Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Abundances in the Galaxy: field stars
- Part II Abundances in the Galaxy: Galactic stars in clusters, bulges and the centre
- 9 Galactic open clusters with supersolar metallicities
- 10 Old and very-metal-rich open clusters in the BOCCE project
- 11 Massive-star versus nebular abundances in the Orion nebula
- 12 Abundance surveys of metal-rich bulge stars
- 13 Metal abundances in the Galactic Center
- 14 Light elements in the Galactic bulge
- 15 Metallicity and ages of selected G–K giants
- Part III Observations – abundances in extragalactic contexts
- Part IV Stellar populations and mass functions
- Part V Physical processes at high metallicity
- Part VI Formation and evolution of metal-rich stars and stellar yields
- Part VII Chemical and photometric evolution beyond Solar metallicity
14 - Light elements in the Galactic bulge
Published online by Cambridge University Press: 02 December 2009
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Abundances in the Galaxy: field stars
- Part II Abundances in the Galaxy: Galactic stars in clusters, bulges and the centre
- 9 Galactic open clusters with supersolar metallicities
- 10 Old and very-metal-rich open clusters in the BOCCE project
- 11 Massive-star versus nebular abundances in the Orion nebula
- 12 Abundance surveys of metal-rich bulge stars
- 13 Metal abundances in the Galactic Center
- 14 Light elements in the Galactic bulge
- 15 Metallicity and ages of selected G–K giants
- Part III Observations – abundances in extragalactic contexts
- Part IV Stellar populations and mass functions
- Part V Physical processes at high metallicity
- Part VI Formation and evolution of metal-rich stars and stellar yields
- Part VII Chemical and photometric evolution beyond Solar metallicity
Summary
We present abundance results for 53 bulge giant stars using highresolution spectra obtained with FLAMES/UVES at the ESO/VLT for various regions of the Bulge (−12 < b < −4). The trend of the four light elements O, Na, Mg and Al indicates a chemical enrichment of the bulge dominated by massive stars at all metallicities. For [Fe/H] > −0.5, [O/Fe], [Na/Fe], [Mg/Fe] and [Al/Fe] are enhanced relative to both the thin- and the thick-disc trend. This suggests that the bulge formed on a shorter timescale than did the Galactic discs.
Using Mg as a proxy for metallicity (instead of Fe) we further show the following (i) The [O/Mg] ratio for bulge stars follows and extends to higher metallicities the decreasing trend of [O/Mg] found in the galactic discs. (ii) The [Na/Mg] ratio trend with increasing [Mg/H] is found to increase in three distinct sequences in the thin disc, the thick disc, and the bulge. The bulge trend is well represented by the predicted metallicity- dependent yields of massive stars, whereas the galactic discs have Na/Mg ratios that are too high at low metallicities, indicating an additional source of Na from AGB stars. (iii) In contrast to the case with Na, there appears to be no systematic difference in the [Al/Mg] ratio between bulge and disc stars, and the theoretical yields for massive stars agree with the observed ratios, leaving no space for an AGB contribution to Al.
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- Information
- The Metal-Rich Universe , pp. 126 - 131Publisher: Cambridge University PressPrint publication year: 2008