Cu and Zn in thick disk and thin disk stars

1. Cu and Zn in thickdisk and thindisk stars S. Bisterzo R. Gallino M. Pignatari Dipartimento Di Fisica Generale, Universita’ di Torino, Torino, Italia

2. In the solar neighbourhood we can distinguish between two main • Galactic populations of unevolved stars: the thick disk and the thin disk. • The principal differences are (Bensby et al. 2003 and reference therein): • The orbits. Thick disk stars move with a scale height of 800-1300 pc, thin disk stars with a scale height of 100-300 pc; • The velocity dispersions. Thick disk stars show a larger velocity dispersion (σu, σv , σw ) than thin disk stars; • The rotation velocity . Thick disk stars form a more slowly rotating stellar system than Thin disk stars. • The age. In general, thick disk contains stars with ages greater than thin disk stars. • The chemical composition. From spectroscopic observations the two stars populations show different trends in the case of Copper and Zinc. We propose a possible explanation. The α-elements (O, Mg, Si, Ti) also have a different behaviour for thick and thin disk stars.

3. Cu detected in unevolved stars at different metallicities SNIa Fe contribution Secondary-like contribution

4. Zn detected in unevolved stars at different metallicities Secondary-like contribution

5. [Cu/Fe] vs [Fe/H] . Thick disk stars

6. [Cu/Fe] vs [Fe/H] . Thick disk stars + Allende Prieto et al. 2004

7. [Cu/Fe] vs [Fe/H] . Thin disk stars

8. [Cu/Fe] vs [Fe/H] . Thin disk stars + Allende Prieto et al. 2004

9. [Zn/Fe] vs [Fe/H] . Thick disk stars

10. [Zn/Fe] vs [Fe/H] . Thick disk stars + Allende Prieto et al. 2004

11. [Zn/Fe] vs [Fe/H] . Thin disk stars

12. [Zn/Fe] vs [Fe/H] . Thin disk stars + Allende Prieto et al. 2004

13. [Mg/Fe] vs [Fe/H] . Thick disk stars The α-elements show a different behaviour between thick-disk and thin-disk stars populations.

14. [Mg/Fe] vs [Fe/H] . Thin disk stars

15. Discrepances between thick-disk and thin-dik populations [Si/Fe] vs [Fe/H] . Bensby et al 2003 – Thick & Thin-disk stars Prochaska et al 2000 – Thick-disk stars Reddy et al 2003 – Thin-diskstars

16. Discrepances between thick-disk and thin-dik populations [Ti/Fe] vs [Fe/H] . Bensby et al 2003 – Thick & Thin-disk stars Prochaska et al 2000 – Thick disk stars Reddy et al 2003 – Thin-diskstars

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