The present number of Galactic open clusters that have high resolution abundance determinations, not only of�[Fe/H], but also of other key elements, is largely insufficient to enable a clear modeling of the Galactic disk chemical evolution.

To increase the number of Galactic open clusters with high quality measurements.

We obtained high resolution (R ~ 30 000), high quality (S/N ~ 50–100�per pixel), echelle spectra with the fiber spectrograph FOCES, at Calar Alto, Spain, for three red clump stars in each of five Open Clusters. We used the classical equivalent width analysis method to obtain accurate abundances of sixteen elements: Al, Ba, Ca, Co, Cr, Fe, La, Mg, Na, Nd, Ni, Sc, Si, Ti, V, and Y. We also derived the oxygen abundance using spectral synthesis of the 6300��  forbidden line.

Three of the clusters were never studied previously with high resolution spectroscopy: we found [Fe/H] = +0.03�0.02 (�0.10)�dex for Cr�110; [Fe/H] = +0.01�0.05 (�0.10)�dex for NGC�2099 (M�37), and [Fe/H] = -0.05�0.03 (�0.10)�dex for NGC�2420. This last finding is higher than typical literature estimates by 0.2–0.3�dex approximately and in closer agreement with Galactic trends. For the remaining clusters, we find that [Fe/H] = +0.05�0.02 (�0.10)�dex for M�67 and [Fe/H] = +0.04�0.07 (�0.10)�dex for NGC�7789. Accurate (to ~0.5�km�s^-1) radial velocities were measured for all targets, and we provide the first velocity estimate derived from high resolution data for Cr�110, = 41.0�3.8�km�s^-1.

With our analysis of the new clusters Cr�110, NGC�2099, and NGC�2420, we increase the sample of clusters with high-resolution-based abundances by�5%. All our program stars show abundance patterns which are typical of open clusters, very close to solar with few exceptions. This is true for all the iron-peak and s-process elements considered, and no significant α-enhancement is found. No significant (anti-)correlations for�Na, Al, Mg, and O abundances are found. If anticorrelations are present, the involved spreads must be <0.2�dex. We then compile high resolution data of 57�OC from the literature and find a gradient of [Fe/H] with Galactocentric radius of –0.06�0.02�dex�kpc^-1, in agreement with past work and with results for Cepheids and B stars in the same range. A change of slope is seen outside R_GC = 12�kpc and [ α/Fe] shows a tendency to increase with R_GC. We also confirm the absence of a significant age-metallicity relation, finding slopes of –2.6�1.1  10^-11�dex�Gyr^-1 and 1.1�5.0  10^-11�dex�Gyr^-1 for [Fe/H] and [ α/Fe] respectively.