Synthetic Lick indices of alpha-enhanced stars

Synthetic Lick indices computed with solar scaled abundances and with {alpha}-element enhancement are presented and compared with predictions from both theoretical computations (Tripicco & Bell (1995AJ....110.3035T); Thomas, Maraston, & Bender (2003MNRAS.339..897T); Barbuy et al., 2003, Cat. <J/A+A/404/661>) and empirical fitting functions (de Freitas Pacheco, 1996MNRAS.278..841D). We propose selected combinations of indices capable of singling out {alpha}-enhanced stars without requiring previous knowledge of their main atmospheric parameters.

By applying this approach to the 460 stars in the Worthey et al. (1994, Cat. <J/ApJS/94/687>) catalog, we detected a list of 82 candidate {alpha}-enhanced stars. The confirmation of {alpha}-enhancement was obtained by searching the literature for individual element abundance determinations from high-resolution spectroscopy for a subsample of 34 stars. Preliminary discussion of the properties of the detected {alpha}-enhanced stars with respect to their [Fe/H] values and kinematics is presented.