The chemical compositions and evolutionary status of red giants in the open cluster NGC 752

We present detailed chemical compositions of 10 red giant star members of the Galactic (open) cluster NGC 752, derived from high-resolution (R approximate to 60 000), high signal-to-noise (S/N >= 140) spectra. We confirmed cluster memberships by measuring the stellar radial velocities, and by deriving model atmosphere parameters (T-eff, log g, [Fe/H] and xi(t)) from equivalent widths of Fe I, FeII, Ti I, and Ti II lines. The metallicity we obtained for NGC 752 ([Fe/H]= -0.02 +/- 0.05) is in good agreement with previous studies. We derived abundances of alpha (Mg, Si, Ca), light odd-Z (Na, A1), Fe-group (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), n-capture (Y, La, Nd, Eu), and p-capture (Li, C, N, O) species for each star. Furthermore, we also derived abundances of the LiCNO p-capture element group and carbon isotopic ratios, using synthetic spectrum analyses of the Li I 6707 angstrom resonance doublet, the [O I] line at 6300 angstrom, the CH G-band features near 4311 and 4325 angstrom, the C-2 bandheads at 5160 and 5631 angstrom, and (CN)-C-12,13 red system lines in the 7995-8040 angstrom region. By applying recent isochrones to NGC 752 photometry, and comparing the colour-magnitude diagram information to our Li abundances and C-12/C-13 ratios, we suggest that the 10 observed red giants can be separated into three first-ascent, six red-clump and one red horizontal branch star.