Differential chemical abundance analysis of a 47 Tuc AGB star with respect to Arcturus

Abstract

This study resolves a discrepancy in the abundance of Zr in the 47 Tucanae asymptotic giant branch star Lee 2525. This star was observed using the echelle spectrograph on the 2.3 m telescope at Siding Spring Observatory. The analysis was undertaken by calibrating Lee 2525 with respect to the standard giant star Arcturus. This work emphasises the importance of using a standard star with stellar parameters comparable to the star under analysis rather than a calibration with respect to the Sun (Koch & McWilliam 2008). Systematic errors in the analysis process are then minimised due to the similarity in atmospheric structure between the standard and programme stars. The abundances derived for Lee 2525 were found to be in general agreement with the Brown & Wallerstein (1992) values except for Zr. In this study Zr has a similar enhancement ([Zr/Fe] = +0.51 dex) to another light s-process element, Y ([Y/Fe] = +0.53 dex), which reflects current theory regarding the enrichment of s-process elements by nuclear processes within AGB stars (Busso et al. 2001). This is contrary to the results of Brown & Wallerstein (1992) where Zr was under-abundant ([Zr/Fe] = +0.51 dex) and Y was over-abundant ([Y/Fe] = +0.50 dex) with respect to Fe.

11 pages, 5 figures Accepted for publication in MNRAS

References in corpus (6)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Abundances of Baade's Window Giants from Keck/HIRES Spectra: II. The Alpha- and Light Odd Elements
• A new abundance scale for the globular cluster 47 Tuc
• Heavy elements and chemical enrichment in globular clusters
• Heavy Element Abundances in Giant Stars of 47 Tuc
• s- and r-process element abundances in the CMD of 47 Tucanae using the Robert Stobie Spectrograph on SALT

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