Sulphur and Zinc Abundances in Halo and Disk Stars
Abstract
Sulphur and zinc are key elements in studies of the chemical evolution of DLAs because they are undepleted on interstellar dust. It is often assumed that S is an ""alpha""-element made by Type II supernovae whereas Zn follows iron in its chemical evolution. If correct the S/Zn ratio can be used as ""a chemical clock"" to date the star formation process in DLAs. Recent studies of S/Fe and Zn/Fe in Galactic stars have however questioned these assumptions.
In order to advance the study of the chemical evolution of S and Zn in our Galaxy we have obtained high resolution ESO VLT/UVES spectra for 35 halo stars and the Xinglong 2.16m telescope has been used to observe disk stars. From a model atmosphere analysis of these spectra including estimates of 3D effects we have derived the trends of S/Fe and Zn/Fe for Galactic stars in the metallicity range -3.2 < [Fe/H] < +0.2. Preliminary results suggest that S behaves like an ""alpha""-element whereas Zn may show small deviations from the trend of iron.- Publication:
-
IAU Joint Discussion
- Pub Date:
- 2003
- Bibcode:
- 2003IAUJD..15E..26N