Manganese Abundances In The Globular Cluster Omega Centauri




Cunha, Katia
Smith, Verne V.
Bergemann, Maria
Suntzeff, Nicholas B.
Lambert, David L.

Journal Title

Journal ISSN

Volume Title



We present manganese abundances in 10 red giant members of the globular cluster omega Centauri; eight stars are from the most metal-poor population (RGB MP and RGB MInt1) while two targets are members of the more metal-rich groups (RGB MInt2 and MInt3). This is the first time Mn abundances have been studied in this peculiar stellar system. The LTE values of [Mn/Fe] in omega Cen overlap those of Milky Way stars in the metal-poor. Cen populations ([Fe/H] similar to -1.5 to -1.8), however unlike what is observed in Milky Way halo and disk stars, [Mn/Fe] declines in the two more metal-rich RGB MInt2 and MInt3 targets. Non-LTE calculations were carried out in order to derive corrections to the LTE Mn abundances. The non-LTE results for omega Cen in comparison with the non-LTE [Mn/Fe] versus [Fe/H] trend obtained for the Milky Way confirm and strengthen the conclusion that the manganese behavior in omega Cen is distinct. These results suggest that low-metallicity supernovae (with metallicities <= -2) of either Type II or Type Ia dominated the enrichment of the more metal-rich stars in omega Cen. The dominance of low-metallicity stars in the chemical evolution of omega Cen has been noted previously in the s-process elements where enrichment from metal-poor asymptotic giant branch stars is indicated. In addition, copper, which also has metallicity-dependent yields, exhibits lower values of [Cu/Fe] in the RGB MInt2 and MInt3 omega Cen populations.



LCSH Subject Headings


Cunha, Katia, Verne V. Smith, Maria Bergemann, Nicholas B. Suntzeff, and David L. Lambert. "Manganese abundances in the globular cluster ? Centauri." The Astrophysical Journal, Vol. 717, No. 1 (Jul., 2010): 333.