-capture nucleosynthesis products.

12 pages, 7 figures, accepted for publication in the AJ

References in corpus (10)

• Na-O Anticorrelation and HB. VII. The chemical composition of first and second-generation stars in 15 globular clusters from GIRAFFE spectra
• Intrinsic iron spread and a new metallicity scale for Globular Clusters
• Na-O Anticorrelation and HB. VIII. Proton-capture elements and metallicities in 17 globular clusters from UVES spectra
• The Highly Unusual Chemical Composition of the Hercules Dwarf Spheroidal Galaxy
• Chemical Abundances and Kinematics in Globular Clusters and Local Group Dwarf Galaxies and Their Implications for Formation Theories of the Galactic Halo
• A new abundance scale for the globular cluster 47 Tuc
• Heavy element abundances in giant stars of the globular clusters M4 and M5
• Evidence of enrichment by individual supernova from elemental abundance ratios in the very metal-poor dSph galaxy Bootes I
• Rubidium and lead abundances in giant stars of the globular clusters M4 and M5
• All quiet in the outer halo: chemical abundances in the globular cluster Pal 3

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