Recently an increasing number of studies were devoted to measure the abundances of neutron-capture elements heavier than iron in stars belonging to Galactic Open Clusters ( OCs ) .
OCs span a sizeable range in metallicity ( –0.6 \leq [ Fe/H ] \leq +0.4 ) , and they show abundances of light elements similar to disk stars of the same age .
A different pattern is observed for heavy elements .
A large scatter is observed for Ba , with most OCs showing [ Ba/Fe ] and [ Ba/La ] overabundant with respect to the Sun .
The origin of this overabundance is not clearly understood .
With the goal of providing new observational insights we determined radial velocities , atmospheric parameters and chemical composition of 27 giant stars members of five OCs : Cr 110 , Cr 261 , NGC 2477 , NGC 2506 and NGC 5822 .
We used high-resolution spectra obtained with the UVES spectrograph at ESO Paranal .
We perform a detailed spectroscopic analysis of these stars to measure the abundance of up to 22 elements per star .
We study the dependence of element abundance on metallicity and age with unprecedented detail , complementing our analysis with data culled from the literature .
We confirm the trend of Ba overabundance in OCs , and show its large dispersion for clusters younger than \sim 4 Gyr .
Finally , the implications of our results for stellar nucleosynthesis are discussed .
We show in this work that the Ba enrichment compared to other neutron-capture elements in OCs can not be explained by the contributions from the slow neutron-capture process and the rapid neutron-capture process .
Instead , we argue that this anomalous signature can be explained by assuming an additional contribution by the intermediate neutron-capture process .