Metallicities of open and globular cluster giants determined from new DDO abundance calibrations

Abstract

New empirical DDO abundance calibrations for population I and II late-type giants are presented. Blanketing vectors and isoabundance lines in the EDO two-color diagrams are determined. The new abundance index, δ4548, correlates very well with the metallicity even for stars with [Fe/H] = -3.0. New DDO abundance determinations in open and globular cluster giants show general good agreement with the scales of Friel and Janes (1992, A&A, in press) and Zinn (1985, Ap.J. 293, 424), for open and globular clusters, respectively. This paper will be published in detail elsewhere.